Update mr1441 and mr3729

Signed-off-by: Mingi Sung <sungmg@saltyming.net>

1 files changed, 2357 insertions, 1166 deletions

diff --git a/mr1441.patch b/mr1441.patch
index e4259b6d1097..b4041a3979ff 100644
--- a/mr1441.patch
+++ b/mr1441.patch
@@ -1,7 +1,6 @@
 Author: Daniel van Vugt <daniel.van.vugt@canonical.com>
 Source: https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1441
-Commit: abe84f8ef3e075f7caae6ced8dfb6d536948d2d8
-Last Updated: 04/29/24 (Mutter 46.1)
+Source: https://gitlab.gnome.org/Community/Ubuntu/mutter/-/tree/triple-buffering-v4-46
 ---
 
 Use triple buffering if and when the previous frame is running late.
@@ -15,794 +14,30 @@ If the previous frame is not running late then we stick to double buffering so
 there's no latency penalty when the system is able to maintain full frame rate.
 
 ---
-diff --git a/clutter/clutter/clutter-frame-clock.c b/clutter/clutter/clutter-frame-clock.c
-index 93e4c9329020286d3c1202ef4f6420b2deb74942..b637fac637f956b2ae5eb71b755f4f00bf689062 100644
---- a/clutter/clutter/clutter-frame-clock.c
-+++ b/clutter/clutter/clutter-frame-clock.c
-@@ -42,6 +42,15 @@ enum
- 
- static guint signals[N_SIGNALS];
- 
-+typedef enum
-+{
-+  TRIPLE_BUFFERING_MODE_NEVER,
-+  TRIPLE_BUFFERING_MODE_AUTO,
-+  TRIPLE_BUFFERING_MODE_ALWAYS,
-+} TripleBufferingMode;
-+
-+static TripleBufferingMode triple_buffering_mode = TRIPLE_BUFFERING_MODE_AUTO;
-+
- #define SYNC_DELAY_FALLBACK_FRACTION 0.875
- 
- #define MINIMUM_REFRESH_RATE 30.f
-@@ -70,8 +79,10 @@ typedef enum _ClutterFrameClockState
-   CLUTTER_FRAME_CLOCK_STATE_IDLE,
-   CLUTTER_FRAME_CLOCK_STATE_SCHEDULED,
-   CLUTTER_FRAME_CLOCK_STATE_SCHEDULED_NOW,
--  CLUTTER_FRAME_CLOCK_STATE_DISPATCHING,
--  CLUTTER_FRAME_CLOCK_STATE_PENDING_PRESENTED,
-+  CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE,
-+  CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE_AND_SCHEDULED,
-+  CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE_AND_SCHEDULED_NOW,
-+  CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_TWO,
- } ClutterFrameClockState;
- 
- struct _ClutterFrameClock
-@@ -92,6 +103,7 @@ struct _ClutterFrameClock
-   ClutterFrameClockMode mode;
- 
-   int64_t last_dispatch_time_us;
-+  int64_t prev_last_dispatch_time_us;
-   int64_t last_dispatch_lateness_us;
-   int64_t last_presentation_time_us;
-   int64_t next_update_time_us;
-@@ -111,6 +123,9 @@ struct _ClutterFrameClock
-   int64_t vblank_duration_us;
-   /* Last KMS buffer submission time. */
-   int64_t last_flip_time_us;
-+  int64_t prev_last_flip_time_us;
-+
-+  ClutterFrameHint last_flip_hints;
- 
-   /* Last time we promoted short-term maximum to long-term one */
-   int64_t longterm_promotion_us;
-@@ -245,10 +260,6 @@ static void
- maybe_update_longterm_max_duration_us (ClutterFrameClock *frame_clock,
-                                        ClutterFrameInfo  *frame_info)
- {
--  /* Do not update long-term max if there has been no measurement */
--  if (!frame_clock->shortterm_max_update_duration_us)
--    return;
--
-   if ((frame_info->presentation_time - frame_clock->longterm_promotion_us) <
-       G_USEC_PER_SEC)
-     return;
-@@ -275,6 +286,12 @@ void
- clutter_frame_clock_notify_presented (ClutterFrameClock *frame_clock,
-                                       ClutterFrameInfo  *frame_info)
- {
-+#ifdef CLUTTER_ENABLE_DEBUG
-+  const char *debug_state =
-+    frame_clock->state == CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_TWO ?
-+    "Triple buffering" : "Double buffering";
-+#endif
-+
-   COGL_TRACE_BEGIN_SCOPED (ClutterFrameClockNotifyPresented,
-                            "Clutter::FrameClock::presented()");
-   COGL_TRACE_DESCRIBE (ClutterFrameClockNotifyPresented,
-@@ -361,22 +378,52 @@ clutter_frame_clock_notify_presented (ClutterFrameClock *frame_clock,
- 
-   frame_clock->got_measurements_last_frame = FALSE;
- 
--  if (frame_info->cpu_time_before_buffer_swap_us != 0 &&
--      frame_info->has_valid_gpu_rendering_duration)
-+  if ((frame_info->cpu_time_before_buffer_swap_us != 0 &&
-+       frame_info->has_valid_gpu_rendering_duration) ||
-+      frame_clock->ever_got_measurements)
-     {
-       int64_t dispatch_to_swap_us, swap_to_rendering_done_us, swap_to_flip_us;
-+      int64_t dispatch_time_us = 0, flip_time_us = 0;
- 
--      dispatch_to_swap_us =
--        frame_info->cpu_time_before_buffer_swap_us -
--        frame_clock->last_dispatch_time_us;
-+      switch (frame_clock->state)
-+        {
-+        case CLUTTER_FRAME_CLOCK_STATE_INIT:
-+        case CLUTTER_FRAME_CLOCK_STATE_IDLE:
-+        case CLUTTER_FRAME_CLOCK_STATE_SCHEDULED:
-+        case CLUTTER_FRAME_CLOCK_STATE_SCHEDULED_NOW:
-+          g_warn_if_reached ();
-+          G_GNUC_FALLTHROUGH;
-+        case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE:
-+        case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE_AND_SCHEDULED:
-+        case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE_AND_SCHEDULED_NOW:
-+          dispatch_time_us = frame_clock->last_dispatch_time_us;
-+          flip_time_us = frame_clock->last_flip_time_us;
-+          break;
-+        case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_TWO:
-+          dispatch_time_us = frame_clock->prev_last_dispatch_time_us;
-+          flip_time_us = frame_clock->prev_last_flip_time_us;
-+          break;
-+        }
-+
-+      if (frame_info->cpu_time_before_buffer_swap_us == 0)
-+        {
-+          /* Cursor-only updates with no "swap" or "flip" */
-+          dispatch_to_swap_us = 0;
-+          swap_to_flip_us = 0;
-+        }
-+      else
-+        {
-+          dispatch_to_swap_us = frame_info->cpu_time_before_buffer_swap_us -
-+                                dispatch_time_us;
-+          swap_to_flip_us = flip_time_us -
-+                            frame_info->cpu_time_before_buffer_swap_us;
-+        }
-       swap_to_rendering_done_us =
-         frame_info->gpu_rendering_duration_ns / 1000;
--      swap_to_flip_us =
--        frame_clock->last_flip_time_us -
--        frame_info->cpu_time_before_buffer_swap_us;
- 
-       CLUTTER_NOTE (FRAME_TIMINGS,
--                    "update2dispatch %ld µs, dispatch2swap %ld µs, swap2render %ld µs, swap2flip %ld µs",
-+                    "%s: update2dispatch %ld µs, dispatch2swap %ld µs, swap2render %ld µs, swap2flip %ld µs",
-+                    debug_state,
-                     frame_clock->last_dispatch_lateness_us,
-                     dispatch_to_swap_us,
-                     swap_to_rendering_done_us,
-@@ -386,7 +433,7 @@ clutter_frame_clock_notify_presented (ClutterFrameClock *frame_clock,
-         CLAMP (frame_clock->last_dispatch_lateness_us + dispatch_to_swap_us +
-                MAX (swap_to_rendering_done_us, swap_to_flip_us),
-                frame_clock->shortterm_max_update_duration_us,
--               frame_clock->refresh_interval_us);
-+               2 * frame_clock->refresh_interval_us);
- 
-       maybe_update_longterm_max_duration_us (frame_clock, frame_info);
- 
-@@ -395,7 +442,8 @@ clutter_frame_clock_notify_presented (ClutterFrameClock *frame_clock,
-     }
-   else
-     {
--      CLUTTER_NOTE (FRAME_TIMINGS, "update2dispatch %ld µs",
-+      CLUTTER_NOTE (FRAME_TIMINGS, "%s: update2dispatch %ld µs",
-+                    debug_state,
-                     frame_clock->last_dispatch_lateness_us);
-     }
- 
-@@ -413,11 +461,22 @@ clutter_frame_clock_notify_presented (ClutterFrameClock *frame_clock,
-     case CLUTTER_FRAME_CLOCK_STATE_SCHEDULED_NOW:
-       g_warn_if_reached ();
-       break;
--    case CLUTTER_FRAME_CLOCK_STATE_DISPATCHING:
--    case CLUTTER_FRAME_CLOCK_STATE_PENDING_PRESENTED:
-+    case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE:
-       frame_clock->state = CLUTTER_FRAME_CLOCK_STATE_IDLE;
-       maybe_reschedule_update (frame_clock);
-       break;
-+    case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE_AND_SCHEDULED:
-+      frame_clock->state = CLUTTER_FRAME_CLOCK_STATE_SCHEDULED;
-+      maybe_reschedule_update (frame_clock);
-+      break;
-+    case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE_AND_SCHEDULED_NOW:
-+      frame_clock->state = CLUTTER_FRAME_CLOCK_STATE_SCHEDULED_NOW;
-+      maybe_reschedule_update (frame_clock);
-+      break;
-+    case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_TWO:
-+      frame_clock->state = CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE;
-+      maybe_reschedule_update (frame_clock);
-+      break;
-     }
- }
- 
-@@ -435,26 +494,37 @@ clutter_frame_clock_notify_ready (ClutterFrameClock *frame_clock)
-     case CLUTTER_FRAME_CLOCK_STATE_SCHEDULED_NOW:
-       g_warn_if_reached ();
-       break;
--    case CLUTTER_FRAME_CLOCK_STATE_DISPATCHING:
--    case CLUTTER_FRAME_CLOCK_STATE_PENDING_PRESENTED:
-+    case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE:
-       frame_clock->state = CLUTTER_FRAME_CLOCK_STATE_IDLE;
-       maybe_reschedule_update (frame_clock);
-       break;
-+    case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE_AND_SCHEDULED:
-+      frame_clock->state = CLUTTER_FRAME_CLOCK_STATE_SCHEDULED;
-+      maybe_reschedule_update (frame_clock);
-+      break;
-+    case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE_AND_SCHEDULED_NOW:
-+      frame_clock->state = CLUTTER_FRAME_CLOCK_STATE_SCHEDULED_NOW;
-+      maybe_reschedule_update (frame_clock);
-+      break;
-+    case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_TWO:
-+      frame_clock->state = CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE;
-+      maybe_reschedule_update (frame_clock);
-+      break;
-     }
- }
- 
--static int64_t
--clutter_frame_clock_compute_max_render_time_us (ClutterFrameClock *frame_clock)
-+static gboolean
-+clutter_frame_clock_compute_max_render_time_us (ClutterFrameClock *frame_clock,
-+                                                int64_t           *max_render_time_us)
- {
-   int64_t refresh_interval_us;
--  int64_t max_render_time_us;
- 
-   refresh_interval_us = frame_clock->refresh_interval_us;
- 
-   if (!frame_clock->ever_got_measurements ||
-       G_UNLIKELY (clutter_paint_debug_flags &
-                   CLUTTER_DEBUG_DISABLE_DYNAMIC_MAX_RENDER_TIME))
--    return refresh_interval_us * SYNC_DELAY_FALLBACK_FRACTION;
-+    return FALSE;
- 
-   /* Max render time shows how early the frame clock needs to be dispatched
-    * to make it to the predicted next presentation time. It is an estimate of
-@@ -468,15 +538,15 @@ clutter_frame_clock_compute_max_render_time_us (ClutterFrameClock *frame_clock)
-    * - The duration of vertical blank.
-    * - A constant to account for variations in the above estimates.
-    */
--  max_render_time_us =
-+  *max_render_time_us =
-     MAX (frame_clock->longterm_max_update_duration_us,
-          frame_clock->shortterm_max_update_duration_us) +
-     frame_clock->vblank_duration_us +
-     clutter_max_render_time_constant_us;
- 
--  max_render_time_us = CLAMP (max_render_time_us, 0, refresh_interval_us);
-+  *max_render_time_us = CLAMP (*max_render_time_us, 0, 2 * refresh_interval_us);
- 
--  return max_render_time_us;
-+  return TRUE;
- }
- 
- static void
-@@ -491,7 +561,9 @@ calculate_next_update_time_us (ClutterFrameClock *frame_clock,
-   int64_t min_render_time_allowed_us;
-   int64_t max_render_time_allowed_us;
-   int64_t next_presentation_time_us;
-+  int64_t next_smooth_presentation_time_us = 0;
-   int64_t next_update_time_us;
-+  gboolean max_render_time_is_known;
- 
-   now_us = g_get_monotonic_time ();
- 
-@@ -511,10 +583,13 @@ calculate_next_update_time_us (ClutterFrameClock *frame_clock,
-     }
- 
-   min_render_time_allowed_us = refresh_interval_us / 2;
--  max_render_time_allowed_us =
--    clutter_frame_clock_compute_max_render_time_us (frame_clock);
- 
--  if (min_render_time_allowed_us > max_render_time_allowed_us)
-+  max_render_time_is_known =
-+    clutter_frame_clock_compute_max_render_time_us (frame_clock,
-+                                                    &max_render_time_allowed_us);
-+
-+  if (max_render_time_is_known &&
-+      min_render_time_allowed_us > max_render_time_allowed_us)
-     min_render_time_allowed_us = max_render_time_allowed_us;
- 
-   /*
-@@ -535,7 +610,28 @@ calculate_next_update_time_us (ClutterFrameClock *frame_clock,
-    *
-    */
-   last_presentation_time_us = frame_clock->last_presentation_time_us;
--  next_presentation_time_us = last_presentation_time_us + refresh_interval_us;
-+  switch (frame_clock->state)
-+    {
-+    case CLUTTER_FRAME_CLOCK_STATE_INIT:
-+    case CLUTTER_FRAME_CLOCK_STATE_IDLE:
-+    case CLUTTER_FRAME_CLOCK_STATE_SCHEDULED:
-+    case CLUTTER_FRAME_CLOCK_STATE_SCHEDULED_NOW:
-+      next_smooth_presentation_time_us = last_presentation_time_us +
-+                                         refresh_interval_us;
-+      break;
-+    case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE:
-+    case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE_AND_SCHEDULED:
-+    case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE_AND_SCHEDULED_NOW:
-+      next_smooth_presentation_time_us = last_presentation_time_us +
-+                                         2 * refresh_interval_us;
-+      break;
-+    case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_TWO:
-+      next_smooth_presentation_time_us = last_presentation_time_us +
-+                                         3 * refresh_interval_us;
-+      break;
-+    }
-+
-+  next_presentation_time_us = next_smooth_presentation_time_us;
- 
-   /*
-    * However, the last presentation could have happened more than a frame ago.
-@@ -601,7 +697,7 @@ calculate_next_update_time_us (ClutterFrameClock *frame_clock,
-         }
-     }
- 
--  if (next_presentation_time_us != last_presentation_time_us + refresh_interval_us)
-+  if (next_presentation_time_us != next_smooth_presentation_time_us)
-     {
-       /* There was an idle period since the last presentation, so there seems
-        * be no constantly updating actor. In this case it's best to start
-@@ -613,6 +709,24 @@ calculate_next_update_time_us (ClutterFrameClock *frame_clock,
-     }
-   else
-     {
-+      /* If the max render time isn't known then using the current value of
-+       * next_presentation_time_us is suboptimal. Targeting always one frame
-+       * prior to that we'd lose the ability to scale up to triple buffering
-+       * on late presentation. But targeting two frames prior we would be
-+       * always triple buffering even when not required.
-+       *   So the algorithm for deciding when to scale up to triple buffering
-+       * in the absence of render time measurements is to simply target full
-+       * frame rate. If we're keeping up then we'll stay double buffering. If
-+       * we're not keeping up then this will switch us to triple buffering.
-+       */
-+      if (!max_render_time_is_known)
-+        {
-+          max_render_time_allowed_us =
-+            refresh_interval_us * SYNC_DELAY_FALLBACK_FRACTION;
-+          next_presentation_time_us =
-+            last_presentation_time_us + refresh_interval_us;
-+        }
-+
-       while (next_presentation_time_us - min_render_time_allowed_us < now_us)
-         next_presentation_time_us += refresh_interval_us;
- 
-@@ -644,7 +758,9 @@ calculate_next_variable_update_time_us (ClutterFrameClock *frame_clock,
- 
-   refresh_interval_us = frame_clock->refresh_interval_us;
- 
--  if (frame_clock->last_presentation_time_us == 0)
-+  if (frame_clock->last_presentation_time_us == 0 ||
-+      !clutter_frame_clock_compute_max_render_time_us (frame_clock,
-+                                                       &max_render_time_allowed_us))
-     {
-       *out_next_update_time_us =
-         frame_clock->last_dispatch_time_us ?
-@@ -657,9 +773,6 @@ calculate_next_variable_update_time_us (ClutterFrameClock *frame_clock,
-       return;
-     }
- 
--  max_render_time_allowed_us =
--    clutter_frame_clock_compute_max_render_time_us (frame_clock);
--
-   last_presentation_time_us = frame_clock->last_presentation_time_us;
-   next_presentation_time_us = last_presentation_time_us + refresh_interval_us;
- 
-@@ -733,8 +846,17 @@ clutter_frame_clock_inhibit (ClutterFrameClock *frame_clock)
-           frame_clock->pending_reschedule_now = TRUE;
-           frame_clock->state = CLUTTER_FRAME_CLOCK_STATE_IDLE;
-           break;
--        case CLUTTER_FRAME_CLOCK_STATE_DISPATCHING:
--        case CLUTTER_FRAME_CLOCK_STATE_PENDING_PRESENTED:
-+        case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE_AND_SCHEDULED:
-+          frame_clock->pending_reschedule = TRUE;
-+          frame_clock->state = CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE;
-+          break;
-+        case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE_AND_SCHEDULED_NOW:
-+          frame_clock->pending_reschedule = TRUE;
-+          frame_clock->pending_reschedule_now = TRUE;
-+          frame_clock->state = CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE;
-+          break;
-+        case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE:
-+        case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_TWO:
-           break;
-         }
- 
-@@ -753,6 +875,25 @@ clutter_frame_clock_uninhibit (ClutterFrameClock *frame_clock)
-     maybe_reschedule_update (frame_clock);
- }
- 
-+static gboolean
-+want_triple_buffering (ClutterFrameClock *frame_clock)
-+{
-+  switch (triple_buffering_mode)
-+    {
-+    case TRIPLE_BUFFERING_MODE_NEVER:
-+      return FALSE;
-+    case TRIPLE_BUFFERING_MODE_AUTO:
-+      return frame_clock->mode == CLUTTER_FRAME_CLOCK_MODE_FIXED &&
-+             !(frame_clock->last_flip_hints &
-+               CLUTTER_FRAME_HINT_DIRECT_SCANOUT_ATTEMPTED);
-+    case TRIPLE_BUFFERING_MODE_ALWAYS:
-+      return TRUE;
-+    }
-+
-+  g_assert_not_reached ();
-+  return FALSE;
-+}
-+
- void
- clutter_frame_clock_schedule_update_now (ClutterFrameClock *frame_clock)
- {
-@@ -770,11 +911,24 @@ clutter_frame_clock_schedule_update_now (ClutterFrameClock *frame_clock)
-     case CLUTTER_FRAME_CLOCK_STATE_INIT:
-     case CLUTTER_FRAME_CLOCK_STATE_IDLE:
-     case CLUTTER_FRAME_CLOCK_STATE_SCHEDULED:
-+      frame_clock->state = CLUTTER_FRAME_CLOCK_STATE_SCHEDULED_NOW;
-       break;
-     case CLUTTER_FRAME_CLOCK_STATE_SCHEDULED_NOW:
-+    case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE_AND_SCHEDULED_NOW:
-       return;
--    case CLUTTER_FRAME_CLOCK_STATE_DISPATCHING:
--    case CLUTTER_FRAME_CLOCK_STATE_PENDING_PRESENTED:
-+    case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE_AND_SCHEDULED:
-+      frame_clock->state =
-+        CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE_AND_SCHEDULED_NOW;
-+      break;
-+    case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE:
-+      if (want_triple_buffering (frame_clock))
-+        {
-+          frame_clock->state =
-+            CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE_AND_SCHEDULED_NOW;
-+          break;
-+        }
-+      G_GNUC_FALLTHROUGH;
-+    case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_TWO:
-       frame_clock->pending_reschedule = TRUE;
-       frame_clock->pending_reschedule_now = TRUE;
-       return;
-@@ -803,13 +957,17 @@ clutter_frame_clock_schedule_update_now (ClutterFrameClock *frame_clock)
- 
-   frame_clock->next_update_time_us = next_update_time_us;
-   g_source_set_ready_time (frame_clock->source, next_update_time_us);
--  frame_clock->state = CLUTTER_FRAME_CLOCK_STATE_SCHEDULED_NOW;
- }
- 
- void
- clutter_frame_clock_schedule_update (ClutterFrameClock *frame_clock)
- {
-   int64_t next_update_time_us = -1;
-+  TripleBufferingMode current_mode = triple_buffering_mode;
-+
-+  if (current_mode == TRIPLE_BUFFERING_MODE_AUTO &&
-+      !want_triple_buffering (frame_clock))
-+    current_mode = TRIPLE_BUFFERING_MODE_NEVER;
- 
-   if (frame_clock->inhibit_count > 0)
-     {
-@@ -825,12 +983,33 @@ clutter_frame_clock_schedule_update (ClutterFrameClock *frame_clock)
-       frame_clock->state = CLUTTER_FRAME_CLOCK_STATE_SCHEDULED;
-       return;
-     case CLUTTER_FRAME_CLOCK_STATE_IDLE:
-+      frame_clock->state = CLUTTER_FRAME_CLOCK_STATE_SCHEDULED;
-       break;
-     case CLUTTER_FRAME_CLOCK_STATE_SCHEDULED:
-     case CLUTTER_FRAME_CLOCK_STATE_SCHEDULED_NOW:
-+    case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE_AND_SCHEDULED:
-+    case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE_AND_SCHEDULED_NOW:
-       return;
--    case CLUTTER_FRAME_CLOCK_STATE_DISPATCHING:
--    case CLUTTER_FRAME_CLOCK_STATE_PENDING_PRESENTED:
-+    case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE:
-+      switch (current_mode)
-+        {
-+        case TRIPLE_BUFFERING_MODE_NEVER:
-+          frame_clock->pending_reschedule = TRUE;
-+          return;
-+        case TRIPLE_BUFFERING_MODE_AUTO:
-+          frame_clock->state =
-+            CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE_AND_SCHEDULED;
-+          break;
-+        case TRIPLE_BUFFERING_MODE_ALWAYS:
-+          next_update_time_us = g_get_monotonic_time ();
-+          frame_clock->next_presentation_time_us = 0;
-+          frame_clock->is_next_presentation_time_valid = FALSE;
-+          frame_clock->state =
-+            CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE_AND_SCHEDULED;
-+          return;
-+        }
-+      break;
-+    case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_TWO:
-       frame_clock->pending_reschedule = TRUE;
-       return;
-     }
-@@ -859,7 +1038,6 @@ clutter_frame_clock_schedule_update (ClutterFrameClock *frame_clock)
- 
-   frame_clock->next_update_time_us = next_update_time_us;
-   g_source_set_ready_time (frame_clock->source, next_update_time_us);
--  frame_clock->state = CLUTTER_FRAME_CLOCK_STATE_SCHEDULED;
- }
- 
- void
-@@ -875,6 +1053,8 @@ clutter_frame_clock_set_mode (ClutterFrameClock     *frame_clock,
-     {
-     case CLUTTER_FRAME_CLOCK_STATE_INIT:
-     case CLUTTER_FRAME_CLOCK_STATE_IDLE:
-+    case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE:
-+    case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_TWO:
-       break;
-     case CLUTTER_FRAME_CLOCK_STATE_SCHEDULED:
-       frame_clock->pending_reschedule = TRUE;
-@@ -885,8 +1065,14 @@ clutter_frame_clock_set_mode (ClutterFrameClock     *frame_clock,
-       frame_clock->pending_reschedule_now = TRUE;
-       frame_clock->state = CLUTTER_FRAME_CLOCK_STATE_IDLE;
-       break;
--    case CLUTTER_FRAME_CLOCK_STATE_DISPATCHING:
--    case CLUTTER_FRAME_CLOCK_STATE_PENDING_PRESENTED:
-+    case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE_AND_SCHEDULED:
-+      frame_clock->pending_reschedule = TRUE;
-+      frame_clock->state = CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE;
-+      break;
-+    case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE_AND_SCHEDULED_NOW:
-+      frame_clock->pending_reschedule = TRUE;
-+      frame_clock->pending_reschedule_now = TRUE;
-+      frame_clock->state = CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE;
-       break;
-     }
- 
-@@ -922,7 +1108,7 @@ clutter_frame_clock_dispatch (ClutterFrameClock *frame_clock,
-                              frame_clock->refresh_interval_us;
- 
-   lateness_us = time_us - ideal_dispatch_time_us;
--  if (lateness_us < 0 || lateness_us >= frame_clock->refresh_interval_us)
-+  if (lateness_us < 0 || lateness_us >= frame_clock->refresh_interval_us / 4)
-     frame_clock->last_dispatch_lateness_us = 0;
-   else
-     frame_clock->last_dispatch_lateness_us = lateness_us;
-@@ -943,10 +1129,27 @@ clutter_frame_clock_dispatch (ClutterFrameClock *frame_clock,
-     }
- #endif
- 
-+  frame_clock->prev_last_dispatch_time_us = frame_clock->last_dispatch_time_us;
-   frame_clock->last_dispatch_time_us = time_us;
-   g_source_set_ready_time (frame_clock->source, -1);
- 
--  frame_clock->state = CLUTTER_FRAME_CLOCK_STATE_DISPATCHING;
-+  switch (frame_clock->state)
-+    {
-+    case CLUTTER_FRAME_CLOCK_STATE_INIT:
-+    case CLUTTER_FRAME_CLOCK_STATE_IDLE:
-+    case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE:
-+    case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_TWO:
-+      g_warn_if_reached ();
-+      return;
-+    case CLUTTER_FRAME_CLOCK_STATE_SCHEDULED:
-+    case CLUTTER_FRAME_CLOCK_STATE_SCHEDULED_NOW:
-+      frame_clock->state = CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE;
-+      break;
-+    case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE_AND_SCHEDULED:
-+    case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE_AND_SCHEDULED_NOW:
-+      frame_clock->state = CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_TWO;
-+      break;
-+    }
- 
-   frame_count = frame_clock->frame_count++;
- 
-@@ -977,26 +1180,36 @@ clutter_frame_clock_dispatch (ClutterFrameClock *frame_clock,
-   result = iface->frame (frame_clock, frame, frame_clock->listener.user_data);
-   COGL_TRACE_END (ClutterFrameClockFrame);
- 
--  switch (frame_clock->state)
-+  switch (result)
-     {
--    case CLUTTER_FRAME_CLOCK_STATE_INIT:
--    case CLUTTER_FRAME_CLOCK_STATE_PENDING_PRESENTED:
--      g_warn_if_reached ();
-+    case CLUTTER_FRAME_RESULT_PENDING_PRESENTED:
-       break;
--    case CLUTTER_FRAME_CLOCK_STATE_IDLE:
--    case CLUTTER_FRAME_CLOCK_STATE_SCHEDULED:
--    case CLUTTER_FRAME_CLOCK_STATE_SCHEDULED_NOW:
--      break;
--    case CLUTTER_FRAME_CLOCK_STATE_DISPATCHING:
--      switch (result)
-+    case CLUTTER_FRAME_RESULT_IDLE:
-+      /* The frame was aborted; nothing to paint/present */
-+      switch (frame_clock->state)
-         {
--        case CLUTTER_FRAME_RESULT_PENDING_PRESENTED:
--          frame_clock->state = CLUTTER_FRAME_CLOCK_STATE_PENDING_PRESENTED;
-+        case CLUTTER_FRAME_CLOCK_STATE_INIT:
-+        case CLUTTER_FRAME_CLOCK_STATE_IDLE:
-+        case CLUTTER_FRAME_CLOCK_STATE_SCHEDULED:
-+        case CLUTTER_FRAME_CLOCK_STATE_SCHEDULED_NOW:
-+          g_warn_if_reached ();
-           break;
--        case CLUTTER_FRAME_RESULT_IDLE:
-+        case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE:
-           frame_clock->state = CLUTTER_FRAME_CLOCK_STATE_IDLE;
-           maybe_reschedule_update (frame_clock);
-           break;
-+        case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE_AND_SCHEDULED:
-+          frame_clock->state = CLUTTER_FRAME_CLOCK_STATE_SCHEDULED;
-+          maybe_reschedule_update (frame_clock);
-+          break;
-+        case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE_AND_SCHEDULED_NOW:
-+          frame_clock->state = CLUTTER_FRAME_CLOCK_STATE_SCHEDULED_NOW;
-+          maybe_reschedule_update (frame_clock);
-+          break;
-+        case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_TWO:
-+          frame_clock->state = CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE;
-+          maybe_reschedule_update (frame_clock);
-+          break;
-         }
-       break;
-     }
-@@ -1029,21 +1242,31 @@ frame_clock_source_dispatch (GSource     *source,
- }
- 
- void
--clutter_frame_clock_record_flip_time (ClutterFrameClock *frame_clock,
--                                      int64_t            flip_time_us)
-+clutter_frame_clock_record_flip (ClutterFrameClock *frame_clock,
-+                                 int64_t            flip_time_us,
-+                                 ClutterFrameHint   hints)
- {
-+  frame_clock->prev_last_flip_time_us = frame_clock->last_flip_time_us;
-   frame_clock->last_flip_time_us = flip_time_us;
-+  frame_clock->last_flip_hints = hints;
- }
- 
- GString *
- clutter_frame_clock_get_max_render_time_debug_info (ClutterFrameClock *frame_clock)
- {
-+  int64_t max_render_time_us;
-   int64_t max_update_duration_us;
-   GString *string;
- 
--  string = g_string_new (NULL);
--  g_string_append_printf (string, "Max render time: %ld µs",
--                          clutter_frame_clock_compute_max_render_time_us (frame_clock));
-+  string = g_string_new ("Max render time: ");
-+  if (!clutter_frame_clock_compute_max_render_time_us (frame_clock,
-+                                                       &max_render_time_us))
-+    {
-+      g_string_append (string, "unknown");
-+      return string;
-+    }
-+
-+  g_string_append_printf (string, "%ld µs", max_render_time_us);
- 
-   if (frame_clock->got_measurements_last_frame)
-     g_string_append_printf (string, " =");
-@@ -1210,8 +1433,6 @@ clutter_frame_clock_dispose (GObject *object)
- {
-   ClutterFrameClock *frame_clock = CLUTTER_FRAME_CLOCK (object);
- 
--  g_warn_if_fail (frame_clock->state != CLUTTER_FRAME_CLOCK_STATE_DISPATCHING);
--
-   if (frame_clock->source)
-     {
-       g_signal_emit (frame_clock, signals[DESTROY], 0);
-@@ -1235,6 +1456,15 @@ static void
- clutter_frame_clock_class_init (ClutterFrameClockClass *klass)
- {
-   GObjectClass *object_class = G_OBJECT_CLASS (klass);
-+  const char *mode_str;
-+
-+  mode_str = g_getenv ("MUTTER_DEBUG_TRIPLE_BUFFERING");
-+  if (!g_strcmp0 (mode_str, "never"))
-+    triple_buffering_mode = TRIPLE_BUFFERING_MODE_NEVER;
-+  else if (!g_strcmp0 (mode_str, "auto"))
-+    triple_buffering_mode = TRIPLE_BUFFERING_MODE_AUTO;
-+  else if (!g_strcmp0 (mode_str, "always"))
-+    triple_buffering_mode = TRIPLE_BUFFERING_MODE_ALWAYS;
- 
-   object_class->dispose = clutter_frame_clock_dispose;
- 
-diff --git a/clutter/clutter/clutter-frame-clock.h b/clutter/clutter/clutter-frame-clock.h
-index a7be5ef31678ffd521884d6bd784af5c74789aab..bfc89bde091660817ff5d1f02e5395668b4c3adb 100644
---- a/clutter/clutter/clutter-frame-clock.h
-+++ b/clutter/clutter/clutter-frame-clock.h
-@@ -33,6 +33,12 @@ typedef enum _ClutterFrameResult
-   CLUTTER_FRAME_RESULT_IDLE,
- } ClutterFrameResult;
- 
-+typedef enum _ClutterFrameHint
-+{
-+  CLUTTER_FRAME_HINT_NONE                     = 0,
-+  CLUTTER_FRAME_HINT_DIRECT_SCANOUT_ATTEMPTED = 1 << 0,
-+} ClutterFrameHint;
-+
- #define CLUTTER_TYPE_FRAME_CLOCK (clutter_frame_clock_get_type ())
- CLUTTER_EXPORT
- G_DECLARE_FINAL_TYPE (ClutterFrameClock, clutter_frame_clock,
-@@ -102,7 +108,8 @@ void clutter_frame_clock_remove_timeline (ClutterFrameClock *frame_clock,
- CLUTTER_EXPORT
- float clutter_frame_clock_get_refresh_rate (ClutterFrameClock *frame_clock);
- 
--void clutter_frame_clock_record_flip_time (ClutterFrameClock *frame_clock,
--                                           int64_t            flip_time_us);
-+void clutter_frame_clock_record_flip (ClutterFrameClock *frame_clock,
-+                                      int64_t            flip_time_us,
-+                                      ClutterFrameHint   hints);
- 
- GString * clutter_frame_clock_get_max_render_time_debug_info (ClutterFrameClock *frame_clock);
-diff --git a/clutter/clutter/clutter-frame-private.h b/clutter/clutter/clutter-frame-private.h
-index ef66b874edfcce434605e4dc733baac9c83ba4d3..ce140560a892c4a55632a48a6f682e8c6a370688 100644
---- a/clutter/clutter/clutter-frame-private.h
-+++ b/clutter/clutter/clutter-frame-private.h
-@@ -36,6 +36,7 @@ struct _ClutterFrame
- 
-   gboolean has_result;
-   ClutterFrameResult result;
-+  ClutterFrameHint hints;
- };
- 
- CLUTTER_EXPORT
-diff --git a/clutter/clutter/clutter-frame.c b/clutter/clutter/clutter-frame.c
-index 7436f9f182d1de116bc5c8408adec5c164292dc7..53c289b2c5a58105b77861c5362e8e035f6bebbb 100644
---- a/clutter/clutter/clutter-frame.c
-+++ b/clutter/clutter/clutter-frame.c
-@@ -115,3 +115,16 @@ clutter_frame_set_result (ClutterFrame       *frame,
-   frame->result = result;
-   frame->has_result = TRUE;
- }
-+
-+void
-+clutter_frame_set_hint (ClutterFrame     *frame,
-+                        ClutterFrameHint  hint)
-+{
-+  frame->hints |= hint;
-+}
-+
-+ClutterFrameHint
-+clutter_frame_get_hints (ClutterFrame *frame)
-+{
-+  return frame->hints;
-+}
-diff --git a/clutter/clutter/clutter-frame.h b/clutter/clutter/clutter-frame.h
-index 34f0770bd7dd630a3d9da5728254b0b5fbcc9e99..c7b3d02acb940bf5712179b576fb5eb7fae13442 100644
---- a/clutter/clutter/clutter-frame.h
-+++ b/clutter/clutter/clutter-frame.h
-@@ -54,4 +54,11 @@ void clutter_frame_set_result (ClutterFrame       *frame,
- CLUTTER_EXPORT
- gboolean clutter_frame_has_result (ClutterFrame *frame);
- 
-+CLUTTER_EXPORT
-+void clutter_frame_set_hint (ClutterFrame     *frame,
-+                             ClutterFrameHint  hint);
-+
-+CLUTTER_EXPORT
-+ClutterFrameHint clutter_frame_get_hints (ClutterFrame *frame);
-+
- G_DEFINE_AUTOPTR_CLEANUP_FUNC (ClutterFrame, clutter_frame_unref)
-diff --git a/clutter/clutter/clutter-stage-view.c b/clutter/clutter/clutter-stage-view.c
-index f5188e2acf36125c8c6c58f917a6167423d3c2eb..d53e37785101dda48e673a181a4ffc8802e09784 100644
---- a/clutter/clutter/clutter-stage-view.c
-+++ b/clutter/clutter/clutter-stage-view.c
-@@ -898,14 +898,21 @@ handle_frame_clock_frame (ClutterFrameClock *frame_clock,
- 
-       _clutter_stage_window_redraw_view (stage_window, view, frame);
- 
--      clutter_frame_clock_record_flip_time (frame_clock,
--                                            g_get_monotonic_time ());
-+      clutter_frame_clock_record_flip (frame_clock,
-+                                       g_get_monotonic_time (),
-+                                       clutter_frame_get_hints (frame));
- 
-       clutter_stage_emit_after_paint (stage, view, frame);
- 
-       if (_clutter_context_get_show_fps ())
-         end_frame_timing_measurement (view);
-     }
-+  else
-+    {
-+      clutter_frame_clock_record_flip (frame_clock,
-+                                       g_get_monotonic_time (),
-+                                       clutter_frame_get_hints (frame));
-+    }
- 
-   _clutter_stage_window_finish_frame (stage_window, view, frame);
- 
+From 6a87d89aff36d62b2a062f437b664cae7ea278bb Mon Sep 17 00:00:00 2001
+From: Daniel van Vugt <daniel.van.vugt@canonical.com>
+Date: Fri, 17 Sep 2021 17:48:20 +0800
+Subject: [PATCH 01/34] cogl/onscreen: Add function
+ cogl_onscreen_count_pending_frames
+
+---
+ cogl/cogl/cogl-onscreen-private.h | 3 +++
+ cogl/cogl/cogl-onscreen.c         | 8 ++++++++
+ 2 files changed, 11 insertions(+)
+
 diff --git a/cogl/cogl/cogl-onscreen-private.h b/cogl/cogl/cogl-onscreen-private.h
-index 959a60533b3fac8fbe2bf791d3228f54e302fb98..86d8ea2d5ff3dbc15f41627475cd8ebf72057bf3 100644
+index 959a60533..785f67aca 100644
 --- a/cogl/cogl/cogl-onscreen-private.h
 +++ b/cogl/cogl/cogl-onscreen-private.h
-@@ -78,4 +78,7 @@ COGL_EXPORT CoglFrameInfo *
- cogl_onscreen_peek_tail_frame_info (CoglOnscreen *onscreen);
+@@ -79,3 +79,6 @@ cogl_onscreen_peek_tail_frame_info (CoglOnscreen *onscreen);
  
