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From c3ef7b73136fa897006d5b11de8a68962000bc22 Mon Sep 17 00:00:00 2001
From: xiota <>
Date: Fri, 10 Oct 2025 11:24:47 +0000
Subject: [PATCH] i915-vga-arbiter
---
.../drm/i915/display/intel_display_driver.c | 18 ++++++++--
.../drm/i915/display/intel_display_driver.h | 1 +
.../drm/i915/display/intel_display_params.c | 3 ++
.../drm/i915/display/intel_display_params.h | 1 +
drivers/gpu/drm/i915/display/intel_vga.c | 34 +++++++++++++++++++
drivers/gpu/drm/i915/display/intel_vga.h | 4 +++
.../gpu/drm/xe/compat-i915-headers/i915_drv.h | 6 ++