  COGL_EXPORT CoglFrameInfo *
--cogl_onscreen_pop_head_frame_info (CoglOnscreen *onscreen);
-+cogl_onscreen_pop_head_frame_info  (CoglOnscreen *onscreen);
+ cogl_onscreen_pop_head_frame_info (CoglOnscreen *onscreen);
 +
 +COGL_EXPORT unsigned int
 +cogl_onscreen_count_pending_frames (CoglOnscreen *onscreen);
 diff --git a/cogl/cogl/cogl-onscreen.c b/cogl/cogl/cogl-onscreen.c
-index afb648bcd8110979cc6c0dbe21481822660d2e4e..086be7ed7a9292013842516e9428808080c8eaf6 100644
+index afb648bcd..086be7ed7 100644
 --- a/cogl/cogl/cogl-onscreen.c
 +++ b/cogl/cogl/cogl-onscreen.c
 @@ -515,6 +515,14 @@ cogl_onscreen_pop_head_frame_info (CoglOnscreen *onscreen)
@@ -820,38 +55,50 @@ index afb648bcd8110979cc6c0dbe21481822660d2e4e..086be7ed7a9292013842516e94288080
  CoglFrameClosure *
  cogl_onscreen_add_frame_callback (CoglOnscreen *onscreen,
                                    CoglFrameCallback callback,
-diff --git a/src/backends/meta-stage-impl.c b/src/backends/meta-stage-impl.c
-index 7aa24439d73762b82f73b092313582815af45245..727e1a5f30b39b42944eaeeb454226c6402d3a40 100644
---- a/src/backends/meta-stage-impl.c
-+++ b/src/backends/meta-stage-impl.c
-@@ -774,6 +774,8 @@ meta_stage_impl_redraw_view (ClutterStageWindow *stage_window,
-     {
-       g_autoptr (GError) error = NULL;
- 
-+      clutter_frame_set_hint (frame, CLUTTER_FRAME_HINT_DIRECT_SCANOUT_ATTEMPTED);
-+
-       if (meta_stage_impl_scanout_view (stage_impl,
-                                         stage_view,
-                                         scanout,
-diff --git a/src/backends/native/meta-kms-impl-device.c b/src/backends/native/meta-kms-impl-device.c
-index b15eee14d59a47a8913e59861f033a47bcfa1660..05bc89e83720dd551aa7f2f8a0847a3c8c50a792 100644
---- a/src/backends/native/meta-kms-impl-device.c
-+++ b/src/backends/native/meta-kms-impl-device.c
-@@ -1559,9 +1559,11 @@ meta_kms_impl_device_handle_update (MetaKmsImplDevice *impl_device,
-       meta_kms_update_merge_from (crtc_frame->pending_update, update);
-       meta_kms_update_free (update);
-       update = g_steal_pointer (&crtc_frame->pending_update);
--      disarm_crtc_frame_deadline_timer (crtc_frame);
-     }
+-- 
+2.45.0
+
+
+From 9240d40c44519c15f4bde53e4b82aa706f47f923 Mon Sep 17 00:00:00 2001
+From: Daniel van Vugt <daniel.van.vugt@canonical.com>
+Date: Mon, 12 Feb 2024 17:16:03 +0800
+Subject: [PATCH 02/34] cogl/onscreen: Indent declaration parameters to align
+ with above/below
+
+This fixes warnings from check-code-style.
+---
+ cogl/cogl/cogl-onscreen-private.h | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/cogl/cogl/cogl-onscreen-private.h b/cogl/cogl/cogl-onscreen-private.h
+index 785f67aca..86d8ea2d5 100644
+--- a/cogl/cogl/cogl-onscreen-private.h
++++ b/cogl/cogl/cogl-onscreen-private.h
+@@ -78,7 +78,7 @@ COGL_EXPORT CoglFrameInfo *
+ cogl_onscreen_peek_tail_frame_info (CoglOnscreen *onscreen);
  
-+  if (crtc_frame->deadline.armed)
-+    disarm_crtc_frame_deadline_timer (crtc_frame);
-+
-   meta_kms_device_handle_flush (priv->device, latch_crtc);
+ COGL_EXPORT CoglFrameInfo *
+-cogl_onscreen_pop_head_frame_info (CoglOnscreen *onscreen);
++cogl_onscreen_pop_head_frame_info  (CoglOnscreen *onscreen);
  
-   feedback = do_process (impl_device, latch_crtc, update, flags);
+ COGL_EXPORT unsigned int
+ cogl_onscreen_count_pending_frames (CoglOnscreen *onscreen);
+-- 
+2.45.0
+
+
+From 902dee95d123ddc7c479bd7df83175ec8e0f8d0b Mon Sep 17 00:00:00 2001
+From: Daniel van Vugt <daniel.van.vugt@canonical.com>
+Date: Wed, 20 Apr 2022 18:33:43 +0800
+Subject: [PATCH 03/34] kms: Keep a shutting_down flag
+
+---
+ src/backends/native/meta-kms.c | 9 +++++++++
+ src/backends/native/meta-kms.h | 2 ++
+ 2 files changed, 11 insertions(+)
+
 diff --git a/src/backends/native/meta-kms.c b/src/backends/native/meta-kms.c
-index 795008b210fe97f99252c10248f510bee878c24e..70d1e792c4582d51fbd896ee79fab997b0167de1 100644
+index 795008b21..70d1e792c 100644
 --- a/src/backends/native/meta-kms.c
 +++ b/src/backends/native/meta-kms.c
 @@ -63,6 +63,8 @@ struct _MetaKms
@@ -885,7 +132,7 @@ index 795008b210fe97f99252c10248f510bee878c24e..70d1e792c4582d51fbd896ee79fab997
  meta_kms_finalize (GObject *object)
  {
 diff --git a/src/backends/native/meta-kms.h b/src/backends/native/meta-kms.h
-index 74340140639f14a6913dec269f014e7be42d6db0..f6b19520bec5c13b8685bea139a48b13d0478057 100644
+index 743401406..f6b19520b 100644
 --- a/src/backends/native/meta-kms.h
 +++ b/src/backends/native/meta-kms.h
 @@ -60,6 +60,8 @@ MetaKmsDevice * meta_kms_create_device (MetaKms            *kms,
@@ -897,42 +144,252 @@ index 74340140639f14a6913dec269f014e7be42d6db0..f6b19520bec5c13b8685bea139a48b13
  MetaKms * meta_kms_new (MetaBackend   *backend,
                          MetaKmsFlags   flags,
                          GError       **error);
+-- 
+2.45.0
+
+
+From 034de98e76be201ebd5a1b62ecc27b8e6d2f61fa Mon Sep 17 00:00:00 2001
+From: Daniel van Vugt <daniel.van.vugt@canonical.com>
+Date: Tue, 26 Oct 2021 18:50:50 +0800
+Subject: [PATCH 04/34] renderer/native: Avoid requeuing the same onscreen for
+ a power save flip
+
+This is a case that triple buffering will encounter. We don't want it
+to queue the same onscreen multiple times because that would represent
+multiple flips occurring simultaneously.
+
+It's a linear search but the list length is typically only 1 or 2 so
+no need for anything fancier yet.
+---
+ src/backends/native/meta-renderer-native.c | 3 +++
+ 1 file changed, 3 insertions(+)
+
+diff --git a/src/backends/native/meta-renderer-native.c b/src/backends/native/meta-renderer-native.c
+index aa76d018c..770b5ab75 100644
+--- a/src/backends/native/meta-renderer-native.c
++++ b/src/backends/native/meta-renderer-native.c
+@@ -748,6 +748,9 @@ meta_renderer_native_queue_power_save_page_flip (MetaRendererNative *renderer_na
+ {
+   const unsigned int timeout_ms = 100;
+ 
++  if (g_list_find (renderer_native->power_save_page_flip_onscreens, onscreen))
++    return;
++
+   if (!renderer_native->power_save_page_flip_source_id)
+     {
+       renderer_native->power_save_page_flip_source_id =
+-- 
+2.45.0
+
+
+From 6095010970ae6f77c4f1529baf7acad05293b58e Mon Sep 17 00:00:00 2001
+From: Daniel van Vugt <daniel.van.vugt@canonical.com>
+Date: Mon, 1 Nov 2021 19:35:34 +0800
+Subject: [PATCH 05/34] renderer/native: Steal the power save flip list before
+ iterating over it
+
+Because a single iteration might also grow the list again.
+---
+ src/backends/native/meta-renderer-native.c | 10 ++++++++--
+ 1 file changed, 8 insertions(+), 2 deletions(-)
+
+diff --git a/src/backends/native/meta-renderer-native.c b/src/backends/native/meta-renderer-native.c
+index 770b5ab75..601fd674a 100644
+--- a/src/backends/native/meta-renderer-native.c
++++ b/src/backends/native/meta-renderer-native.c
+@@ -731,12 +731,18 @@ static gboolean
+ dummy_power_save_page_flip_cb (gpointer user_data)
+ {
+   MetaRendererNative *renderer_native = user_data;
++  GList *old_list =
++    g_steal_pointer (&renderer_native->power_save_page_flip_onscreens);
+ 
+-  g_list_foreach (renderer_native->power_save_page_flip_onscreens,
++  g_list_foreach (old_list,
+                   (GFunc) meta_onscreen_native_dummy_power_save_page_flip,
+                   NULL);
+-  g_clear_list (&renderer_native->power_save_page_flip_onscreens,
++  g_clear_list (&old_list,
+                 g_object_unref);
++
++  if (renderer_native->power_save_page_flip_onscreens != NULL)
++    return G_SOURCE_CONTINUE;
++
+   renderer_native->power_save_page_flip_source_id = 0;
+ 
+   return G_SOURCE_REMOVE;
+-- 
+2.45.0
+
+
+From 581de2f7ee384615545456f00f2e5c0f100c2619 Mon Sep 17 00:00:00 2001
+From: Daniel van Vugt <daniel.van.vugt@canonical.com>
+Date: Fri, 10 Dec 2021 16:40:58 +0800
+Subject: [PATCH 06/34] onscreen/native: Log swapbuffers and N-buffering when
+ MUTTER_DEBUG=kms
+
+---
+ src/backends/native/meta-onscreen-native.c | 13 +++++++++++++
+ 1 file changed, 13 insertions(+)
+
 diff --git a/src/backends/native/meta-onscreen-native.c b/src/backends/native/meta-onscreen-native.c
-index 1a31f04a164d9acf05523555cb2f515b23a526cc..9836663d0c7f481d82c8715f1d856a0662a3218a 100644
+index 1a31f04a1..2b57731be 100644
 --- a/src/backends/native/meta-onscreen-native.c
 +++ b/src/backends/native/meta-onscreen-native.c
-@@ -76,7 +76,7 @@ typedef struct _MetaOnscreenNativeSecondaryGpuState
+@@ -1305,6 +1305,19 @@ meta_onscreen_native_swap_buffers_with_damage (CoglOnscreen  *onscreen,
+   COGL_TRACE_BEGIN_SCOPED (MetaRendererNativeSwapBuffers,
+                            "Meta::OnscreenNative::swap_buffers_with_damage()");
  
-   struct {
-     MetaDrmBufferDumb *current_dumb_fb;
--    MetaDrmBufferDumb *dumb_fbs[2];
-+    MetaDrmBufferDumb *dumb_fbs[3];
-   } cpu;
++  if (meta_is_topic_enabled (META_DEBUG_KMS))
++    {
++      unsigned int frames_pending =
++        cogl_onscreen_count_pending_frames (onscreen);
++
++      meta_topic (META_DEBUG_KMS,
++                  "Swap buffers: %u frames pending (%s-buffering)",
++                  frames_pending,
++                  frames_pending == 1 ? "double" :
++                  frames_pending == 2 ? "triple" :
++                  "?");
++    }
++
+   secondary_gpu_fb =
+     update_secondary_gpu_state_pre_swap_buffers (onscreen,
+                                                  rectangles,
+-- 
+2.45.0
+
+
+From 17f101b17d367fd1d5c75eaec617101b0ec605e6 Mon Sep 17 00:00:00 2001
+From: Daniel van Vugt <daniel.van.vugt@canonical.com>
+Date: Wed, 28 Jul 2021 16:35:56 +0800
+Subject: [PATCH 07/34] onscreen/native: Replace an assertion that double
+ buffering is the maximum
+
+Because it soon won't be the maximum. But we do want to verify that the
+frame info queue is not empty, to avoid NULL dereferencing and catch logic
+errors.
+---
+ src/backends/native/meta-onscreen-native.c | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/src/backends/native/meta-onscreen-native.c b/src/backends/native/meta-onscreen-native.c
+index 2b57731be..dbc503ebf 100644
+--- a/src/backends/native/meta-onscreen-native.c
++++ b/src/backends/native/meta-onscreen-native.c
+@@ -207,7 +207,7 @@ meta_onscreen_native_notify_frame_complete (CoglOnscreen *onscreen)
  
-   gboolean noted_primary_gpu_copy_ok;
-@@ -98,9 +98,13 @@ struct _MetaOnscreenNative
-   struct {
-     struct gbm_surface *surface;
-     MetaDrmBuffer *current_fb;
-+    MetaDrmBuffer *posted_fb;
-     MetaDrmBuffer *next_fb;
-+    MetaDrmBuffer *stalled_fb;
-     CoglScanout *current_scanout;
-+    CoglScanout *posted_scanout;
-     CoglScanout *next_scanout;
-+    CoglScanout *stalled_scanout;
-   } gbm;
+   info = cogl_onscreen_pop_head_frame_info (onscreen);
  
- #ifdef HAVE_EGL_DEVICE
-@@ -125,6 +129,16 @@ struct _MetaOnscreenNative
+-  g_assert (!cogl_onscreen_peek_head_frame_info (onscreen));
++  g_return_if_fail (info);
+ 
+   _cogl_onscreen_notify_frame_sync (onscreen, info);
+   _cogl_onscreen_notify_complete (onscreen, info);
+-- 
+2.45.0
+
+
+From e7754b38c77ff88da16af8361851563ed2e9ea61 Mon Sep 17 00:00:00 2001
+From: Daniel van Vugt <daniel.van.vugt@canonical.com>
+Date: Thu, 16 Sep 2021 16:26:25 +0800
+Subject: [PATCH 08/34] onscreen/native: Deduplicate calls to
+ clutter_frame_set_result
+
+All paths out of `meta_onscreen_native_swap_buffers_with_damage` from
+here onward would set the same `CLUTTER_FRAME_RESULT_PENDING_PRESENTED`
+(or terminate with `g_assert_not_reached`).
+
+Even failed posts set this result because they will do a
+`meta_onscreen_native_notify_frame_complete` in
+`page_flip_feedback_discarded`.
+---
+ src/backends/native/meta-onscreen-native.c | 12 +++---------
+ 1 file changed, 3 insertions(+), 9 deletions(-)
+
+diff --git a/src/backends/native/meta-onscreen-native.c b/src/backends/native/meta-onscreen-native.c
+index dbc503ebf..06f9e81e8 100644
+--- a/src/backends/native/meta-onscreen-native.c
++++ b/src/backends/native/meta-onscreen-native.c
+@@ -1417,6 +1417,9 @@ meta_onscreen_native_swap_buffers_with_damage (CoglOnscreen  *onscreen,
+ #endif
+     }
+ 
++  clutter_frame_set_result (frame,
++                            CLUTTER_FRAME_RESULT_PENDING_PRESENTED);
++
+   /*
+    * If we changed EGL context, cogl will have the wrong idea about what is
+    * current, making it fail to set it when it needs to. Avoid that by making
+@@ -1453,8 +1456,6 @@ meta_onscreen_native_swap_buffers_with_damage (CoglOnscreen  *onscreen,
+     {
+       meta_renderer_native_queue_power_save_page_flip (renderer_native,
+                                                        onscreen);
+-      clutter_frame_set_result (frame,
+-                                CLUTTER_FRAME_RESULT_PENDING_PRESENTED);
+       return;
+     }
+ 
+@@ -1474,8 +1475,6 @@ meta_onscreen_native_swap_buffers_with_damage (CoglOnscreen  *onscreen,
+           kms_update = meta_frame_native_steal_kms_update (frame_native);
+           meta_renderer_native_queue_mode_set_update (renderer_native,
+                                                       kms_update);
+-          clutter_frame_set_result (frame,
+-                                    CLUTTER_FRAME_RESULT_PENDING_PRESENTED);
+           return;
+         }
+       else if (meta_renderer_native_has_pending_mode_set (renderer_native))
+@@ -1489,8 +1488,6 @@ meta_onscreen_native_swap_buffers_with_damage (CoglOnscreen  *onscreen,
+ 
+           meta_frame_native_steal_kms_update (frame_native);
+           meta_renderer_native_post_mode_set_updates (renderer_native);
+-          clutter_frame_set_result (frame,
+-                                    CLUTTER_FRAME_RESULT_PENDING_PRESENTED);
+           return;
+         }
+       break;
+@@ -1506,8 +1503,6 @@ meta_onscreen_native_swap_buffers_with_damage (CoglOnscreen  *onscreen,
+                                                       kms_update);
+ 
+           meta_renderer_native_post_mode_set_updates (renderer_native);
+-          clutter_frame_set_result (frame,
+-                                    CLUTTER_FRAME_RESULT_PENDING_PRESENTED);
+           return;
+         }
+       break;
+@@ -1522,7 +1517,6 @@ meta_onscreen_native_swap_buffers_with_damage (CoglOnscreen  *onscreen,
+   kms_update = meta_frame_native_steal_kms_update (frame_native);
+   meta_kms_device_post_update (kms_device, kms_update,
+                                META_KMS_UPDATE_FLAG_NONE);
+-  clutter_frame_set_result (frame, CLUTTER_FRAME_RESULT_PENDING_PRESENTED);
+ }
+ 
+ gboolean
+-- 
+2.45.0
+
+
+From 42e23ce307b06eac156ef7877603427862f9f4a2 Mon Sep 17 00:00:00 2001
+From: Daniel van Vugt <daniel.van.vugt@canonical.com>
+Date: Wed, 28 Jul 2021 16:29:27 +0800
+Subject: [PATCH 09/34] onscreen/native: Split swap_buffers_with_damage into
+ two functions
+
+1. The EGL part: meta_onscreen_native_swap_buffers_with_damage
+2. The KMS part: post_latest_swap
+---
+ src/backends/native/meta-onscreen-native.c | 66 +++++++++++++++++-----
+ 1 file changed, 53 insertions(+), 13 deletions(-)
+
+diff --git a/src/backends/native/meta-onscreen-native.c b/src/backends/native/meta-onscreen-native.c
+index 06f9e81e8..524bc393d 100644
+--- a/src/backends/native/meta-onscreen-native.c
++++ b/src/backends/native/meta-onscreen-native.c
+@@ -125,6 +125,12 @@ struct _MetaOnscreenNative
    gulong privacy_screen_changed_handler_id;
    gulong color_space_changed_handler_id;
    gulong hdr_metadata_changed_handler_id;
 +
-+  gboolean needs_flush;
-+
-+  unsigned int swaps_pending;
-+
 +  struct {
 +    int *rectangles;  /* 4 x n_rectangles */
 +    int n_rectangles;
@@ -941,20 +398,189 @@ index 1a31f04a164d9acf05523555cb2f515b23a526cc..9836663d0c7f481d82c8715f1d856a06
  };
  
  G_DEFINE_TYPE (MetaOnscreenNative, meta_onscreen_native,
-@@ -132,44 +146,42 @@ G_DEFINE_TYPE (MetaOnscreenNative, meta_onscreen_native,
+@@ -132,6 +138,9 @@ G_DEFINE_TYPE (MetaOnscreenNative, meta_onscreen_native,
  
  static GQuark blit_source_quark = 0;
  
 +static void
-+try_post_latest_swap (CoglOnscreen *onscreen);
-+
-+static void
-+post_finish_frame (MetaOnscreenNative *onscreen_native,
-+                   MetaKmsUpdate      *kms_update);
++post_latest_swap (CoglOnscreen *onscreen);
 +
  static gboolean
  init_secondary_gpu_state (MetaRendererNative  *renderer_native,
                            CoglOnscreen        *onscreen,
+@@ -1279,28 +1288,20 @@ meta_onscreen_native_swap_buffers_with_damage (CoglOnscreen  *onscreen,
+   CoglRendererEGL *cogl_renderer_egl = cogl_renderer->winsys;
+   MetaRendererNativeGpuData *renderer_gpu_data = cogl_renderer_egl->platform;
+   MetaRendererNative *renderer_native = renderer_gpu_data->renderer_native;
+-  MetaRenderer *renderer = META_RENDERER (renderer_native);
+-  MetaBackend *backend = meta_renderer_get_backend (renderer);
+-  MetaMonitorManager *monitor_manager =
+-    meta_backend_get_monitor_manager (backend);
+   MetaOnscreenNative *onscreen_native = META_ONSCREEN_NATIVE (onscreen);
+   MetaOnscreenNativeSecondaryGpuState *secondary_gpu_state;
+   MetaGpuKms *render_gpu = onscreen_native->render_gpu;
+   MetaDeviceFile *render_device_file;
+   ClutterFrame *frame = user_data;
+-  MetaFrameNative *frame_native = meta_frame_native_from_frame (frame);
+-  MetaKmsUpdate *kms_update;
+   CoglOnscreenClass *parent_class;
+   gboolean create_timestamp_query = TRUE;
+   gboolean egl_context_changed = FALSE;
+-  MetaPowerSave power_save_mode;
+   g_autoptr (GError) error = NULL;
+   MetaDrmBufferFlags buffer_flags;
+   MetaDrmBufferGbm *buffer_gbm;
+   g_autoptr (MetaDrmBuffer) primary_gpu_fb = NULL;
+   g_autoptr (MetaDrmBuffer) secondary_gpu_fb = NULL;
+-  MetaKmsCrtc *kms_crtc;
+-  MetaKmsDevice *kms_device;
++  size_t rectangles_size;
+ 
+   COGL_TRACE_BEGIN_SCOPED (MetaRendererNativeSwapBuffers,
+                            "Meta::OnscreenNative::swap_buffers_with_damage()");
+@@ -1429,12 +1430,47 @@ meta_onscreen_native_swap_buffers_with_damage (CoglOnscreen  *onscreen,
+   if (egl_context_changed)
+     _cogl_winsys_egl_ensure_current (cogl_display);
+ 
+-  kms_crtc = meta_crtc_kms_get_kms_crtc (META_CRTC_KMS (onscreen_native->crtc));
+-  kms_device = meta_kms_crtc_get_device (kms_crtc);
++  rectangles_size = n_rectangles * 4 * sizeof (int);
++  onscreen_native->next_post.rectangles =
++    g_realloc (onscreen_native->next_post.rectangles, rectangles_size);
++  memcpy (onscreen_native->next_post.rectangles, rectangles, rectangles_size);
++  onscreen_native->next_post.n_rectangles = n_rectangles;
++
++  g_clear_pointer (&onscreen_native->next_post.frame, clutter_frame_unref);
++  onscreen_native->next_post.frame = clutter_frame_ref (frame);
++
++  post_latest_swap (onscreen);
++}
++
++static void
++post_latest_swap (CoglOnscreen *onscreen)
++{
++  CoglFramebuffer *framebuffer = COGL_FRAMEBUFFER (onscreen);
++  CoglContext *cogl_context = cogl_framebuffer_get_context (framebuffer);
++  CoglRenderer *cogl_renderer = cogl_context->display->renderer;
++  CoglRendererEGL *cogl_renderer_egl = cogl_renderer->winsys;
++  MetaRendererNativeGpuData *renderer_gpu_data = cogl_renderer_egl->platform;
++  MetaRendererNative *renderer_native = renderer_gpu_data->renderer_native;
++  MetaRenderer *renderer = META_RENDERER (renderer_native);
++  MetaBackend *backend = meta_renderer_get_backend (renderer);
++  MetaMonitorManager *monitor_manager =
++    meta_backend_get_monitor_manager (backend);
++  MetaOnscreenNative *onscreen_native = META_ONSCREEN_NATIVE (onscreen);
++  MetaPowerSave power_save_mode;
++  MetaCrtcKms *crtc_kms = META_CRTC_KMS (onscreen_native->crtc);
++  MetaKmsCrtc *kms_crtc = meta_crtc_kms_get_kms_crtc (crtc_kms);
++  MetaKmsDevice *kms_device = meta_kms_crtc_get_device (kms_crtc);
++  MetaKmsUpdate *kms_update;
++  g_autoptr (MetaKmsFeedback) kms_feedback = NULL;
++  g_autoptr (ClutterFrame) frame =
++    g_steal_pointer (&onscreen_native->next_post.frame);
++  MetaFrameNative *frame_native;
+ 
+   power_save_mode = meta_monitor_manager_get_power_save_mode (monitor_manager);
+   if (power_save_mode == META_POWER_SAVE_ON)
+     {
++      frame_native = meta_frame_native_from_frame (frame);
++
+       kms_update = meta_frame_native_ensure_kms_update (frame_native,
+                                                         kms_device);
+       meta_kms_update_add_result_listener (kms_update,
+@@ -1449,8 +1485,8 @@ meta_onscreen_native_swap_buffers_with_damage (CoglOnscreen  *onscreen,
+                                       onscreen_native->crtc,
+                                       kms_update,
+                                       META_KMS_ASSIGN_PLANE_FLAG_NONE,
+-                                      rectangles,
+-                                      n_rectangles);
++                                      onscreen_native->next_post.rectangles,
++                                      onscreen_native->next_post.n_rectangles);
+     }
+   else
+     {
+@@ -2872,6 +2908,10 @@ meta_onscreen_native_dispose (GObject *object)
+ 
+   g_clear_object (&onscreen_native->output);
+   g_clear_object (&onscreen_native->crtc);
++
++  g_clear_pointer (&onscreen_native->next_post.rectangles, g_free);
++  g_clear_pointer (&onscreen_native->next_post.frame, clutter_frame_unref);
++  onscreen_native->next_post.n_rectangles = 0;
+ }
+ 
+ static void
+-- 
+2.45.0
+
+
+From db2680938786f83147215c6ac2ceddc3ea805ab9 Mon Sep 17 00:00:00 2001
+From: Daniel van Vugt <daniel.van.vugt@canonical.com>
+Date: Thu, 28 Oct 2021 17:24:11 +0800
+Subject: [PATCH 10/34] onscreen/native: Add a missing frame notification
+
+In the unlikely event that swap_buffers_with_damage drops the previous swap
+it was forgetting to notify about the discarded frame. That could lead to
+frame clock freezes.
+---
+ src/backends/native/meta-onscreen-native.c | 9 +++++++++
+ 1 file changed, 9 insertions(+)
+
+diff --git a/src/backends/native/meta-onscreen-native.c b/src/backends/native/meta-onscreen-native.c
+index 524bc393d..eaa00d45a 100644
+--- a/src/backends/native/meta-onscreen-native.c
++++ b/src/backends/native/meta-onscreen-native.c
+@@ -1394,6 +1394,15 @@ meta_onscreen_native_swap_buffers_with_damage (CoglOnscreen  *onscreen,
+     {
+     case META_RENDERER_NATIVE_MODE_GBM:
+       g_warn_if_fail (onscreen_native->gbm.next_fb == NULL);
++      if (onscreen_native->gbm.next_fb != NULL)
++        {
++          CoglFrameInfo *frame_info;
++
++          frame_info = cogl_onscreen_peek_head_frame_info (onscreen);
++          frame_info->flags |= COGL_FRAME_INFO_FLAG_SYMBOLIC;
++          meta_onscreen_native_notify_frame_complete (onscreen);
++        }
++
+       if (onscreen_native->secondary_gpu_state)
+         g_set_object (&onscreen_native->gbm.next_fb, secondary_gpu_fb);
+       else
+-- 
+2.45.0
+
+
+From dfa3cd632df4e2856855d7b8ae8ee557466e24bf Mon Sep 17 00:00:00 2001
+From: Daniel van Vugt <daniel.van.vugt@canonical.com>
+Date: Tue, 5 Dec 2023 17:50:44 +0800
+Subject: [PATCH 11/34] onscreen/native: Insert a 'posted' frame between 'next'
+ and 'current'
+
+This will allow us to keep track of up to two buffers that have been
+swapped but not yet scanning out, for triple buffering.
+
+This commit replaces mutter!1968.
+---
+ src/backends/native/meta-onscreen-native.c | 58 ++++++++++++----------
+ 1 file changed, 31 insertions(+), 27 deletions(-)
+
+diff --git a/src/backends/native/meta-onscreen-native.c b/src/backends/native/meta-onscreen-native.c
+index eaa00d45a..2617b1606 100644
+--- a/src/backends/native/meta-onscreen-native.c
++++ b/src/backends/native/meta-onscreen-native.c
+@@ -98,8 +98,10 @@ struct _MetaOnscreenNative
+   struct {
+     struct gbm_surface *surface;
+     MetaDrmBuffer *current_fb;
++    MetaDrmBuffer *posted_fb;
+     MetaDrmBuffer *next_fb;
+     CoglScanout *current_scanout;
++    CoglScanout *posted_scanout;
+     CoglScanout *next_scanout;
+   } gbm;
+ 
+@@ -146,39 +148,30 @@ init_secondary_gpu_state (MetaRendererNative  *renderer_native,
+                           CoglOnscreen        *onscreen,
                            GError             **error);
  
 -static void
@@ -1002,16 +628,139 @@ index 1a31f04a164d9acf05523555cb2f515b23a526cc..9836663d0c7f481d82c8715f1d856a06
  }
  
  static void
-@@ -207,7 +219,7 @@ meta_onscreen_native_notify_frame_complete (CoglOnscreen *onscreen)
+@@ -359,7 +352,7 @@ page_flip_feedback_discarded (MetaKmsCrtc  *kms_crtc,
+   frame_info->flags |= COGL_FRAME_INFO_FLAG_SYMBOLIC;
  
-   info = cogl_onscreen_pop_head_frame_info (onscreen);
+   meta_onscreen_native_notify_frame_complete (onscreen);
+-  meta_onscreen_native_clear_next_fb (onscreen);
++  meta_onscreen_native_clear_posted_fb (onscreen);
+ }
  
--  g_assert (!cogl_onscreen_peek_head_frame_info (onscreen));
-+  g_return_if_fail (info);
+ static const MetaKmsPageFlipListenerVtable page_flip_listener_vtable = {
+@@ -530,13 +523,21 @@ meta_onscreen_native_flip_crtc (CoglOnscreen           *onscreen,
+   switch (renderer_gpu_data->mode)
+     {
+     case META_RENDERER_NATIVE_MODE_GBM:
+-      buffer = onscreen_native->gbm.next_fb;
++      g_set_object (&onscreen_native->gbm.posted_fb,
++                    onscreen_native->gbm.next_fb);
++      g_clear_object (&onscreen_native->gbm.next_fb);
++
++      buffer = onscreen_native->gbm.posted_fb;
++
++      g_set_object (&onscreen_native->gbm.posted_scanout,
++                    onscreen_native->gbm.next_scanout);
++      g_clear_object (&onscreen_native->gbm.next_scanout);
  
-   _cogl_onscreen_notify_frame_sync (onscreen, info);
-   _cogl_onscreen_notify_complete (onscreen, info);
-@@ -243,6 +255,7 @@ notify_view_crtc_presented (MetaRendererView *view,
+-      if (onscreen_native->gbm.next_scanout)
++      if (onscreen_native->gbm.posted_scanout)
+         {
+-          cogl_scanout_get_src_rect (onscreen_native->gbm.next_scanout,
++          cogl_scanout_get_src_rect (onscreen_native->gbm.posted_scanout,
+                                      &src_rect);
+-          cogl_scanout_get_dst_rect (onscreen_native->gbm.next_scanout,
++          cogl_scanout_get_dst_rect (onscreen_native->gbm.posted_scanout,
+                                      &dst_rect);
+         }
+       else
+@@ -1267,7 +1268,7 @@ swap_buffer_result_feedback (const MetaKmsFeedback *kms_feedback,
+   frame_info->flags |= COGL_FRAME_INFO_FLAG_SYMBOLIC;
+ 
+   meta_onscreen_native_notify_frame_complete (onscreen);
+-  meta_onscreen_native_clear_next_fb (onscreen);
++  meta_onscreen_native_clear_posted_fb (onscreen);
+ }
+ 
+ static const MetaKmsResultListenerVtable swap_buffer_result_listener_vtable = {
+@@ -1632,7 +1633,7 @@ scanout_result_feedback (const MetaKmsFeedback *kms_feedback,
+ 
+       g_warning ("Direct scanout page flip failed: %s", error->message);
+ 
+-      cogl_scanout_notify_failed (onscreen_native->gbm.next_scanout,
++      cogl_scanout_notify_failed (onscreen_native->gbm.posted_scanout,
+                                   onscreen);
+       clutter_stage_view_add_redraw_clip (view, NULL);
+       clutter_stage_view_schedule_update_now (view);
+@@ -1642,7 +1643,7 @@ scanout_result_feedback (const MetaKmsFeedback *kms_feedback,
+   frame_info->flags |= COGL_FRAME_INFO_FLAG_SYMBOLIC;
+ 
+   meta_onscreen_native_notify_frame_complete (onscreen);
+-  meta_onscreen_native_clear_next_fb (onscreen);
++  meta_onscreen_native_clear_posted_fb (onscreen);
+ }
+ 
+ static const MetaKmsResultListenerVtable scanout_result_listener_vtable = {
+@@ -2882,8 +2883,11 @@ meta_onscreen_native_dispose (GObject *object)
+     {
+     case META_RENDERER_NATIVE_MODE_GBM:
+       g_clear_object (&onscreen_native->gbm.next_fb);
++      g_clear_object (&onscreen_native->gbm.posted_fb);
++      g_clear_object (&onscreen_native->gbm.current_fb);
+       g_clear_object (&onscreen_native->gbm.next_scanout);
+-      free_current_bo (onscreen);
++      g_clear_object (&onscreen_native->gbm.posted_scanout);
++      g_clear_object (&onscreen_native->gbm.current_scanout);
+       break;
+     case META_RENDERER_NATIVE_MODE_SURFACELESS:
+       g_assert_not_reached ();
+-- 
+2.45.0
+
+
+From 4c18c898c9bb06855da10b451dae960939cebda9 Mon Sep 17 00:00:00 2001
+From: Daniel van Vugt <daniel.van.vugt@canonical.com>
+Date: Fri, 17 Sep 2021 17:59:28 +0800
+Subject: [PATCH 12/34] onscreen/native: Defer posting if there's already a
+ post in progress
+
+And when the number of pending posts decreases we know it's safe to submit
+a new one. Since KMS generally only supports one outstanding post right now,
+"decreases" means equal to zero.
+---
+ src/backends/native/meta-onscreen-native.c | 192 ++++++++++++++++++---
+ 1 file changed, 164 insertions(+), 28 deletions(-)
+
+diff --git a/src/backends/native/meta-onscreen-native.c b/src/backends/native/meta-onscreen-native.c
+index 2617b1606..d57aad0b2 100644
+--- a/src/backends/native/meta-onscreen-native.c
++++ b/src/backends/native/meta-onscreen-native.c
+@@ -100,9 +100,11 @@ struct _MetaOnscreenNative
+     MetaDrmBuffer *current_fb;
+     MetaDrmBuffer *posted_fb;
+     MetaDrmBuffer *next_fb;
++    MetaDrmBuffer *stalled_fb;
+     CoglScanout *current_scanout;
+     CoglScanout *posted_scanout;
+     CoglScanout *next_scanout;
++    CoglScanout *stalled_scanout;
+   } gbm;
+ 
+ #ifdef HAVE_EGL_DEVICE
+@@ -128,6 +130,10 @@ struct _MetaOnscreenNative
+   gulong color_space_changed_handler_id;
+   gulong hdr_metadata_changed_handler_id;
+ 
++  gboolean needs_flush;
++
++  unsigned int swaps_pending;
++
+   struct {
+     int *rectangles;  /* 4 x n_rectangles */
+     int n_rectangles;
+@@ -141,7 +147,11 @@ G_DEFINE_TYPE (MetaOnscreenNative, meta_onscreen_native,
+ static GQuark blit_source_quark = 0;
+ 
+ static void
+-post_latest_swap (CoglOnscreen *onscreen);
++try_post_latest_swap (CoglOnscreen *onscreen);
++
++static void
++post_finish_frame (MetaOnscreenNative *onscreen_native,
++                   MetaKmsUpdate      *kms_update);
+ 
+ static gboolean
+ init_secondary_gpu_state (MetaRendererNative  *renderer_native,
+@@ -245,6 +255,7 @@ notify_view_crtc_presented (MetaRendererView *view,
  
    meta_onscreen_native_notify_frame_complete (onscreen);
    meta_onscreen_native_swap_drm_fb (onscreen);
@@ -1019,7 +768,7 @@ index 1a31f04a164d9acf05523555cb2f515b23a526cc..9836663d0c7f481d82c8715f1d856a06
  }
  
  static void
-@@ -292,15 +305,13 @@ page_flip_feedback_ready (MetaKmsCrtc *kms_crtc,
+@@ -294,15 +305,13 @@ page_flip_feedback_ready (MetaKmsCrtc *kms_crtc,
    CoglFramebuffer *framebuffer =
      clutter_stage_view_get_onscreen (CLUTTER_STAGE_VIEW (view));
    CoglOnscreen *onscreen = COGL_ONSCREEN (framebuffer);
@@ -1036,17 +785,15 @@ index 1a31f04a164d9acf05523555cb2f515b23a526cc..9836663d0c7f481d82c8715f1d856a06
  }
  
  static void
-@@ -350,7 +361,8 @@ page_flip_feedback_discarded (MetaKmsCrtc  *kms_crtc,
-   frame_info->flags |= COGL_FRAME_INFO_FLAG_SYMBOLIC;
+@@ -353,6 +362,7 @@ page_flip_feedback_discarded (MetaKmsCrtc  *kms_crtc,
  
    meta_onscreen_native_notify_frame_complete (onscreen);
--  meta_onscreen_native_clear_next_fb (onscreen);
-+  meta_onscreen_native_clear_posted_fb (onscreen);
+   meta_onscreen_native_clear_posted_fb (onscreen);
 +  try_post_latest_swap (onscreen);
  }
  
  static const MetaKmsPageFlipListenerVtable page_flip_listener_vtable = {
-@@ -411,18 +423,41 @@ custom_egl_stream_page_flip (gpointer custom_page_flip_data,
+@@ -413,18 +423,41 @@ custom_egl_stream_page_flip (gpointer custom_page_flip_data,
  }
  #endif /* HAVE_EGL_DEVICE */
  
@@ -1091,62 +838,13 @@ index 1a31f04a164d9acf05523555cb2f515b23a526cc..9836663d0c7f481d82c8715f1d856a06
  static void
  apply_transform (MetaCrtcKms            *crtc_kms,
                   MetaKmsPlaneAssignment *kms_plane_assignment,
-@@ -521,13 +556,21 @@ meta_onscreen_native_flip_crtc (CoglOnscreen           *onscreen,
-   switch (renderer_gpu_data->mode)
-     {
-     case META_RENDERER_NATIVE_MODE_GBM:
--      buffer = onscreen_native->gbm.next_fb;
-+      g_set_object (&onscreen_native->gbm.posted_fb,
-+                    onscreen_native->gbm.next_fb);
-+      g_clear_object (&onscreen_native->gbm.next_fb);
-+
-+      buffer = onscreen_native->gbm.posted_fb;
- 
--      if (onscreen_native->gbm.next_scanout)
-+      g_set_object (&onscreen_native->gbm.posted_scanout,
-+                    onscreen_native->gbm.next_scanout);
-+      g_clear_object (&onscreen_native->gbm.next_scanout);
-+
-+      if (onscreen_native->gbm.posted_scanout)
-         {
--          cogl_scanout_get_src_rect (onscreen_native->gbm.next_scanout,
-+          cogl_scanout_get_src_rect (onscreen_native->gbm.posted_scanout,
-                                      &src_rect);
--          cogl_scanout_get_dst_rect (onscreen_native->gbm.next_scanout,
-+          cogl_scanout_get_dst_rect (onscreen_native->gbm.posted_scanout,
-                                      &dst_rect);
-         }
-       else
-@@ -918,12 +961,17 @@ static MetaDrmBufferDumb *
- secondary_gpu_get_next_dumb_buffer (MetaOnscreenNativeSecondaryGpuState *secondary_gpu_state)
- {
-   MetaDrmBufferDumb *current_dumb_fb;
-+  const int n_dumb_fbs = G_N_ELEMENTS (secondary_gpu_state->cpu.dumb_fbs);
-+  int i;
- 
-   current_dumb_fb = secondary_gpu_state->cpu.current_dumb_fb;
--  if (current_dumb_fb == secondary_gpu_state->cpu.dumb_fbs[0])
--    return secondary_gpu_state->cpu.dumb_fbs[1];
--  else
--    return secondary_gpu_state->cpu.dumb_fbs[0];
-+  for (i = 0; i < n_dumb_fbs; i++)
-+    {
-+      if (current_dumb_fb == secondary_gpu_state->cpu.dumb_fbs[i])
-+        return secondary_gpu_state->cpu.dumb_fbs[(i + 1) % n_dumb_fbs];
-+    }
-+
-+  return secondary_gpu_state->cpu.dumb_fbs[0];
- }
- 
- static MetaDrmBuffer *
-@@ -1255,10 +1303,17 @@ swap_buffer_result_feedback (const MetaKmsFeedback *kms_feedback,
+@@ -1265,9 +1298,16 @@ swap_buffer_result_feedback (const MetaKmsFeedback *kms_feedback,
      g_warning ("Page flip failed: %s", error->message);
  
    frame_info = cogl_onscreen_peek_head_frame_info (onscreen);
 -  frame_info->flags |= COGL_FRAME_INFO_FLAG_SYMBOLIC;
  
 -  meta_onscreen_native_notify_frame_complete (onscreen);
--  meta_onscreen_native_clear_next_fb (onscreen);
 +  /* After resuming from suspend, drop_stalled_swap might have done this
 +   * already and emptied the frame_info queue.
 +   */
@@ -1156,64 +854,21 @@ index 1a31f04a164d9acf05523555cb2f515b23a526cc..9836663d0c7f481d82c8715f1d856a06
 +      meta_onscreen_native_notify_frame_complete (onscreen);
 +    }
 +
-+  meta_onscreen_native_clear_posted_fb (onscreen);
+   meta_onscreen_native_clear_posted_fb (onscreen);
  }
  
- static const MetaKmsResultListenerVtable swap_buffer_result_listener_vtable = {
-@@ -1279,32 +1334,37 @@ meta_onscreen_native_swap_buffers_with_damage (CoglOnscreen  *onscreen,
-   CoglRendererEGL *cogl_renderer_egl = cogl_renderer->winsys;
-   MetaRendererNativeGpuData *renderer_gpu_data = cogl_renderer_egl->platform;
-   MetaRendererNative *renderer_native = renderer_gpu_data->renderer_native;
--  MetaRenderer *renderer = META_RENDERER (renderer_native);
--  MetaBackend *backend = meta_renderer_get_backend (renderer);
--  MetaMonitorManager *monitor_manager =
--    meta_backend_get_monitor_manager (backend);
-   MetaOnscreenNative *onscreen_native = META_ONSCREEN_NATIVE (onscreen);
-   MetaOnscreenNativeSecondaryGpuState *secondary_gpu_state;
-   MetaGpuKms *render_gpu = onscreen_native->render_gpu;
-   MetaDeviceFile *render_device_file;
-   ClutterFrame *frame = user_data;
--  MetaFrameNative *frame_native = meta_frame_native_from_frame (frame);
--  MetaKmsUpdate *kms_update;
-   CoglOnscreenClass *parent_class;
-   gboolean create_timestamp_query = TRUE;
-   gboolean egl_context_changed = FALSE;
--  MetaPowerSave power_save_mode;
-   g_autoptr (GError) error = NULL;
-   MetaDrmBufferFlags buffer_flags;
-   MetaDrmBufferGbm *buffer_gbm;
-   g_autoptr (MetaDrmBuffer) primary_gpu_fb = NULL;
-   g_autoptr (MetaDrmBuffer) secondary_gpu_fb = NULL;
--  MetaKmsCrtc *kms_crtc;
--  MetaKmsDevice *kms_device;
-+  size_t rectangles_size;
- 
-   COGL_TRACE_BEGIN_SCOPED (MetaRendererNativeSwapBuffers,
-                            "Meta::OnscreenNative::swap_buffers_with_damage()");
- 
-+  if (meta_is_topic_enabled (META_DEBUG_KMS))
-+    {
-+      unsigned int frames_pending =
-+        cogl_onscreen_count_pending_frames (onscreen);
-+
-+      meta_topic (META_DEBUG_KMS,
-+                  "Swap buffers: %u frames pending (%s-buffering)",
-+                  frames_pending,
-+                  frames_pending == 1 ? "double" :
-+                  frames_pending == 2 ? "triple" :
-+                  "?");
-+    }
-+
-   secondary_gpu_fb =
-     update_secondary_gpu_state_pre_swap_buffers (onscreen,
-                                                  rectangles,
-@@ -1379,7 +1439,17 @@ meta_onscreen_native_swap_buffers_with_damage (CoglOnscreen  *onscreen,
+@@ -1394,14 +1434,15 @@ meta_onscreen_native_swap_buffers_with_damage (CoglOnscreen  *onscreen,
    switch (renderer_gpu_data->mode)
      {
      case META_RENDERER_NATIVE_MODE_GBM:
 -      g_warn_if_fail (onscreen_native->gbm.next_fb == NULL);
-+      if (onscreen_native->gbm.next_fb != NULL)
-+        {
+       if (onscreen_native->gbm.next_fb != NULL)
+         {
+-          CoglFrameInfo *frame_info;
+-
+-          frame_info = cogl_onscreen_peek_head_frame_info (onscreen);
+-          frame_info->flags |= COGL_FRAME_INFO_FLAG_SYMBOLIC;
+-          meta_onscreen_native_notify_frame_complete (onscreen);
 +          g_warn_if_fail (onscreen_native->gbm.stalled_fb == NULL);
 +          drop_stalled_swap (onscreen);
 +          g_assert (onscreen_native->gbm.stalled_fb == NULL);
@@ -1221,70 +876,36 @@ index 1a31f04a164d9acf05523555cb2f515b23a526cc..9836663d0c7f481d82c8715f1d856a06
 +            g_steal_pointer (&onscreen_native->gbm.next_fb);
 +          onscreen_native->gbm.stalled_scanout =
 +            g_steal_pointer (&onscreen_native->gbm.next_scanout);
-+        }
-+
-       if (onscreen_native->secondary_gpu_state)
-         g_set_object (&onscreen_native->gbm.next_fb, secondary_gpu_fb);
-       else
-@@ -1404,6 +1474,9 @@ meta_onscreen_native_swap_buffers_with_damage (CoglOnscreen  *onscreen,
- #endif
-     }
+         }
  
-+  clutter_frame_set_result (frame,
-+                            CLUTTER_FRAME_RESULT_PENDING_PRESENTED);
-+
-   /*
-    * If we changed EGL context, cogl will have the wrong idea about what is
-    * current, making it fail to set it when it needs to. Avoid that by making
-@@ -1413,12 +1486,78 @@ meta_onscreen_native_swap_buffers_with_damage (CoglOnscreen  *onscreen,
-   if (egl_context_changed)
-     _cogl_winsys_egl_ensure_current (cogl_display);
+       if (onscreen_native->secondary_gpu_state)
+@@ -1449,11 +1490,12 @@ meta_onscreen_native_swap_buffers_with_damage (CoglOnscreen  *onscreen,
+   g_clear_pointer (&onscreen_native->next_post.frame, clutter_frame_unref);
+   onscreen_native->next_post.frame = clutter_frame_ref (frame);
  
--  kms_crtc = meta_crtc_kms_get_kms_crtc (META_CRTC_KMS (onscreen_native->crtc));
--  kms_device = meta_kms_crtc_get_device (kms_crtc);
-+  rectangles_size = n_rectangles * 4 * sizeof (int);
-+  onscreen_native->next_post.rectangles =
-+    g_realloc (onscreen_native->next_post.rectangles, rectangles_size);
-+  memcpy (onscreen_native->next_post.rectangles, rectangles, rectangles_size);
-+  onscreen_native->next_post.n_rectangles = n_rectangles;
-+
-+  g_clear_pointer (&onscreen_native->next_post.frame, clutter_frame_unref);
-+  onscreen_native->next_post.frame = clutter_frame_ref (frame);
-+
+-  post_latest_swap (onscreen);
 +  onscreen_native->swaps_pending++;
 +  try_post_latest_swap (onscreen);
-+}
-+
-+static void
+ }
+ 
+ static void
+-post_latest_swap (CoglOnscreen *onscreen)
 +try_post_latest_swap (CoglOnscreen *onscreen)
-+{
-+  CoglFramebuffer *framebuffer = COGL_FRAMEBUFFER (onscreen);
-+  CoglContext *cogl_context = cogl_framebuffer_get_context (framebuffer);
-+  CoglRenderer *cogl_renderer = cogl_context->display->renderer;
-+  CoglRendererEGL *cogl_renderer_egl = cogl_renderer->winsys;
-+  MetaRendererNativeGpuData *renderer_gpu_data = cogl_renderer_egl->platform;
-+  MetaRendererNative *renderer_native = renderer_gpu_data->renderer_native;
-+  MetaRenderer *renderer = META_RENDERER (renderer_native);
-+  MetaBackend *backend = meta_renderer_get_backend (renderer);
-+  MetaBackendNative *backend_native = META_BACKEND_NATIVE (backend);
-+  MetaKms *kms = meta_backend_native_get_kms (backend_native);
-+  MetaMonitorManager *monitor_manager =
-+    meta_backend_get_monitor_manager (backend);
-+  MetaOnscreenNative *onscreen_native = META_ONSCREEN_NATIVE (onscreen);
-+  MetaPowerSave power_save_mode;
-+  MetaCrtcKms *crtc_kms = META_CRTC_KMS (onscreen_native->crtc);
-+  MetaKmsCrtc *kms_crtc = meta_crtc_kms_get_kms_crtc (crtc_kms);
-+  MetaKmsDevice *kms_device = meta_kms_crtc_get_device (kms_crtc);
-+  MetaKmsUpdate *kms_update;
-+  g_autoptr (MetaKmsFeedback) kms_feedback = NULL;
+ {
+   CoglFramebuffer *framebuffer = COGL_FRAMEBUFFER (onscreen);
+   CoglContext *cogl_context = cogl_framebuffer_get_context (framebuffer);
+@@ -1472,15 +1514,41 @@ post_latest_swap (CoglOnscreen *onscreen)
+   MetaKmsDevice *kms_device = meta_kms_crtc_get_device (kms_crtc);
+   MetaKmsUpdate *kms_update;
+   g_autoptr (MetaKmsFeedback) kms_feedback = NULL;
+-  g_autoptr (ClutterFrame) frame =
+-    g_steal_pointer (&onscreen_native->next_post.frame);
 +  g_autoptr (ClutterFrame) frame = NULL;
-+  MetaFrameNative *frame_native;
-+
-+  if (onscreen_native->next_post.frame == NULL ||
-+      onscreen_native->view == NULL ||
-+      meta_kms_is_shutting_down (kms))
-+    return;
+   MetaFrameNative *frame_native;
  
++  if (onscreen_native->next_post.frame == NULL)
++    return;
++
    power_save_mode = meta_monitor_manager_get_power_save_mode (monitor_manager);
    if (power_save_mode == META_POWER_SAVE_ON)
      {
@@ -1298,8 +919,8 @@ index 1a31f04a164d9acf05523555cb2f515b23a526cc..9836663d0c7f481d82c8715f1d856a06
 +        return;  /* wait for the next frame notification and then try again */
 +
 +      frame = g_steal_pointer (&onscreen_native->next_post.frame);
-+      frame_native = meta_frame_native_from_frame (frame);
-+
+       frame_native = meta_frame_native_from_frame (frame);
+ 
 +      if (onscreen_native->swaps_pending == 0)
 +        {
 +          if (frame_native)
@@ -1317,78 +938,7 @@ index 1a31f04a164d9acf05523555cb2f515b23a526cc..9836663d0c7f481d82c8715f1d856a06
        kms_update = meta_frame_native_ensure_kms_update (frame_native,
                                                          kms_device);
        meta_kms_update_add_result_listener (kms_update,
-@@ -1433,15 +1572,13 @@ meta_onscreen_native_swap_buffers_with_damage (CoglOnscreen  *onscreen,
-                                       onscreen_native->crtc,
-                                       kms_update,
-                                       META_KMS_ASSIGN_PLANE_FLAG_NONE,
--                                      rectangles,
--                                      n_rectangles);
-+                                      onscreen_native->next_post.rectangles,
-+                                      onscreen_native->next_post.n_rectangles);
-     }
-   else
-     {
-       meta_renderer_native_queue_power_save_page_flip (renderer_native,
-                                                        onscreen);
--      clutter_frame_set_result (frame,
--                                CLUTTER_FRAME_RESULT_PENDING_PRESENTED);
-       return;
-     }
- 
-@@ -1461,8 +1598,6 @@ meta_onscreen_native_swap_buffers_with_damage (CoglOnscreen  *onscreen,
-           kms_update = meta_frame_native_steal_kms_update (frame_native);
-           meta_renderer_native_queue_mode_set_update (renderer_native,
-                                                       kms_update);
--          clutter_frame_set_result (frame,
--                                    CLUTTER_FRAME_RESULT_PENDING_PRESENTED);
-           return;
-         }
-       else if (meta_renderer_native_has_pending_mode_set (renderer_native))
-@@ -1476,8 +1611,6 @@ meta_onscreen_native_swap_buffers_with_damage (CoglOnscreen  *onscreen,
- 
-           meta_frame_native_steal_kms_update (frame_native);
-           meta_renderer_native_post_mode_set_updates (renderer_native);
--          clutter_frame_set_result (frame,
--                                    CLUTTER_FRAME_RESULT_PENDING_PRESENTED);
-           return;
-         }
-       break;
-@@ -1493,8 +1626,6 @@ meta_onscreen_native_swap_buffers_with_damage (CoglOnscreen  *onscreen,
-                                                       kms_update);
- 
-           meta_renderer_native_post_mode_set_updates (renderer_native);
--          clutter_frame_set_result (frame,
--                                    CLUTTER_FRAME_RESULT_PENDING_PRESENTED);
-           return;
-         }
-       break;
-@@ -1509,7 +1640,6 @@ meta_onscreen_native_swap_buffers_with_damage (CoglOnscreen  *onscreen,
-   kms_update = meta_frame_native_steal_kms_update (frame_native);
-   meta_kms_device_post_update (kms_device, kms_update,
-                                META_KMS_UPDATE_FLAG_NONE);
--  clutter_frame_set_result (frame, CLUTTER_FRAME_RESULT_PENDING_PRESENTED);
- }
- 
- gboolean
-@@ -1580,7 +1710,7 @@ scanout_result_feedback (const MetaKmsFeedback *kms_feedback,
- 
-       g_warning ("Direct scanout page flip failed: %s", error->message);
- 
--      cogl_scanout_notify_failed (onscreen_native->gbm.next_scanout,
-+      cogl_scanout_notify_failed (onscreen_native->gbm.posted_scanout,
-                                   onscreen);
-       clutter_stage_view_add_redraw_clip (view, NULL);
-       clutter_stage_view_schedule_update_now (view);
-@@ -1590,7 +1720,7 @@ scanout_result_feedback (const MetaKmsFeedback *kms_feedback,
-   frame_info->flags |= COGL_FRAME_INFO_FLAG_SYMBOLIC;
- 
-   meta_onscreen_native_notify_frame_complete (onscreen);
--  meta_onscreen_native_clear_next_fb (onscreen);
-+  meta_onscreen_native_clear_posted_fb (onscreen);
- }
- 
- static const MetaKmsResultListenerVtable scanout_result_listener_vtable = {
-@@ -1642,6 +1772,18 @@ meta_onscreen_native_direct_scanout (CoglOnscreen   *onscreen,
+@@ -1695,6 +1763,18 @@ meta_onscreen_native_direct_scanout (CoglOnscreen   *onscreen,
        return FALSE;
      }
  
@@ -1407,19 +957,7 @@ index 1a31f04a164d9acf05523555cb2f515b23a526cc..9836663d0c7f481d82c8715f1d856a06
    renderer_gpu_data = meta_renderer_native_get_gpu_data (renderer_native,
                                                           render_gpu);
  
-@@ -1757,11 +1899,7 @@ meta_onscreen_native_before_redraw (CoglOnscreen *onscreen,
-                                     ClutterFrame *frame)
- {
-   MetaOnscreenNative *onscreen_native = META_ONSCREEN_NATIVE (onscreen);
--  MetaCrtcKms *crtc_kms = META_CRTC_KMS (onscreen_native->crtc);
--  MetaKmsCrtc *kms_crtc = meta_crtc_kms_get_kms_crtc (crtc_kms);
- 
--  meta_kms_device_await_flush (meta_kms_crtc_get_device (kms_crtc),
--                               kms_crtc);
-   maybe_update_frame_sync (onscreen_native, frame);
- }
- 
-@@ -1877,22 +2015,79 @@ meta_onscreen_native_finish_frame (CoglOnscreen *onscreen,
+@@ -1930,22 +2010,79 @@ meta_onscreen_native_finish_frame (CoglOnscreen *onscreen,
    MetaKmsDevice *kms_device = meta_kms_crtc_get_device (kms_crtc);
    MetaFrameNative *frame_native = meta_frame_native_from_frame (frame);
    MetaKmsUpdate *kms_update;
@@ -1507,13 +1045,90 @@ index 1a31f04a164d9acf05523555cb2f515b23a526cc..9836663d0c7f481d82c8715f1d856a06
    meta_kms_update_add_result_listener (kms_update,
                                         &finish_frame_result_listener_vtable,
                                         NULL,
-@@ -1915,7 +2110,19 @@ meta_onscreen_native_finish_frame (CoglOnscreen *onscreen,
+@@ -1968,7 +2105,6 @@ meta_onscreen_native_finish_frame (CoglOnscreen *onscreen,
    meta_kms_update_set_flushing (kms_update, kms_crtc);
    meta_kms_device_post_update (kms_device, kms_update,
                                 META_KMS_UPDATE_FLAG_NONE);
 -  clutter_frame_set_result (frame, CLUTTER_FRAME_RESULT_PENDING_PRESENTED);
-+}
+ }
+ 
+ static gboolean
+-- 
+2.45.0
+
+
+From 24b5694ab79f028933678b8148d43e6a03edb16f Mon Sep 17 00:00:00 2001
+From: Daniel van Vugt <daniel.van.vugt@canonical.com>
+Date: Fri, 9 Dec 2022 14:22:31 +0800
+Subject: [PATCH 13/34] onscreen/native: Increase secondary GPU dumb_fbs from 2
+ to 3
+
+So that they don't get overwritten prematurely during triple buffering
+causing tearing.
+
+https://launchpad.net/bugs/1999216
+---
+ src/backends/native/meta-onscreen-native.c | 15 ++++++++++-----
+ 1 file changed, 10 insertions(+), 5 deletions(-)
+
+diff --git a/src/backends/native/meta-onscreen-native.c b/src/backends/native/meta-onscreen-native.c
+index d57aad0b2..a8e8dcfb7 100644
+--- a/src/backends/native/meta-onscreen-native.c
++++ b/src/backends/native/meta-onscreen-native.c
+@@ -76,7 +76,7 @@ typedef struct _MetaOnscreenNativeSecondaryGpuState
+ 
+   struct {
+     MetaDrmBufferDumb *current_dumb_fb;
+-    MetaDrmBufferDumb *dumb_fbs[2];
++    MetaDrmBufferDumb *dumb_fbs[3];
+   } cpu;
+ 
+   gboolean noted_primary_gpu_copy_ok;
+@@ -961,12 +961,17 @@ static MetaDrmBufferDumb *
+ secondary_gpu_get_next_dumb_buffer (MetaOnscreenNativeSecondaryGpuState *secondary_gpu_state)
+ {
+   MetaDrmBufferDumb *current_dumb_fb;
++  const int n_dumb_fbs = G_N_ELEMENTS (secondary_gpu_state->cpu.dumb_fbs);
++  int i;
+ 
+   current_dumb_fb = secondary_gpu_state->cpu.current_dumb_fb;
+-  if (current_dumb_fb == secondary_gpu_state->cpu.dumb_fbs[0])
+-    return secondary_gpu_state->cpu.dumb_fbs[1];
+-  else
+-    return secondary_gpu_state->cpu.dumb_fbs[0];
++  for (i = 0; i < n_dumb_fbs; i++)
++    {
++      if (current_dumb_fb == secondary_gpu_state->cpu.dumb_fbs[i])
++        return secondary_gpu_state->cpu.dumb_fbs[(i + 1) % n_dumb_fbs];
++    }
 +
++  return secondary_gpu_state->cpu.dumb_fbs[0];
+ }
+ 
+ static MetaDrmBuffer *
+-- 
+2.45.0
+
+
+From a63610a3175bf5cc2202930eef8d1986d2660c7c Mon Sep 17 00:00:00 2001
+From: Daniel van Vugt <daniel.van.vugt@canonical.com>
+Date: Thu, 4 Nov 2021 16:09:26 +0800
+Subject: [PATCH 14/34] onscreen/native: Add function
+ meta_onscreen_native_discard_pending_swaps
+
+---
+ src/backends/native/meta-onscreen-native.c | 13 +++++++++++++
+ src/backends/native/meta-onscreen-native.h |  2 ++
+ 2 files changed, 15 insertions(+)
+
+diff --git a/src/backends/native/meta-onscreen-native.c b/src/backends/native/meta-onscreen-native.c
+index a8e8dcfb7..0c608237c 100644
+--- a/src/backends/native/meta-onscreen-native.c
++++ b/src/backends/native/meta-onscreen-native.c
+@@ -2112,6 +2112,19 @@ post_finish_frame (MetaOnscreenNative *onscreen_native,
+                                META_KMS_UPDATE_FLAG_NONE);
+ }
+ 
 +void
 +meta_onscreen_native_discard_pending_swaps (CoglOnscreen *onscreen)
 +{
@@ -1525,35 +1140,13 @@ index 1a31f04a164d9acf05523555cb2f515b23a526cc..9836663d0c7f481d82c8715f1d856a06
 +  g_clear_object (&onscreen_native->gbm.stalled_scanout);
 +  g_clear_object (&onscreen_native->gbm.next_fb);
 +  g_clear_object (&onscreen_native->gbm.next_scanout);
- }
- 
- static gboolean
-@@ -2830,8 +3037,11 @@ meta_onscreen_native_dispose (GObject *object)
-     {
-     case META_RENDERER_NATIVE_MODE_GBM:
-       g_clear_object (&onscreen_native->gbm.next_fb);
-+      g_clear_object (&onscreen_native->gbm.posted_fb);
-+      g_clear_object (&onscreen_native->gbm.current_fb);
-       g_clear_object (&onscreen_native->gbm.next_scanout);
--      free_current_bo (onscreen);
-+      g_clear_object (&onscreen_native->gbm.posted_scanout);
-+      g_clear_object (&onscreen_native->gbm.current_scanout);
-       break;
-     case META_RENDERER_NATIVE_MODE_SURFACELESS:
-       g_assert_not_reached ();
-@@ -2865,6 +3075,10 @@ meta_onscreen_native_dispose (GObject *object)
- 
-   g_clear_object (&onscreen_native->output);
-   g_clear_object (&onscreen_native->crtc);
++}
 +
-+  g_clear_pointer (&onscreen_native->next_post.rectangles, g_free);
-+  g_clear_pointer (&onscreen_native->next_post.frame, clutter_frame_unref);
-+  onscreen_native->next_post.n_rectangles = 0;
- }
- 
- static void
+ static gboolean
+ should_surface_be_sharable (CoglOnscreen *onscreen)
+ {
 diff --git a/src/backends/native/meta-onscreen-native.h b/src/backends/native/meta-onscreen-native.h
-index 0e1193325a958fadc28e1177d61171fe459f284d..e30357d19d1fd4544026f0f7ef6dba6221d571a9 100644
+index 0e1193325..e30357d19 100644
 --- a/src/backends/native/meta-onscreen-native.h
 +++ b/src/backends/native/meta-onscreen-native.h
 @@ -48,6 +48,8 @@ void meta_onscreen_native_dummy_power_save_page_flip (CoglOnscreen *onscreen);
@@ -1565,42 +1158,80 @@ index 0e1193325a958fadc28e1177d61171fe459f284d..e30357d19d1fd4544026f0f7ef6dba62
  void meta_onscreen_native_set_view (CoglOnscreen     *onscreen,
                                      MetaRendererView *view);
  
+-- 
+2.45.0
+
+
+From 99d1a2d1be42502ab419f947e1aac483c8950000 Mon Sep 17 00:00:00 2001
+From: Daniel van Vugt <daniel.van.vugt@canonical.com>
+Date: Wed, 11 May 2022 16:00:32 +0800
+Subject: [PATCH 15/34] onscreen/native: Skip try_post_latest_swap if shutting
+ down
+
+Otherwise we could get:
+
+  meta_kms_prepare_shutdown ->
+  flush_callbacks ->
+  ... ->
+  try_post_latest_swap ->
+  post and queue more callbacks
+
+So later in shutdown those callbacks would trigger an assertion failure
+in meta_kms_impl_device_atomic_finalize:
+
+  g_hash_table_size (impl_device_atomic->page_flip_datas) == 0
+---
+ src/backends/native/meta-onscreen-native.c | 5 ++++-
+ 1 file changed, 4 insertions(+), 1 deletion(-)
+
+diff --git a/src/backends/native/meta-onscreen-native.c b/src/backends/native/meta-onscreen-native.c
+index 0c608237c..65e48f2ea 100644
+--- a/src/backends/native/meta-onscreen-native.c
++++ b/src/backends/native/meta-onscreen-native.c
+@@ -1510,6 +1510,8 @@ try_post_latest_swap (CoglOnscreen *onscreen)
+   MetaRendererNative *renderer_native = renderer_gpu_data->renderer_native;
+   MetaRenderer *renderer = META_RENDERER (renderer_native);
+   MetaBackend *backend = meta_renderer_get_backend (renderer);
++  MetaBackendNative *backend_native = META_BACKEND_NATIVE (backend);
++  MetaKms *kms = meta_backend_native_get_kms (backend_native);
+   MetaMonitorManager *monitor_manager =
+     meta_backend_get_monitor_manager (backend);
+   MetaOnscreenNative *onscreen_native = META_ONSCREEN_NATIVE (onscreen);
+@@ -1522,7 +1524,8 @@ try_post_latest_swap (CoglOnscreen *onscreen)
+   g_autoptr (ClutterFrame) frame = NULL;
+   MetaFrameNative *frame_native;
+ 
+-  if (onscreen_native->next_post.frame == NULL)
++  if (onscreen_native->next_post.frame == NULL ||
++      meta_kms_is_shutting_down (kms))
+     return;
+ 
+   power_save_mode = meta_monitor_manager_get_power_save_mode (monitor_manager);
+-- 
+2.45.0
+
+
+From 0daf4a48f8cec7cc672249b28652bf0267bda9ee Mon Sep 17 00:00:00 2001
+From: Daniel van Vugt <daniel.van.vugt@canonical.com>
+Date: Thu, 4 Nov 2021 16:09:52 +0800
+Subject: [PATCH 16/34] renderer/native: Discard pending swaps when rebuilding
+ views
+
+It's analogous to discard_pending_page_flips but represents swaps that
+might become flips after the next frame notification callbacks, thanks
+to triple buffering. Since the views are being rebuilt and their onscreens
+are about to be destroyed, turning those swaps into more flips/posts would
+just lead to unexpected behaviour (like trying to flip on a half-destroyed
+inactive CRTC).
+---
+ src/backends/native/meta-renderer-native.c | 21 +++++++++++++++++++++
+ 1 file changed, 21 insertions(+)
+
 diff --git a/src/backends/native/meta-renderer-native.c b/src/backends/native/meta-renderer-native.c
-index aa76d018ca29b56271d34d81bf39995e14093884..3c22b4e86a7cff8ed7bf378621c9ec63c6e79e5f 100644
+index 601fd674a..3c22b4e86 100644
 --- a/src/backends/native/meta-renderer-native.c
 +++ b/src/backends/native/meta-renderer-native.c
-@@ -731,12 +731,18 @@ static gboolean
- dummy_power_save_page_flip_cb (gpointer user_data)
- {
-   MetaRendererNative *renderer_native = user_data;
-+  GList *old_list =
-+    g_steal_pointer (&renderer_native->power_save_page_flip_onscreens);
- 
--  g_list_foreach (renderer_native->power_save_page_flip_onscreens,
-+  g_list_foreach (old_list,
-                   (GFunc) meta_onscreen_native_dummy_power_save_page_flip,
-                   NULL);
--  g_clear_list (&renderer_native->power_save_page_flip_onscreens,
-+  g_clear_list (&old_list,
-                 g_object_unref);
-+
-+  if (renderer_native->power_save_page_flip_onscreens != NULL)
-+    return G_SOURCE_CONTINUE;
-+
-   renderer_native->power_save_page_flip_source_id = 0;
- 
-   return G_SOURCE_REMOVE;
-@@ -748,6 +754,9 @@ meta_renderer_native_queue_power_save_page_flip (MetaRendererNative *renderer_na
- {
-   const unsigned int timeout_ms = 100;
- 
-+  if (g_list_find (renderer_native->power_save_page_flip_onscreens, onscreen))
-+    return;
-+
-   if (!renderer_native->power_save_page_flip_source_id)
-     {
-       renderer_native->power_save_page_flip_source_id =
-@@ -1529,6 +1538,26 @@ detach_onscreens (MetaRenderer *renderer)
+@@ -1538,6 +1538,26 @@ detach_onscreens (MetaRenderer *renderer)
      }
  }
  
@@ -1627,7 +1258,7 @@ index aa76d018ca29b56271d34d81bf39995e14093884..3c22b4e86a7cff8ed7bf378621c9ec63
  static void
  meta_renderer_native_rebuild_views (MetaRenderer *renderer)
  {
-@@ -1539,6 +1568,7 @@ meta_renderer_native_rebuild_views (MetaRenderer *renderer)
+@@ -1548,6 +1568,7 @@ meta_renderer_native_rebuild_views (MetaRenderer *renderer)
    MetaRendererClass *parent_renderer_class =
      META_RENDERER_CLASS (meta_renderer_native_parent_class);
  
@@ -1635,8 +1266,1075 @@ index aa76d018ca29b56271d34d81bf39995e14093884..3c22b4e86a7cff8ed7bf378621c9ec63
    meta_kms_discard_pending_page_flips (kms);
    g_hash_table_remove_all (renderer_native->mode_set_updates);
  
+-- 
+2.45.0
+
+
+From fab0d3d57ed2721b32dcc2e282b9f5f6cce3857d Mon Sep 17 00:00:00 2001
+From: Daniel van Vugt <daniel.van.vugt@canonical.com>
+Date: Thu, 7 Dec 2023 16:28:20 +0800
+Subject: [PATCH 17/34] clutter/frame-clock: Reuse existing idle period
+ detection
+
+While it was correct for double buffering, the test was wrong for
+triple buffering and would lead to accidentally staying in triple
+buffering for too long.
+
+Fixes: 8f27ebf87eee6057992a90560d4118ab7bdf138d
+---
+ clutter/clutter/clutter-frame-clock.c | 6 ++++--
+ 1 file changed, 4 insertions(+), 2 deletions(-)
+
+diff --git a/clutter/clutter/clutter-frame-clock.c b/clutter/clutter/clutter-frame-clock.c
+index 93e4c9329..1b212ee3f 100644
+--- a/clutter/clutter/clutter-frame-clock.c
++++ b/clutter/clutter/clutter-frame-clock.c
+@@ -491,6 +491,7 @@ calculate_next_update_time_us (ClutterFrameClock *frame_clock,
+   int64_t min_render_time_allowed_us;
+   int64_t max_render_time_allowed_us;
+   int64_t next_presentation_time_us;
++  int64_t next_smooth_presentation_time_us;
+   int64_t next_update_time_us;
+ 
+   now_us = g_get_monotonic_time ();
+@@ -535,7 +536,8 @@ calculate_next_update_time_us (ClutterFrameClock *frame_clock,
+    *
+    */
+   last_presentation_time_us = frame_clock->last_presentation_time_us;
+-  next_presentation_time_us = last_presentation_time_us + refresh_interval_us;
++  next_smooth_presentation_time_us = last_presentation_time_us + refresh_interval_us;
++  next_presentation_time_us = next_smooth_presentation_time_us;
+ 
+   /*
+    * However, the last presentation could have happened more than a frame ago.
+@@ -601,7 +603,7 @@ calculate_next_update_time_us (ClutterFrameClock *frame_clock,
+         }
+     }
+ 
+-  if (next_presentation_time_us != last_presentation_time_us + refresh_interval_us)
++  if (next_presentation_time_us != next_smooth_presentation_time_us)
+     {
+       /* There was an idle period since the last presentation, so there seems
+        * be no constantly updating actor. In this case it's best to start
+-- 
+2.45.0
+
+
+From e106557ea916ca8400f2059c7e5a257ce5d2ceac Mon Sep 17 00:00:00 2001
+From: Daniel van Vugt <daniel.van.vugt@canonical.com>
+Date: Tue, 10 Aug 2021 17:46:49 +0800
+Subject: [PATCH 18/34] clutter/frame-clock: Lower the threshold for disabling
+ error diffusion
+
+Error diffusion was introduced in 0555a5bbc15 for Nvidia where last
+presentation time is always unknown (zero). Dispatch times would drift
+apart always being a fraction of a frame late, and accumulated to cause
+periodic frame skips. So error diffusion corrected that precisely and
+avoided the skips.
+
+That works great with double buffering but less great with triple
+buffering. It's certainly still needed with triple buffering but
+correcting for a lateness of many milliseconds isn't a good idea. That's
+because a dispatch being that late is not due to main loop jitter but due
+to Nvidia's swap buffers blocking when the queue is full. So scheduling
+the next frame even earlier using last_dispatch_lateness_us would just
+perpetuate the problem of swap buffers blocking for too long.
+
+So now we lower the threshold of when error diffusion gets disabled. It's
+still high enough to fix the original smoothness problem it was for, but
+now low enough to detect Nvidia's occasionally blocking swaps and backs
+off in that case.
+
+Since the average duration of a blocking swap is half a frame interval
+and we want to distinguish between that and sub-millisecond jitter, the
+logical threshold is halfway again: refresh_interval_us/4.
+---
+ clutter/clutter/clutter-frame-clock.c | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/clutter/clutter/clutter-frame-clock.c b/clutter/clutter/clutter-frame-clock.c
+index 1b212ee3f..48f07e101 100644
+--- a/clutter/clutter/clutter-frame-clock.c
++++ b/clutter/clutter/clutter-frame-clock.c
+@@ -924,7 +924,7 @@ clutter_frame_clock_dispatch (ClutterFrameClock *frame_clock,
+                              frame_clock->refresh_interval_us;
+ 
+   lateness_us = time_us - ideal_dispatch_time_us;
+-  if (lateness_us < 0 || lateness_us >= frame_clock->refresh_interval_us)
++  if (lateness_us < 0 || lateness_us >= frame_clock->refresh_interval_us / 4)
+     frame_clock->last_dispatch_lateness_us = 0;
+   else
+     frame_clock->last_dispatch_lateness_us = lateness_us;
+-- 
+2.45.0
+
+
+From 776e619e0311eebd9ff87c5d303512b91df42b20 Mon Sep 17 00:00:00 2001
+From: Daniel van Vugt <daniel.van.vugt@canonical.com>
+Date: Fri, 24 Jul 2020 14:13:11 +0800
+Subject: [PATCH 19/34] clutter/frame-clock: Merge states DISPATCHING and
+ PENDING_PRESENTED
+
+Chronologically they already overlap in time as presentation may
+complete in the middle of the dispatch function, otherwise they are
+contiguous in time. And most switch statements treated the two states
+the same already so they're easy to merge into a single `DISPATCHED`
+state.
+
+Having fewer states now will make life easier when we add more states
+later.
+---
+ clutter/clutter/clutter-frame-clock.c | 31 ++++++++++-----------------
+ 1 file changed, 11 insertions(+), 20 deletions(-)
+
+diff --git a/clutter/clutter/clutter-frame-clock.c b/clutter/clutter/clutter-frame-clock.c
+index 48f07e101..384537e41 100644
+--- a/clutter/clutter/clutter-frame-clock.c
++++ b/clutter/clutter/clutter-frame-clock.c
+@@ -70,8 +70,7 @@ typedef enum _ClutterFrameClockState
+   CLUTTER_FRAME_CLOCK_STATE_IDLE,
+   CLUTTER_FRAME_CLOCK_STATE_SCHEDULED,
+   CLUTTER_FRAME_CLOCK_STATE_SCHEDULED_NOW,
+-  CLUTTER_FRAME_CLOCK_STATE_DISPATCHING,
+-  CLUTTER_FRAME_CLOCK_STATE_PENDING_PRESENTED,
++  CLUTTER_FRAME_CLOCK_STATE_DISPATCHED,
+ } ClutterFrameClockState;
+ 
+ struct _ClutterFrameClock
+@@ -413,8 +412,7 @@ clutter_frame_clock_notify_presented (ClutterFrameClock *frame_clock,
+     case CLUTTER_FRAME_CLOCK_STATE_SCHEDULED_NOW:
+       g_warn_if_reached ();
+       break;
+-    case CLUTTER_FRAME_CLOCK_STATE_DISPATCHING:
+-    case CLUTTER_FRAME_CLOCK_STATE_PENDING_PRESENTED:
++    case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED:
+       frame_clock->state = CLUTTER_FRAME_CLOCK_STATE_IDLE;
+       maybe_reschedule_update (frame_clock);
+       break;
+@@ -435,8 +433,7 @@ clutter_frame_clock_notify_ready (ClutterFrameClock *frame_clock)
+     case CLUTTER_FRAME_CLOCK_STATE_SCHEDULED_NOW:
+       g_warn_if_reached ();
+       break;
+-    case CLUTTER_FRAME_CLOCK_STATE_DISPATCHING:
+-    case CLUTTER_FRAME_CLOCK_STATE_PENDING_PRESENTED:
++    case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED:
+       frame_clock->state = CLUTTER_FRAME_CLOCK_STATE_IDLE;
+       maybe_reschedule_update (frame_clock);
+       break;
+@@ -735,8 +732,7 @@ clutter_frame_clock_inhibit (ClutterFrameClock *frame_clock)
+           frame_clock->pending_reschedule_now = TRUE;
+           frame_clock->state = CLUTTER_FRAME_CLOCK_STATE_IDLE;
+           break;
+-        case CLUTTER_FRAME_CLOCK_STATE_DISPATCHING:
+-        case CLUTTER_FRAME_CLOCK_STATE_PENDING_PRESENTED:
++        case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED:
+           break;
+         }
+ 
+@@ -775,8 +771,7 @@ clutter_frame_clock_schedule_update_now (ClutterFrameClock *frame_clock)
+       break;
+     case CLUTTER_FRAME_CLOCK_STATE_SCHEDULED_NOW:
+       return;
+-    case CLUTTER_FRAME_CLOCK_STATE_DISPATCHING:
+-    case CLUTTER_FRAME_CLOCK_STATE_PENDING_PRESENTED:
++    case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED:
+       frame_clock->pending_reschedule = TRUE;
+       frame_clock->pending_reschedule_now = TRUE;
+       return;
+@@ -831,8 +826,7 @@ clutter_frame_clock_schedule_update (ClutterFrameClock *frame_clock)
+     case CLUTTER_FRAME_CLOCK_STATE_SCHEDULED:
+     case CLUTTER_FRAME_CLOCK_STATE_SCHEDULED_NOW:
+       return;
+-    case CLUTTER_FRAME_CLOCK_STATE_DISPATCHING:
+-    case CLUTTER_FRAME_CLOCK_STATE_PENDING_PRESENTED:
++    case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED:
+       frame_clock->pending_reschedule = TRUE;
+       return;
+     }
+@@ -887,8 +881,7 @@ clutter_frame_clock_set_mode (ClutterFrameClock     *frame_clock,
+       frame_clock->pending_reschedule_now = TRUE;
+       frame_clock->state = CLUTTER_FRAME_CLOCK_STATE_IDLE;
+       break;
+-    case CLUTTER_FRAME_CLOCK_STATE_DISPATCHING:
+-    case CLUTTER_FRAME_CLOCK_STATE_PENDING_PRESENTED:
++    case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED:
+       break;
+     }
+ 
+@@ -948,7 +941,7 @@ clutter_frame_clock_dispatch (ClutterFrameClock *frame_clock,
+   frame_clock->last_dispatch_time_us = time_us;
+   g_source_set_ready_time (frame_clock->source, -1);
+ 
+-  frame_clock->state = CLUTTER_FRAME_CLOCK_STATE_DISPATCHING;
++  frame_clock->state = CLUTTER_FRAME_CLOCK_STATE_DISPATCHED;
+ 
+   frame_count = frame_clock->frame_count++;
+ 
+@@ -982,20 +975,20 @@ clutter_frame_clock_dispatch (ClutterFrameClock *frame_clock,
+   switch (frame_clock->state)
+     {
+     case CLUTTER_FRAME_CLOCK_STATE_INIT:
+-    case CLUTTER_FRAME_CLOCK_STATE_PENDING_PRESENTED:
+       g_warn_if_reached ();
+       break;
+     case CLUTTER_FRAME_CLOCK_STATE_IDLE:
++      /* Presentation completed synchronously in the above listener */
+     case CLUTTER_FRAME_CLOCK_STATE_SCHEDULED:
+     case CLUTTER_FRAME_CLOCK_STATE_SCHEDULED_NOW:
+       break;
+-    case CLUTTER_FRAME_CLOCK_STATE_DISPATCHING:
++    case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED:
+       switch (result)
+         {
+         case CLUTTER_FRAME_RESULT_PENDING_PRESENTED:
+-          frame_clock->state = CLUTTER_FRAME_CLOCK_STATE_PENDING_PRESENTED;
+           break;
+         case CLUTTER_FRAME_RESULT_IDLE:
++          /* The frame was aborted; nothing to paint/present */
+           frame_clock->state = CLUTTER_FRAME_CLOCK_STATE_IDLE;
+           maybe_reschedule_update (frame_clock);
+           break;
+@@ -1212,8 +1205,6 @@ clutter_frame_clock_dispose (GObject *object)
+ {
+   ClutterFrameClock *frame_clock = CLUTTER_FRAME_CLOCK (object);
+ 
+-  g_warn_if_fail (frame_clock->state != CLUTTER_FRAME_CLOCK_STATE_DISPATCHING);
+-
+   if (frame_clock->source)
+     {
+       g_signal_emit (frame_clock, signals[DESTROY], 0);
+-- 
+2.45.0
+
+
+From f28ce8aa1cc9d5dba8611cefb570f4ca1dec43d6 Mon Sep 17 00:00:00 2001
+From: Daniel van Vugt <daniel.van.vugt@canonical.com>
+Date: Mon, 13 Dec 2021 17:03:44 +0800
+Subject: [PATCH 20/34] clutter/frame-clock: Clamp render times to two frames,
+ not one
+
+Because the buffer queue may grow by an extra frame in triple buffering,
+we need measurements exceeding one frame to indicate when and by how much
+the scaling is necessary.
+---
+ clutter/clutter/clutter-frame-clock.c | 4 ++--
+ 1 file changed, 2 insertions(+), 2 deletions(-)
+
+diff --git a/clutter/clutter/clutter-frame-clock.c b/clutter/clutter/clutter-frame-clock.c
+index 384537e41..6a11d4b66 100644
+--- a/clutter/clutter/clutter-frame-clock.c
++++ b/clutter/clutter/clutter-frame-clock.c
+@@ -385,7 +385,7 @@ clutter_frame_clock_notify_presented (ClutterFrameClock *frame_clock,
+         CLAMP (frame_clock->last_dispatch_lateness_us + dispatch_to_swap_us +
+                MAX (swap_to_rendering_done_us, swap_to_flip_us),
+                frame_clock->shortterm_max_update_duration_us,
+-               frame_clock->refresh_interval_us);
++               2 * frame_clock->refresh_interval_us);
+ 
+       maybe_update_longterm_max_duration_us (frame_clock, frame_info);
+ 
+@@ -471,7 +471,7 @@ clutter_frame_clock_compute_max_render_time_us (ClutterFrameClock *frame_clock)
+     frame_clock->vblank_duration_us +
+     clutter_max_render_time_constant_us;
+ 
+-  max_render_time_us = CLAMP (max_render_time_us, 0, refresh_interval_us);
++  max_render_time_us = CLAMP (max_render_time_us, 0, 2 * refresh_interval_us);
+ 
+   return max_render_time_us;
+ }
+-- 
+2.45.0
+
+
+From cfaee218edf230a29d443773ff40c94d45ee2dea Mon Sep 17 00:00:00 2001
+From: Daniel van Vugt <daniel.van.vugt@canonical.com>
+Date: Thu, 10 Sep 2020 16:34:53 +0800
+Subject: [PATCH 21/34] clutter/frame-clock: Add triple buffering support
+
+---
+ clutter/clutter/clutter-frame-clock.c | 198 ++++++++++++++++++++++----
+ 1 file changed, 170 insertions(+), 28 deletions(-)
+
+diff --git a/clutter/clutter/clutter-frame-clock.c b/clutter/clutter/clutter-frame-clock.c
+index 6a11d4b66..32d2b2d87 100644
+--- a/clutter/clutter/clutter-frame-clock.c
++++ b/clutter/clutter/clutter-frame-clock.c
+@@ -70,7 +70,10 @@ typedef enum _ClutterFrameClockState
+   CLUTTER_FRAME_CLOCK_STATE_IDLE,
+   CLUTTER_FRAME_CLOCK_STATE_SCHEDULED,
+   CLUTTER_FRAME_CLOCK_STATE_SCHEDULED_NOW,
+-  CLUTTER_FRAME_CLOCK_STATE_DISPATCHED,
++  CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE,
++  CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE_AND_SCHEDULED,
++  CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE_AND_SCHEDULED_NOW,
++  CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_TWO,
+ } ClutterFrameClockState;
+ 
+ struct _ClutterFrameClock
+@@ -91,6 +94,7 @@ struct _ClutterFrameClock
+   ClutterFrameClockMode mode;
+ 
+   int64_t last_dispatch_time_us;
++  int64_t prev_last_dispatch_time_us;
+   int64_t last_dispatch_lateness_us;
+   int64_t last_presentation_time_us;
+   int64_t next_update_time_us;
+@@ -110,6 +114,7 @@ struct _ClutterFrameClock
+   int64_t vblank_duration_us;
+   /* Last KMS buffer submission time. */
+   int64_t last_flip_time_us;
++  int64_t prev_last_flip_time_us;
+ 
+   /* Last time we promoted short-term maximum to long-term one */
+   int64_t longterm_promotion_us;
+@@ -364,14 +369,35 @@ clutter_frame_clock_notify_presented (ClutterFrameClock *frame_clock,
+       frame_info->has_valid_gpu_rendering_duration)
+     {
+       int64_t dispatch_to_swap_us, swap_to_rendering_done_us, swap_to_flip_us;
++      int64_t dispatch_time_us = 0, flip_time_us = 0;
++
++      switch (frame_clock->state)
++        {
++        case CLUTTER_FRAME_CLOCK_STATE_INIT:
++        case CLUTTER_FRAME_CLOCK_STATE_IDLE:
++        case CLUTTER_FRAME_CLOCK_STATE_SCHEDULED:
++        case CLUTTER_FRAME_CLOCK_STATE_SCHEDULED_NOW:
++          g_warn_if_reached ();
++          G_GNUC_FALLTHROUGH;
++        case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE:
++        case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE_AND_SCHEDULED:
++        case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE_AND_SCHEDULED_NOW:
++          dispatch_time_us = frame_clock->last_dispatch_time_us;
++          flip_time_us = frame_clock->last_flip_time_us;
++          break;
++        case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_TWO:
++          dispatch_time_us = frame_clock->prev_last_dispatch_time_us;
++          flip_time_us = frame_clock->prev_last_flip_time_us;
++          break;
++        }
+ 
+       dispatch_to_swap_us =
+         frame_info->cpu_time_before_buffer_swap_us -
+-        frame_clock->last_dispatch_time_us;
++        dispatch_time_us;
+       swap_to_rendering_done_us =
+         frame_info->gpu_rendering_duration_ns / 1000;
+       swap_to_flip_us =
+-        frame_clock->last_flip_time_us -
++        flip_time_us -
+         frame_info->cpu_time_before_buffer_swap_us;
+ 
+       CLUTTER_NOTE (FRAME_TIMINGS,
+@@ -412,10 +438,22 @@ clutter_frame_clock_notify_presented (ClutterFrameClock *frame_clock,
+     case CLUTTER_FRAME_CLOCK_STATE_SCHEDULED_NOW:
+       g_warn_if_reached ();
+       break;
+-    case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED:
++    case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE:
+       frame_clock->state = CLUTTER_FRAME_CLOCK_STATE_IDLE;
+       maybe_reschedule_update (frame_clock);
+       break;
++    case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE_AND_SCHEDULED:
++      frame_clock->state = CLUTTER_FRAME_CLOCK_STATE_SCHEDULED;
++      maybe_reschedule_update (frame_clock);
++      break;
++    case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE_AND_SCHEDULED_NOW:
++      frame_clock->state = CLUTTER_FRAME_CLOCK_STATE_SCHEDULED_NOW;
++      maybe_reschedule_update (frame_clock);
++      break;
++    case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_TWO:
++      frame_clock->state = CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE;
++      maybe_reschedule_update (frame_clock);
++      break;
+     }
+ }
+ 
+@@ -433,10 +471,22 @@ clutter_frame_clock_notify_ready (ClutterFrameClock *frame_clock)
+     case CLUTTER_FRAME_CLOCK_STATE_SCHEDULED_NOW:
+       g_warn_if_reached ();
+       break;
+-    case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED:
++    case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE:
+       frame_clock->state = CLUTTER_FRAME_CLOCK_STATE_IDLE;
+       maybe_reschedule_update (frame_clock);
+       break;
++    case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE_AND_SCHEDULED:
++      frame_clock->state = CLUTTER_FRAME_CLOCK_STATE_SCHEDULED;
++      maybe_reschedule_update (frame_clock);
++      break;
++    case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE_AND_SCHEDULED_NOW:
++      frame_clock->state = CLUTTER_FRAME_CLOCK_STATE_SCHEDULED_NOW;
++      maybe_reschedule_update (frame_clock);
++      break;
++    case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_TWO:
++      frame_clock->state = CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE;
++      maybe_reschedule_update (frame_clock);
++      break;
+     }
+ }
+ 
+@@ -451,7 +501,14 @@ clutter_frame_clock_compute_max_render_time_us (ClutterFrameClock *frame_clock)
+   if (!frame_clock->ever_got_measurements ||
+       G_UNLIKELY (clutter_paint_debug_flags &
+                   CLUTTER_DEBUG_DISABLE_DYNAMIC_MAX_RENDER_TIME))
+-    return refresh_interval_us * SYNC_DELAY_FALLBACK_FRACTION;
++    {
++      int64_t ret = refresh_interval_us * SYNC_DELAY_FALLBACK_FRACTION;
++
++      if (frame_clock->state == CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE)
++        ret += refresh_interval_us;
++
++      return ret;
++    }
+ 
+   /* Max render time shows how early the frame clock needs to be dispatched
+    * to make it to the predicted next presentation time. It is an estimate of
+@@ -488,7 +545,7 @@ calculate_next_update_time_us (ClutterFrameClock *frame_clock,
+   int64_t min_render_time_allowed_us;
+   int64_t max_render_time_allowed_us;
+   int64_t next_presentation_time_us;
+-  int64_t next_smooth_presentation_time_us;
++  int64_t next_smooth_presentation_time_us = 0;
+   int64_t next_update_time_us;
+ 
+   now_us = g_get_monotonic_time ();
+@@ -533,7 +590,27 @@ calculate_next_update_time_us (ClutterFrameClock *frame_clock,
+    *
+    */
+   last_presentation_time_us = frame_clock->last_presentation_time_us;
+-  next_smooth_presentation_time_us = last_presentation_time_us + refresh_interval_us;
++  switch (frame_clock->state)
++    {
++    case CLUTTER_FRAME_CLOCK_STATE_INIT:
++    case CLUTTER_FRAME_CLOCK_STATE_IDLE:
++    case CLUTTER_FRAME_CLOCK_STATE_SCHEDULED:
++    case CLUTTER_FRAME_CLOCK_STATE_SCHEDULED_NOW:
++      next_smooth_presentation_time_us = last_presentation_time_us +
++                                         refresh_interval_us;
++      break;
++    case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE:
++    case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE_AND_SCHEDULED:
++    case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE_AND_SCHEDULED_NOW:
++      next_smooth_presentation_time_us = last_presentation_time_us +
++                                         2 * refresh_interval_us;
++      break;
++    case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_TWO:
++      next_smooth_presentation_time_us = last_presentation_time_us +
++                                         3 * refresh_interval_us;
++      break;
++    }
++
+   next_presentation_time_us = next_smooth_presentation_time_us;
+ 
+   /*
+@@ -732,7 +809,17 @@ clutter_frame_clock_inhibit (ClutterFrameClock *frame_clock)
+           frame_clock->pending_reschedule_now = TRUE;
+           frame_clock->state = CLUTTER_FRAME_CLOCK_STATE_IDLE;
+           break;
+-        case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED:
++        case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE_AND_SCHEDULED:
++          frame_clock->pending_reschedule = TRUE;
++          frame_clock->state = CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE;
++          break;
++        case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE_AND_SCHEDULED_NOW:
++          frame_clock->pending_reschedule = TRUE;
++          frame_clock->pending_reschedule_now = TRUE;
++          frame_clock->state = CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE;
++          break;
++        case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE:
++        case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_TWO:
+           break;
+         }
+ 
+@@ -768,10 +855,18 @@ clutter_frame_clock_schedule_update_now (ClutterFrameClock *frame_clock)
+     case CLUTTER_FRAME_CLOCK_STATE_INIT:
+     case CLUTTER_FRAME_CLOCK_STATE_IDLE:
+     case CLUTTER_FRAME_CLOCK_STATE_SCHEDULED:
++      frame_clock->state = CLUTTER_FRAME_CLOCK_STATE_SCHEDULED_NOW;
+       break;
+     case CLUTTER_FRAME_CLOCK_STATE_SCHEDULED_NOW:
++    case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE_AND_SCHEDULED_NOW:
+       return;
+-    case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED:
++    case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE:
++    case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE_AND_SCHEDULED:
++      next_update_time_us = g_get_monotonic_time ();
++      frame_clock->state =
++        CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE_AND_SCHEDULED_NOW;
++      break;
++    case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_TWO:
+       frame_clock->pending_reschedule = TRUE;
+       frame_clock->pending_reschedule_now = TRUE;
+       return;
+@@ -800,7 +895,6 @@ clutter_frame_clock_schedule_update_now (ClutterFrameClock *frame_clock)
+ 
+   frame_clock->next_update_time_us = next_update_time_us;
+   g_source_set_ready_time (frame_clock->source, next_update_time_us);
+-  frame_clock->state = CLUTTER_FRAME_CLOCK_STATE_SCHEDULED_NOW;
+ }
+ 
+ void
+@@ -822,11 +916,23 @@ clutter_frame_clock_schedule_update (ClutterFrameClock *frame_clock)
+       frame_clock->state = CLUTTER_FRAME_CLOCK_STATE_SCHEDULED;
+       return;
+     case CLUTTER_FRAME_CLOCK_STATE_IDLE:
++      frame_clock->state = CLUTTER_FRAME_CLOCK_STATE_SCHEDULED;
+       break;
+     case CLUTTER_FRAME_CLOCK_STATE_SCHEDULED:
+     case CLUTTER_FRAME_CLOCK_STATE_SCHEDULED_NOW:
++    case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE_AND_SCHEDULED:
++    case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE_AND_SCHEDULED_NOW:
+       return;
+-    case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED:
++    case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE:
++      calculate_next_update_time_us (frame_clock,
++                                     &next_update_time_us,
++                                     &frame_clock->next_presentation_time_us,
++                                     &frame_clock->next_frame_deadline_us);
++      frame_clock->is_next_presentation_time_valid =
++        (frame_clock->next_presentation_time_us != 0);
++      frame_clock->state = CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE_AND_SCHEDULED;
++      break;
++    case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_TWO:
+       frame_clock->pending_reschedule = TRUE;
+       return;
+     }
+@@ -855,7 +961,6 @@ clutter_frame_clock_schedule_update (ClutterFrameClock *frame_clock)
+ 
+   frame_clock->next_update_time_us = next_update_time_us;
+   g_source_set_ready_time (frame_clock->source, next_update_time_us);
+-  frame_clock->state = CLUTTER_FRAME_CLOCK_STATE_SCHEDULED;
+ }
+ 
+ void
+@@ -871,6 +976,8 @@ clutter_frame_clock_set_mode (ClutterFrameClock     *frame_clock,
+     {
+     case CLUTTER_FRAME_CLOCK_STATE_INIT:
+     case CLUTTER_FRAME_CLOCK_STATE_IDLE:
++    case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE:
++    case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_TWO:
+       break;
+     case CLUTTER_FRAME_CLOCK_STATE_SCHEDULED:
+       frame_clock->pending_reschedule = TRUE;
+@@ -881,7 +988,14 @@ clutter_frame_clock_set_mode (ClutterFrameClock     *frame_clock,
+       frame_clock->pending_reschedule_now = TRUE;
+       frame_clock->state = CLUTTER_FRAME_CLOCK_STATE_IDLE;
+       break;
+-    case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED:
++    case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE_AND_SCHEDULED:
++      frame_clock->pending_reschedule = TRUE;
++      frame_clock->state = CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE;
++      break;
++    case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE_AND_SCHEDULED_NOW:
++      frame_clock->pending_reschedule = TRUE;
++      frame_clock->pending_reschedule_now = TRUE;
++      frame_clock->state = CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE;
+       break;
+     }
+ 
+@@ -938,10 +1052,27 @@ clutter_frame_clock_dispatch (ClutterFrameClock *frame_clock,
+     }
+ #endif
+ 
++  frame_clock->prev_last_dispatch_time_us = frame_clock->last_dispatch_time_us;
+   frame_clock->last_dispatch_time_us = time_us;
+   g_source_set_ready_time (frame_clock->source, -1);
+ 
+-  frame_clock->state = CLUTTER_FRAME_CLOCK_STATE_DISPATCHED;
++  switch (frame_clock->state)
++    {
++    case CLUTTER_FRAME_CLOCK_STATE_INIT:
++    case CLUTTER_FRAME_CLOCK_STATE_IDLE:
++    case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE:
++    case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_TWO:
++      g_warn_if_reached ();
++      return;
++    case CLUTTER_FRAME_CLOCK_STATE_SCHEDULED:
++    case CLUTTER_FRAME_CLOCK_STATE_SCHEDULED_NOW:
++      frame_clock->state = CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE;
++      break;
++    case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE_AND_SCHEDULED:
++    case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE_AND_SCHEDULED_NOW:
++      frame_clock->state = CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_TWO;
++      break;
++    }
+ 
+   frame_count = frame_clock->frame_count++;
+ 
+@@ -972,26 +1103,36 @@ clutter_frame_clock_dispatch (ClutterFrameClock *frame_clock,
+   result = iface->frame (frame_clock, frame, frame_clock->listener.user_data);
+   COGL_TRACE_END (ClutterFrameClockFrame);
+ 
+-  switch (frame_clock->state)
++  switch (result)
+     {
+-    case CLUTTER_FRAME_CLOCK_STATE_INIT:
+-      g_warn_if_reached ();
++    case CLUTTER_FRAME_RESULT_PENDING_PRESENTED:
+       break;
+-    case CLUTTER_FRAME_CLOCK_STATE_IDLE:
+-      /* Presentation completed synchronously in the above listener */
+-    case CLUTTER_FRAME_CLOCK_STATE_SCHEDULED:
+-    case CLUTTER_FRAME_CLOCK_STATE_SCHEDULED_NOW:
+-      break;
+-    case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED:
+-      switch (result)
++    case CLUTTER_FRAME_RESULT_IDLE:
++      /* The frame was aborted; nothing to paint/present */
++      switch (frame_clock->state)
+         {
+-        case CLUTTER_FRAME_RESULT_PENDING_PRESENTED:
++        case CLUTTER_FRAME_CLOCK_STATE_INIT:
++        case CLUTTER_FRAME_CLOCK_STATE_IDLE:
++        case CLUTTER_FRAME_CLOCK_STATE_SCHEDULED:
++        case CLUTTER_FRAME_CLOCK_STATE_SCHEDULED_NOW:
++          g_warn_if_reached ();
+           break;
+-        case CLUTTER_FRAME_RESULT_IDLE:
+-          /* The frame was aborted; nothing to paint/present */
++        case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE:
+           frame_clock->state = CLUTTER_FRAME_CLOCK_STATE_IDLE;
+           maybe_reschedule_update (frame_clock);
+           break;
++        case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE_AND_SCHEDULED:
++          frame_clock->state = CLUTTER_FRAME_CLOCK_STATE_SCHEDULED;
++          maybe_reschedule_update (frame_clock);
++          break;
++        case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE_AND_SCHEDULED_NOW:
++          frame_clock->state = CLUTTER_FRAME_CLOCK_STATE_SCHEDULED_NOW;
++          maybe_reschedule_update (frame_clock);
++          break;
++        case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_TWO:
++          frame_clock->state = CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE;
++          maybe_reschedule_update (frame_clock);
++          break;
+         }
+       break;
+     }
+@@ -1027,6 +1168,7 @@ void
+ clutter_frame_clock_record_flip_time (ClutterFrameClock *frame_clock,
+                                       int64_t            flip_time_us)
+ {
++  frame_clock->prev_last_flip_time_us = frame_clock->last_flip_time_us;
+   frame_clock->last_flip_time_us = flip_time_us;
+ }
+ 
+-- 
+2.45.0
+
+
+From 92b566e4d992c32ff344d5cbfde55a3f2fe721e1 Mon Sep 17 00:00:00 2001
+From: Daniel van Vugt <daniel.van.vugt@canonical.com>
+Date: Fri, 10 Dec 2021 16:28:04 +0800
+Subject: [PATCH 22/34] clutter/frame-clock: Log N-buffers in
+ CLUTTTER_DEBUG=frame-timings
+
+---
+ clutter/clutter/clutter-frame-clock.c | 12 ++++++++++--
+ 1 file changed, 10 insertions(+), 2 deletions(-)
+
+diff --git a/clutter/clutter/clutter-frame-clock.c b/clutter/clutter/clutter-frame-clock.c
+index 32d2b2d87..e3fb23086 100644
+--- a/clutter/clutter/clutter-frame-clock.c
++++ b/clutter/clutter/clutter-frame-clock.c
+@@ -279,6 +279,12 @@ void
+ clutter_frame_clock_notify_presented (ClutterFrameClock *frame_clock,
+                                       ClutterFrameInfo  *frame_info)
+ {
++#ifdef CLUTTER_ENABLE_DEBUG
++  const char *debug_state =
++    frame_clock->state == CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_TWO ?
++    "Triple buffering" : "Double buffering";
++#endif
++
+   COGL_TRACE_BEGIN_SCOPED (ClutterFrameClockNotifyPresented,
+                            "Clutter::FrameClock::presented()");
+   COGL_TRACE_DESCRIBE (ClutterFrameClockNotifyPresented,
+@@ -401,7 +407,8 @@ clutter_frame_clock_notify_presented (ClutterFrameClock *frame_clock,
+         frame_info->cpu_time_before_buffer_swap_us;
+ 
+       CLUTTER_NOTE (FRAME_TIMINGS,
+-                    "update2dispatch %ld µs, dispatch2swap %ld µs, swap2render %ld µs, swap2flip %ld µs",
++                    "%s: update2dispatch %ld µs, dispatch2swap %ld µs, swap2render %ld µs, swap2flip %ld µs",
++                    debug_state,
+                     frame_clock->last_dispatch_lateness_us,
+                     dispatch_to_swap_us,
+                     swap_to_rendering_done_us,
+@@ -420,7 +427,8 @@ clutter_frame_clock_notify_presented (ClutterFrameClock *frame_clock,
+     }
+   else
+     {
+-      CLUTTER_NOTE (FRAME_TIMINGS, "update2dispatch %ld µs",
++      CLUTTER_NOTE (FRAME_TIMINGS, "%s: update2dispatch %ld µs",
++                    debug_state,
+                     frame_clock->last_dispatch_lateness_us);
+     }
+ 
+-- 
+2.45.0
+
+
+From 9209eba42a0f37c0d178362152d93b2729f93ed4 Mon Sep 17 00:00:00 2001
+From: Daniel van Vugt <daniel.van.vugt@canonical.com>
+Date: Tue, 7 Sep 2021 19:08:15 +0800
+Subject: [PATCH 23/34] clutter/frame: Add ClutterFrameHint to ClutterFrame
+
+This will allow the backend to provide performance hints to the frame
+clock in future.
+---
+ clutter/clutter/clutter-frame-clock.h   |  6 ++++++
+ clutter/clutter/clutter-frame-private.h |  1 +
+ clutter/clutter/clutter-frame.c         | 13 +++++++++++++
+ clutter/clutter/clutter-frame.h         |  7 +++++++
+ 4 files changed, 27 insertions(+)
+
+diff --git a/clutter/clutter/clutter-frame-clock.h b/clutter/clutter/clutter-frame-clock.h
+index a7be5ef31..5adf99509 100644
+--- a/clutter/clutter/clutter-frame-clock.h
++++ b/clutter/clutter/clutter-frame-clock.h
+@@ -33,6 +33,12 @@ typedef enum _ClutterFrameResult
+   CLUTTER_FRAME_RESULT_IDLE,
+ } ClutterFrameResult;
+ 
++typedef enum _ClutterFrameHint
++{
++  CLUTTER_FRAME_HINT_NONE                     = 0,
++  CLUTTER_FRAME_HINT_DIRECT_SCANOUT_ATTEMPTED = 1 << 0,
++} ClutterFrameHint;
++
+ #define CLUTTER_TYPE_FRAME_CLOCK (clutter_frame_clock_get_type ())
+ CLUTTER_EXPORT
+ G_DECLARE_FINAL_TYPE (ClutterFrameClock, clutter_frame_clock,
+diff --git a/clutter/clutter/clutter-frame-private.h b/clutter/clutter/clutter-frame-private.h
+index ef66b874e..ce140560a 100644
+--- a/clutter/clutter/clutter-frame-private.h
++++ b/clutter/clutter/clutter-frame-private.h
+@@ -36,6 +36,7 @@ struct _ClutterFrame
+ 
+   gboolean has_result;
+   ClutterFrameResult result;
++  ClutterFrameHint hints;
+ };
+ 
+ CLUTTER_EXPORT
+diff --git a/clutter/clutter/clutter-frame.c b/clutter/clutter/clutter-frame.c
+index 7436f9f18..53c289b2c 100644
+--- a/clutter/clutter/clutter-frame.c
++++ b/clutter/clutter/clutter-frame.c
+@@ -115,3 +115,16 @@ clutter_frame_set_result (ClutterFrame       *frame,
+   frame->result = result;
+   frame->has_result = TRUE;
+ }
++
++void
++clutter_frame_set_hint (ClutterFrame     *frame,
++                        ClutterFrameHint  hint)
++{
++  frame->hints |= hint;
++}
++
++ClutterFrameHint
++clutter_frame_get_hints (ClutterFrame *frame)
++{
++  return frame->hints;
++}
+diff --git a/clutter/clutter/clutter-frame.h b/clutter/clutter/clutter-frame.h
+index 34f0770bd..c7b3d02ac 100644
+--- a/clutter/clutter/clutter-frame.h
++++ b/clutter/clutter/clutter-frame.h
+@@ -54,4 +54,11 @@ void clutter_frame_set_result (ClutterFrame       *frame,
+ CLUTTER_EXPORT
+ gboolean clutter_frame_has_result (ClutterFrame *frame);
+ 
++CLUTTER_EXPORT
++void clutter_frame_set_hint (ClutterFrame     *frame,
++                             ClutterFrameHint  hint);
++
++CLUTTER_EXPORT
++ClutterFrameHint clutter_frame_get_hints (ClutterFrame *frame);
++
+ G_DEFINE_AUTOPTR_CLEANUP_FUNC (ClutterFrame, clutter_frame_unref)
+-- 
+2.45.0
+
+
+From fb3a7d3fba001d2154b38bac0abe660458e50b0d Mon Sep 17 00:00:00 2001
+From: Daniel van Vugt <daniel.van.vugt@canonical.com>
+Date: Tue, 7 Sep 2021 19:10:26 +0800
+Subject: [PATCH 24/34] backends: Flag that the frame attempted direct scanout
+
+We need this hint whether direct scanout succeeds or fails because it's
+the mechanism by which we will tell the clock to enforce double buffering,
+thus making direct scanout possible on future frames. Triple buffering
+will be disabled until such time that direct scanout is not being attempted.
+---
+ src/backends/meta-stage-impl.c | 2 ++
+ 1 file changed, 2 insertions(+)
+
+diff --git a/src/backends/meta-stage-impl.c b/src/backends/meta-stage-impl.c
+index 7aa24439d..727e1a5f3 100644
+--- a/src/backends/meta-stage-impl.c
++++ b/src/backends/meta-stage-impl.c
+@@ -774,6 +774,8 @@ meta_stage_impl_redraw_view (ClutterStageWindow *stage_window,
+     {
+       g_autoptr (GError) error = NULL;
+ 
++      clutter_frame_set_hint (frame, CLUTTER_FRAME_HINT_DIRECT_SCANOUT_ATTEMPTED);
++
+       if (meta_stage_impl_scanout_view (stage_impl,
+                                         stage_view,
+                                         scanout,
+-- 
+2.45.0
+
+
+From 70d35955aca38a14aafef8bbe9eefde93e508eec Mon Sep 17 00:00:00 2001
+From: Daniel van Vugt <daniel.van.vugt@canonical.com>
+Date: Tue, 7 Sep 2021 19:15:18 +0800
+Subject: [PATCH 25/34] clutter: Pass ClutterFrameHint(s) to the frame clock
+
+---
+ clutter/clutter/clutter-frame-clock.c |  8 ++++++--
+ clutter/clutter/clutter-frame-clock.h |  5 +++--
+ clutter/clutter/clutter-stage-view.c  | 11 +++++++++--
+ 3 files changed, 18 insertions(+), 6 deletions(-)
+
+diff --git a/clutter/clutter/clutter-frame-clock.c b/clutter/clutter/clutter-frame-clock.c
+index e3fb23086..84d2f1f31 100644
+--- a/clutter/clutter/clutter-frame-clock.c
++++ b/clutter/clutter/clutter-frame-clock.c
+@@ -116,6 +116,8 @@ struct _ClutterFrameClock
+   int64_t last_flip_time_us;
+   int64_t prev_last_flip_time_us;
+ 
++  ClutterFrameHint last_flip_hints;
++
+   /* Last time we promoted short-term maximum to long-term one */
+   int64_t longterm_promotion_us;
+   /* Long-term maximum update duration */
+@@ -1173,11 +1175,13 @@ frame_clock_source_dispatch (GSource     *source,
+ }
+ 
+ void
+-clutter_frame_clock_record_flip_time (ClutterFrameClock *frame_clock,
+-                                      int64_t            flip_time_us)
++clutter_frame_clock_record_flip (ClutterFrameClock *frame_clock,
++                                 int64_t            flip_time_us,
++                                 ClutterFrameHint   hints)
+ {
+   frame_clock->prev_last_flip_time_us = frame_clock->last_flip_time_us;
+   frame_clock->last_flip_time_us = flip_time_us;
++  frame_clock->last_flip_hints = hints;
+ }
+ 
+ GString *
+diff --git a/clutter/clutter/clutter-frame-clock.h b/clutter/clutter/clutter-frame-clock.h
+index 5adf99509..bfc89bde0 100644
+--- a/clutter/clutter/clutter-frame-clock.h
++++ b/clutter/clutter/clutter-frame-clock.h
+@@ -108,7 +108,8 @@ void clutter_frame_clock_remove_timeline (ClutterFrameClock *frame_clock,
+ CLUTTER_EXPORT
+ float clutter_frame_clock_get_refresh_rate (ClutterFrameClock *frame_clock);
+ 
+-void clutter_frame_clock_record_flip_time (ClutterFrameClock *frame_clock,
+-                                           int64_t            flip_time_us);
++void clutter_frame_clock_record_flip (ClutterFrameClock *frame_clock,
++                                      int64_t            flip_time_us,
++                                      ClutterFrameHint   hints);
+ 
+ GString * clutter_frame_clock_get_max_render_time_debug_info (ClutterFrameClock *frame_clock);
+diff --git a/clutter/clutter/clutter-stage-view.c b/clutter/clutter/clutter-stage-view.c
+index f5188e2ac..d53e37785 100644
+--- a/clutter/clutter/clutter-stage-view.c
++++ b/clutter/clutter/clutter-stage-view.c
+@@ -898,14 +898,21 @@ handle_frame_clock_frame (ClutterFrameClock *frame_clock,
+ 
+       _clutter_stage_window_redraw_view (stage_window, view, frame);
+ 
+-      clutter_frame_clock_record_flip_time (frame_clock,
+-                                            g_get_monotonic_time ());
++      clutter_frame_clock_record_flip (frame_clock,
++                                       g_get_monotonic_time (),
++                                       clutter_frame_get_hints (frame));
+ 
+       clutter_stage_emit_after_paint (stage, view, frame);
+ 
+       if (_clutter_context_get_show_fps ())
+         end_frame_timing_measurement (view);
+     }
++  else
++    {
++      clutter_frame_clock_record_flip (frame_clock,
++                                       g_get_monotonic_time (),
++                                       clutter_frame_get_hints (frame));
++    }
+ 
+   _clutter_stage_window_finish_frame (stage_window, view, frame);
+ 
+-- 
+2.45.0
+
+
+From b1046b6b838bc4cb6ff089e5817455d763a874f1 Mon Sep 17 00:00:00 2001
+From: Daniel van Vugt <daniel.van.vugt@canonical.com>
+Date: Tue, 7 Sep 2021 19:15:55 +0800
+Subject: [PATCH 26/34] clutter/frame-clock: Throttle back to double buffering
+ for direct scanout
+
+There's no compositing during direct scanout so the "render" time is zero.
+Thus there is no need to implement triple buffering for direct scanouts.
+Stick to double buffering and enjoy the lower latency.
+---
+ clutter/clutter/clutter-frame-clock.c | 7 +++++++
+ 1 file changed, 7 insertions(+)
+
+diff --git a/clutter/clutter/clutter-frame-clock.c b/clutter/clutter/clutter-frame-clock.c
+index 84d2f1f31..c02eb85e2 100644
+--- a/clutter/clutter/clutter-frame-clock.c
++++ b/clutter/clutter/clutter-frame-clock.c
+@@ -934,6 +934,13 @@ clutter_frame_clock_schedule_update (ClutterFrameClock *frame_clock)
+     case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE_AND_SCHEDULED_NOW:
+       return;
+     case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE:
++      if (frame_clock->last_flip_hints & CLUTTER_FRAME_HINT_DIRECT_SCANOUT_ATTEMPTED)
++        {
++          /* Force double buffering, disable triple buffering */
++          frame_clock->pending_reschedule = TRUE;
++          return;
++        }
++
+       calculate_next_update_time_us (frame_clock,
+                                      &next_update_time_us,
+                                      &frame_clock->next_presentation_time_us,
+-- 
+2.45.0
+
+
+From 2a3bb7638d72bd262a70b3833ee82319646f14f1 Mon Sep 17 00:00:00 2001
+From: Daniel van Vugt <daniel.van.vugt@canonical.com>
+Date: Thu, 10 Mar 2022 16:44:14 +0800
+Subject: [PATCH 27/34] clutter/frame-clock: Add environment variable
+ MUTTER_DEBUG_TRIPLE_BUFFERING
+
+With possible values {never, auto, always} where auto is the default.
+
+This also allows some unification with automatic throttling for
+direct scanout.
+---
+ clutter/clutter/clutter-frame-clock.c | 55 ++++++++++++++++++++++-----
+ 1 file changed, 45 insertions(+), 10 deletions(-)
+
+diff --git a/clutter/clutter/clutter-frame-clock.c b/clutter/clutter/clutter-frame-clock.c
+index c02eb85e2..142f670f5 100644
+--- a/clutter/clutter/clutter-frame-clock.c
++++ b/clutter/clutter/clutter-frame-clock.c
+@@ -42,6 +42,15 @@ enum
+ 
+ static guint signals[N_SIGNALS];
+ 
++typedef enum
++{
++  TRIPLE_BUFFERING_MODE_NEVER,
++  TRIPLE_BUFFERING_MODE_AUTO,
++  TRIPLE_BUFFERING_MODE_ALWAYS,
++} TripleBufferingMode;
++
++static TripleBufferingMode triple_buffering_mode = TRIPLE_BUFFERING_MODE_AUTO;
++
+ #define SYNC_DELAY_FALLBACK_FRACTION 0.875
+ 
+ #define MINIMUM_REFRESH_RATE 30.f
+@@ -911,6 +920,12 @@ void
+ clutter_frame_clock_schedule_update (ClutterFrameClock *frame_clock)
+ {
+   int64_t next_update_time_us = -1;
++  TripleBufferingMode current_mode = triple_buffering_mode;
++
++  if (current_mode == TRIPLE_BUFFERING_MODE_AUTO &&
++      (frame_clock->last_flip_hints &
++       CLUTTER_FRAME_HINT_DIRECT_SCANOUT_ATTEMPTED))
++    current_mode = TRIPLE_BUFFERING_MODE_NEVER;
+ 
+   if (frame_clock->inhibit_count > 0)
+     {
+@@ -934,20 +949,31 @@ clutter_frame_clock_schedule_update (ClutterFrameClock *frame_clock)
+     case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE_AND_SCHEDULED_NOW:
+       return;
+     case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE:
+-      if (frame_clock->last_flip_hints & CLUTTER_FRAME_HINT_DIRECT_SCANOUT_ATTEMPTED)
++      switch (current_mode)
+         {
+-          /* Force double buffering, disable triple buffering */
++        case TRIPLE_BUFFERING_MODE_NEVER:
+           frame_clock->pending_reschedule = TRUE;
+           return;
++        case TRIPLE_BUFFERING_MODE_AUTO:
++          calculate_next_update_time_us (frame_clock,
++                                         &next_update_time_us,
++                                         &frame_clock->next_presentation_time_us,
++                                         &frame_clock->next_frame_deadline_us);
++          frame_clock->is_next_presentation_time_valid =
++            (frame_clock->next_presentation_time_us != 0);
++          frame_clock->has_next_frame_deadline =
++            (frame_clock->next_frame_deadline_us != 0);
++          frame_clock->state =
++            CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE_AND_SCHEDULED;
++          break;
++        case TRIPLE_BUFFERING_MODE_ALWAYS:
++          next_update_time_us = g_get_monotonic_time ();
++          frame_clock->next_presentation_time_us = 0;
++          frame_clock->is_next_presentation_time_valid = FALSE;
++          frame_clock->state =
++            CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE_AND_SCHEDULED;
++          break;
+         }
+-
+-      calculate_next_update_time_us (frame_clock,
+-                                     &next_update_time_us,
+-                                     &frame_clock->next_presentation_time_us,
+-                                     &frame_clock->next_frame_deadline_us);
+-      frame_clock->is_next_presentation_time_valid =
+-        (frame_clock->next_presentation_time_us != 0);
+-      frame_clock->state = CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE_AND_SCHEDULED;
+       break;
+     case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_TWO:
+       frame_clock->pending_reschedule = TRUE;
+@@ -1389,6 +1415,15 @@ static void
+ clutter_frame_clock_class_init (ClutterFrameClockClass *klass)
+ {
+   GObjectClass *object_class = G_OBJECT_CLASS (klass);
++  const char *mode_str;
++
++  mode_str = g_getenv ("MUTTER_DEBUG_TRIPLE_BUFFERING");
++  if (!g_strcmp0 (mode_str, "never"))
++    triple_buffering_mode = TRIPLE_BUFFERING_MODE_NEVER;
++  else if (!g_strcmp0 (mode_str, "auto"))
++    triple_buffering_mode = TRIPLE_BUFFERING_MODE_AUTO;
++  else if (!g_strcmp0 (mode_str, "always"))
++    triple_buffering_mode = TRIPLE_BUFFERING_MODE_ALWAYS;
+ 
+   object_class->dispose = clutter_frame_clock_dispose;
+ 
+-- 
+2.45.0
+
+
+From 98b65e3c59979f616e5ff99b3eda8d1375a59e23 Mon Sep 17 00:00:00 2001
+From: Daniel van Vugt <daniel.van.vugt@canonical.com>
+Date: Thu, 30 Jun 2022 18:56:06 +0800
+Subject: [PATCH 28/34] tests/native-kms-render: Fix failing client-scanout
+ test
+
+It was assuming an immediate transition from compositing (triple
+buffering) to direct scanout (double buffering), whereas there is
+a one frame delay in that transition as the buffer queue shrinks.
+We don't lose any frames in the transition.
+---
+ src/tests/native-kms-render.c | 106 ++++++++++++++++++++++++++++------
+ 1 file changed, 87 insertions(+), 19 deletions(-)
+
 diff --git a/src/tests/native-kms-render.c b/src/tests/native-kms-render.c
-index f5ebc23fec7590fd559c64049363024a06883bcd..2f870fdc331bf818b6215907d3828196b713d30f 100644
+index f5ebc23fe..2f870fdc3 100644
 --- a/src/tests/native-kms-render.c
 +++ b/src/tests/native-kms-render.c
 @@ -39,6 +39,8 @@
@@ -1878,3 +2576,496 @@ index f5ebc23fec7590fd559c64049363024a06883bcd..2f870fdc331bf818b6215907d3828196
      .loop = g_main_loop_new (NULL, FALSE),
    };
  
+-- 
+2.45.0
+
+
+From e39543fb6a6daba10faa195bb7aabf276d9698db Mon Sep 17 00:00:00 2001
+From: Daniel van Vugt <daniel.van.vugt@canonical.com>
+Date: Thu, 22 Jun 2023 15:19:53 +0800
+Subject: [PATCH 29/34] onscreen/native: Avoid callbacks on "detached"
+ onscreens
+
+Detached onscreens have no valid view so avoid servicing callbacks on
+them during/after sleep mode. As previously mentioned in 45bda2d969f.
+
+Closes: https://launchpad.net/bugs/2020049
+---
+ src/backends/native/meta-onscreen-native.c | 1 +
+ 1 file changed, 1 insertion(+)
+
+diff --git a/src/backends/native/meta-onscreen-native.c b/src/backends/native/meta-onscreen-native.c
+index 65e48f2ea..b35021c4f 100644
+--- a/src/backends/native/meta-onscreen-native.c
++++ b/src/backends/native/meta-onscreen-native.c
+@@ -1525,6 +1525,7 @@ try_post_latest_swap (CoglOnscreen *onscreen)
+   MetaFrameNative *frame_native;
+ 
+   if (onscreen_native->next_post.frame == NULL ||
++      onscreen_native->view == NULL ||
+       meta_kms_is_shutting_down (kms))
+     return;
+ 
+-- 
+2.45.0
+
+
+From 7f334ef6c6d33baffad04887affe5583524393a0 Mon Sep 17 00:00:00 2001
+From: Daniel van Vugt <daniel.van.vugt@canonical.com>
+Date: Tue, 18 Jul 2023 16:08:25 +0800
+Subject: [PATCH 30/34] clutter/frame-clock: Record measurements of zero for
+ cursor-only updates
+
+But only if we've ever got actual swap measurements
+(COGL_FEATURE_ID_TIMESTAMP_QUERY). If it's supported then we now drop to
+double buffering and get optimal latency on a burst of cursor-only
+updates.
+
+Closes: https://launchpad.net/bugs/2023363
+---
+ clutter/clutter/clutter-frame-clock.c | 28 +++++++++++++++------------
+ 1 file changed, 16 insertions(+), 12 deletions(-)
+
+diff --git a/clutter/clutter/clutter-frame-clock.c b/clutter/clutter/clutter-frame-clock.c
+index 142f670f5..eed8fd2a8 100644
+--- a/clutter/clutter/clutter-frame-clock.c
++++ b/clutter/clutter/clutter-frame-clock.c
+@@ -260,10 +260,6 @@ static void
+ maybe_update_longterm_max_duration_us (ClutterFrameClock *frame_clock,
+                                        ClutterFrameInfo  *frame_info)
+ {
+-  /* Do not update long-term max if there has been no measurement */
+-  if (!frame_clock->shortterm_max_update_duration_us)
+-    return;
+-
+   if ((frame_info->presentation_time - frame_clock->longterm_promotion_us) <
+       G_USEC_PER_SEC)
+     return;
+@@ -382,8 +378,9 @@ clutter_frame_clock_notify_presented (ClutterFrameClock *frame_clock,
+ 
+   frame_clock->got_measurements_last_frame = FALSE;
+ 
+-  if (frame_info->cpu_time_before_buffer_swap_us != 0 &&
+-      frame_info->has_valid_gpu_rendering_duration)
++  if ((frame_info->cpu_time_before_buffer_swap_us != 0 &&
++       frame_info->has_valid_gpu_rendering_duration) ||
++      frame_clock->ever_got_measurements)
+     {
+       int64_t dispatch_to_swap_us, swap_to_rendering_done_us, swap_to_flip_us;
+       int64_t dispatch_time_us = 0, flip_time_us = 0;
+@@ -408,14 +405,21 @@ clutter_frame_clock_notify_presented (ClutterFrameClock *frame_clock,
+           break;
+         }
+ 
+-      dispatch_to_swap_us =
+-        frame_info->cpu_time_before_buffer_swap_us -
+-        dispatch_time_us;
++      if (frame_info->cpu_time_before_buffer_swap_us == 0)
++        {
++          /* Cursor-only updates with no "swap" or "flip" */
++          dispatch_to_swap_us = 0;
++          swap_to_flip_us = 0;
++        }
++      else
++        {
++          dispatch_to_swap_us = frame_info->cpu_time_before_buffer_swap_us -
++                                dispatch_time_us;
++          swap_to_flip_us = flip_time_us -
++                            frame_info->cpu_time_before_buffer_swap_us;
++        }
+       swap_to_rendering_done_us =
+         frame_info->gpu_rendering_duration_ns / 1000;
+-      swap_to_flip_us =
+-        flip_time_us -
+-        frame_info->cpu_time_before_buffer_swap_us;
+ 
+       CLUTTER_NOTE (FRAME_TIMINGS,
+                     "%s: update2dispatch %ld µs, dispatch2swap %ld µs, swap2render %ld µs, swap2flip %ld µs",
+-- 
+2.45.0
+
+
+From 295a866d5810b39bcab0e4fe0f7a31d9f0befebd Mon Sep 17 00:00:00 2001
+From: Daniel van Vugt <daniel.van.vugt@canonical.com>
+Date: Wed, 26 Jul 2023 17:27:10 +0800
+Subject: [PATCH 31/34] backends/native: Make await_flush later and inlined
+
+"Later" as in after GL is finished rendering so as to not block the deadline
+timer from updating the cursor smoothly during long GL renders. Indeed this
+could make a primary plane frame late in some cases but that's only when
+going from idle to active, so there is no previous frame to observe stutter
+within the primary plane. It does however fix observable stutter in the
+cursor plane by not dropping/stalling an otherwise good cursor update in a
+continuous stream of cursor updates.
+
+"Inlined" as in we don't need most of `meta_kms_device_await_flush`. The
+important part is that it calls `disarm_crtc_frame_deadline_timer` to avoid
+attempting two posts at once. So that's all that is kept.
+
+This also fixes a deadlock in triple buffering. By not cancelling the
+cursor update during a GL render we're also not cancelling a primary plane
+update that might have already been piggybacked onto it by `queue_update`.
+
+Cherry picked from !3149
+---
+ src/backends/native/meta-kms-impl-device.c | 4 +++-
+ src/backends/native/meta-onscreen-native.c | 4 ----
+ 2 files changed, 3 insertions(+), 5 deletions(-)
+
+diff --git a/src/backends/native/meta-kms-impl-device.c b/src/backends/native/meta-kms-impl-device.c
+index b15eee14d..05bc89e83 100644
+--- a/src/backends/native/meta-kms-impl-device.c
++++ b/src/backends/native/meta-kms-impl-device.c
+@@ -1559,9 +1559,11 @@ meta_kms_impl_device_handle_update (MetaKmsImplDevice *impl_device,
+       meta_kms_update_merge_from (crtc_frame->pending_update, update);
+       meta_kms_update_free (update);
+       update = g_steal_pointer (&crtc_frame->pending_update);
+-      disarm_crtc_frame_deadline_timer (crtc_frame);
+     }
+ 
++  if (crtc_frame->deadline.armed)
++    disarm_crtc_frame_deadline_timer (crtc_frame);
++
+   meta_kms_device_handle_flush (priv->device, latch_crtc);
+ 
+   feedback = do_process (impl_device, latch_crtc, update, flags);
+diff --git a/src/backends/native/meta-onscreen-native.c b/src/backends/native/meta-onscreen-native.c
+index b35021c4f..9836663d0 100644
+--- a/src/backends/native/meta-onscreen-native.c
++++ b/src/backends/native/meta-onscreen-native.c
+@@ -1899,11 +1899,7 @@ meta_onscreen_native_before_redraw (CoglOnscreen *onscreen,
+                                     ClutterFrame *frame)
+ {
+   MetaOnscreenNative *onscreen_native = META_ONSCREEN_NATIVE (onscreen);
+-  MetaCrtcKms *crtc_kms = META_CRTC_KMS (onscreen_native->crtc);
+-  MetaKmsCrtc *kms_crtc = meta_crtc_kms_get_kms_crtc (crtc_kms);
+ 
+-  meta_kms_device_await_flush (meta_kms_crtc_get_device (kms_crtc),
+-                               kms_crtc);
+   maybe_update_frame_sync (onscreen_native, frame);
+ }
+ 
+-- 
+2.45.0
+
+
+From 2602e42ca255847123a567deb30dd51431fecb64 Mon Sep 17 00:00:00 2001
+From: Daniel van Vugt <daniel.van.vugt@canonical.com>
+Date: Wed, 17 Jan 2024 17:21:03 +0800
+Subject: [PATCH 32/34] clutter/frame-clock: Optimize latency for platforms
+ missing TIMESTAMP_QUERY
+
+Previously if we had no measurements then `compute_max_render_time_us`
+would pessimise its answer to ensure triple buffering could be reached:
+```
+if (frame_clock->state == CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE)
+  ret += refresh_interval_us;
+```
+But that also meant entering triple buffering even when not required.
+
+Now we make `compute_max_render_time_us` more honest and return failure
+if the answer isn't known (or is disabled). This in turn allows us to
+optimize `calculate_next_update_time_us` for this special case, ensuring
+triple buffering can be used, but isn't blindly always used.
+
+This makes a visible difference to the latency when dragging windows in
+Xorg, but will also help Wayland sessions on platforms lacking
+TIMESTAMP_QUERY such as Raspberry Pi.
+---
+ clutter/clutter/clutter-frame-clock.c | 69 +++++++++++++++++----------
+ 1 file changed, 45 insertions(+), 24 deletions(-)
+
+diff --git a/clutter/clutter/clutter-frame-clock.c b/clutter/clutter/clutter-frame-clock.c
+index eed8fd2a8..a6c7ecea2 100644
+--- a/clutter/clutter/clutter-frame-clock.c
++++ b/clutter/clutter/clutter-frame-clock.c
+@@ -513,25 +513,18 @@ clutter_frame_clock_notify_ready (ClutterFrameClock *frame_clock)
+     }
+ }
+ 
+-static int64_t
+-clutter_frame_clock_compute_max_render_time_us (ClutterFrameClock *frame_clock)
++static gboolean
++clutter_frame_clock_compute_max_render_time_us (ClutterFrameClock *frame_clock,
++                                                int64_t           *max_render_time_us)
+ {
+   int64_t refresh_interval_us;
+-  int64_t max_render_time_us;
+ 
+   refresh_interval_us = frame_clock->refresh_interval_us;
+ 
+   if (!frame_clock->ever_got_measurements ||
+       G_UNLIKELY (clutter_paint_debug_flags &
+                   CLUTTER_DEBUG_DISABLE_DYNAMIC_MAX_RENDER_TIME))
+-    {
+-      int64_t ret = refresh_interval_us * SYNC_DELAY_FALLBACK_FRACTION;
+-
+-      if (frame_clock->state == CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE)
+-        ret += refresh_interval_us;
+-
+-      return ret;
+-    }
++    return FALSE;
+ 
+   /* Max render time shows how early the frame clock needs to be dispatched
+    * to make it to the predicted next presentation time. It is an estimate of
+@@ -545,15 +538,15 @@ clutter_frame_clock_compute_max_render_time_us (ClutterFrameClock *frame_clock)
+    * - The duration of vertical blank.
+    * - A constant to account for variations in the above estimates.
+    */
+-  max_render_time_us =
++  *max_render_time_us =
+     MAX (frame_clock->longterm_max_update_duration_us,
+          frame_clock->shortterm_max_update_duration_us) +
+     frame_clock->vblank_duration_us +
+     clutter_max_render_time_constant_us;
+ 
+-  max_render_time_us = CLAMP (max_render_time_us, 0, 2 * refresh_interval_us);
++  *max_render_time_us = CLAMP (*max_render_time_us, 0, 2 * refresh_interval_us);
+ 
+-  return max_render_time_us;
++  return TRUE;
+ }
+ 
+ static void
+@@ -570,6 +563,7 @@ calculate_next_update_time_us (ClutterFrameClock *frame_clock,
+   int64_t next_presentation_time_us;
+   int64_t next_smooth_presentation_time_us = 0;
+   int64_t next_update_time_us;
++  gboolean max_render_time_is_known;
+ 
+   now_us = g_get_monotonic_time ();
+ 
+@@ -589,10 +583,13 @@ calculate_next_update_time_us (ClutterFrameClock *frame_clock,
+     }
+ 
+   min_render_time_allowed_us = refresh_interval_us / 2;
+-  max_render_time_allowed_us =
+-    clutter_frame_clock_compute_max_render_time_us (frame_clock);
+ 
+-  if (min_render_time_allowed_us > max_render_time_allowed_us)
++  max_render_time_is_known =
++    clutter_frame_clock_compute_max_render_time_us (frame_clock,
++                                                    &max_render_time_allowed_us);
++
++  if (max_render_time_is_known &&
++      min_render_time_allowed_us > max_render_time_allowed_us)
+     min_render_time_allowed_us = max_render_time_allowed_us;
+ 
+   /*
+@@ -712,6 +709,24 @@ calculate_next_update_time_us (ClutterFrameClock *frame_clock,
+     }
+   else
+     {
++      /* If the max render time isn't known then using the current value of
++       * next_presentation_time_us is suboptimal. Targeting always one frame
++       * prior to that we'd lose the ability to scale up to triple buffering
++       * on late presentation. But targeting two frames prior we would be
++       * always triple buffering even when not required.
++       *   So the algorithm for deciding when to scale up to triple buffering
++       * in the absence of render time measurements is to simply target full
++       * frame rate. If we're keeping up then we'll stay double buffering. If
++       * we're not keeping up then this will switch us to triple buffering.
++       */
++      if (!max_render_time_is_known)
++        {
++          max_render_time_allowed_us =
++            refresh_interval_us * SYNC_DELAY_FALLBACK_FRACTION;
++          next_presentation_time_us =
++            last_presentation_time_us + refresh_interval_us;
++        }
++
+       while (next_presentation_time_us - min_render_time_allowed_us < now_us)
+         next_presentation_time_us += refresh_interval_us;
+ 
+@@ -743,7 +758,9 @@ calculate_next_variable_update_time_us (ClutterFrameClock *frame_clock,
+ 
+   refresh_interval_us = frame_clock->refresh_interval_us;
+ 
+-  if (frame_clock->last_presentation_time_us == 0)
++  if (frame_clock->last_presentation_time_us == 0 ||
++      !clutter_frame_clock_compute_max_render_time_us (frame_clock,
++                                                       &max_render_time_allowed_us))
+     {
+       *out_next_update_time_us =
+         frame_clock->last_dispatch_time_us ?
+@@ -756,9 +773,6 @@ calculate_next_variable_update_time_us (ClutterFrameClock *frame_clock,
+       return;
+     }
+ 
+-  max_render_time_allowed_us =
+-    clutter_frame_clock_compute_max_render_time_us (frame_clock);
+-
+   last_presentation_time_us = frame_clock->last_presentation_time_us;
+   next_presentation_time_us = last_presentation_time_us + refresh_interval_us;
+ 
+@@ -1224,12 +1238,19 @@ clutter_frame_clock_record_flip (ClutterFrameClock *frame_clock,
+ GString *
+ clutter_frame_clock_get_max_render_time_debug_info (ClutterFrameClock *frame_clock)
+ {
++  int64_t max_render_time_us;
+   int64_t max_update_duration_us;
+   GString *string;
+ 
+-  string = g_string_new (NULL);
+-  g_string_append_printf (string, "Max render time: %ld µs",
+-                          clutter_frame_clock_compute_max_render_time_us (frame_clock));
++  string = g_string_new ("Max render time: ");
++  if (!clutter_frame_clock_compute_max_render_time_us (frame_clock,
++                                                       &max_render_time_us))
++    {
++      g_string_append (string, "unknown");
++      return string;
++    }
++
++  g_string_append_printf (string, "%ld µs", max_render_time_us);
+ 
+   if (frame_clock->got_measurements_last_frame)
+     g_string_append_printf (string, " =");
+-- 
+2.45.0
+
+
+From 04e002f472ef46e258f8c971f157644e170d84e2 Mon Sep 17 00:00:00 2001
+From: Daniel van Vugt <daniel.van.vugt@canonical.com>
+Date: Wed, 24 Apr 2024 18:21:01 +0800
+Subject: [PATCH 33/34] clutter/frame-clock: Break a feedback loop between VRR
+ and triple buffering
+
+VRR calls `clutter_frame_clock_schedule_update_now` which would keep
+the buffer queue full, which in turn prevented direct scanout mode.
+Because OnscreenNative currently only supports direct scanout with
+double buffering.
+
+We now break that feedback loop by preventing triple buffering from
+being scheduled when the frame clock mode becomes variable.
+
+Long term this could also be solved by supporting triple buffering in
+direct scanout mode. But whether or not that would be optimal given
+the latency penalty remains to be seen.
+---
+ clutter/clutter/clutter-frame-clock.c | 31 ++++++++++++++++++++++++---
+ 1 file changed, 28 insertions(+), 3 deletions(-)
+
+diff --git a/clutter/clutter/clutter-frame-clock.c b/clutter/clutter/clutter-frame-clock.c
+index a6c7ecea2..129d4f533 100644
+--- a/clutter/clutter/clutter-frame-clock.c
++++ b/clutter/clutter/clutter-frame-clock.c
+@@ -875,6 +875,25 @@ clutter_frame_clock_uninhibit (ClutterFrameClock *frame_clock)
+     maybe_reschedule_update (frame_clock);
+ }
+ 
++static gboolean
++want_triple_buffering (ClutterFrameClock *frame_clock)
++{
++  switch (triple_buffering_mode)
++    {
++    case TRIPLE_BUFFERING_MODE_NEVER:
++      return FALSE;
++    case TRIPLE_BUFFERING_MODE_AUTO:
++      return frame_clock->mode == CLUTTER_FRAME_CLOCK_MODE_FIXED &&
++             !(frame_clock->last_flip_hints &
++               CLUTTER_FRAME_HINT_DIRECT_SCANOUT_ATTEMPTED);
++    case TRIPLE_BUFFERING_MODE_ALWAYS:
++      return TRUE;
++    }
++
++  g_assert_not_reached ();
++  return FALSE;
++}
++
+ void
+ clutter_frame_clock_schedule_update_now (ClutterFrameClock *frame_clock)
+ {
+@@ -897,12 +916,19 @@ clutter_frame_clock_schedule_update_now (ClutterFrameClock *frame_clock)
+     case CLUTTER_FRAME_CLOCK_STATE_SCHEDULED_NOW:
+     case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE_AND_SCHEDULED_NOW:
+       return;
+-    case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE:
+     case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE_AND_SCHEDULED:
+       next_update_time_us = g_get_monotonic_time ();
+       frame_clock->state =
+         CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE_AND_SCHEDULED_NOW;
+       break;
++    case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE:
++      if (want_triple_buffering (frame_clock))
++        {
++          frame_clock->state =
++            CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE_AND_SCHEDULED_NOW;
++          break;
++        }
++      G_GNUC_FALLTHROUGH;
+     case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_TWO:
+       frame_clock->pending_reschedule = TRUE;
+       frame_clock->pending_reschedule_now = TRUE;
+@@ -941,8 +967,7 @@ clutter_frame_clock_schedule_update (ClutterFrameClock *frame_clock)
+   TripleBufferingMode current_mode = triple_buffering_mode;
+ 
+   if (current_mode == TRIPLE_BUFFERING_MODE_AUTO &&
+-      (frame_clock->last_flip_hints &
+-       CLUTTER_FRAME_HINT_DIRECT_SCANOUT_ATTEMPTED))
++      !want_triple_buffering (frame_clock))
+     current_mode = TRIPLE_BUFFERING_MODE_NEVER;
+ 
+   if (frame_clock->inhibit_count > 0)
+-- 
+2.45.0
+
+
+From 663f19bc02c1b4e3d1a67b4ad72d644f9b9d6970 Mon Sep 17 00:00:00 2001
+From: Daniel van Vugt <daniel.van.vugt@canonical.com>
+Date: Wed, 24 Apr 2024 18:42:54 +0800
+Subject: [PATCH 34/34] clutter/frame-clock: Remove some redundant logic
+
+Which became unused with the introduction of VRR.
+---
+ clutter/clutter/clutter-frame-clock.c | 12 ++----------
+ 1 file changed, 2 insertions(+), 10 deletions(-)
+
+diff --git a/clutter/clutter/clutter-frame-clock.c b/clutter/clutter/clutter-frame-clock.c
+index 129d4f533..6bd83101e 100644
+--- a/clutter/clutter/clutter-frame-clock.c
++++ b/clutter/clutter/clutter-frame-clock.c
+@@ -917,7 +917,6 @@ clutter_frame_clock_schedule_update_now (ClutterFrameClock *frame_clock)
+     case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE_AND_SCHEDULED_NOW:
+       return;
+     case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE_AND_SCHEDULED:
+-      next_update_time_us = g_get_monotonic_time ();
+       frame_clock->state =
+         CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE_AND_SCHEDULED_NOW;
+       break;
+@@ -998,14 +997,6 @@ clutter_frame_clock_schedule_update (ClutterFrameClock *frame_clock)
+           frame_clock->pending_reschedule = TRUE;
+           return;
+         case TRIPLE_BUFFERING_MODE_AUTO:
+-          calculate_next_update_time_us (frame_clock,
+-                                         &next_update_time_us,
+-                                         &frame_clock->next_presentation_time_us,
+-                                         &frame_clock->next_frame_deadline_us);
+-          frame_clock->is_next_presentation_time_valid =
+-            (frame_clock->next_presentation_time_us != 0);
+-          frame_clock->has_next_frame_deadline =
+-            (frame_clock->next_frame_deadline_us != 0);
+           frame_clock->state =
+             CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE_AND_SCHEDULED;
+           break;
+@@ -1015,7 +1006,7 @@ clutter_frame_clock_schedule_update (ClutterFrameClock *frame_clock)
+           frame_clock->is_next_presentation_time_valid = FALSE;
+           frame_clock->state =
+             CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_ONE_AND_SCHEDULED;
+-          break;
++          goto got_update_time;
+         }
+       break;
+     case CLUTTER_FRAME_CLOCK_STATE_DISPATCHED_TWO:
+@@ -1043,6 +1034,7 @@ clutter_frame_clock_schedule_update (ClutterFrameClock *frame_clock)
+       break;
+     }
+ 
++got_update_time:
+   g_warn_if_fail (next_update_time_us != -1);
+ 
+   frame_clock->next_update_time_us = next_update_time_us;
+-- 
+2.45.0
+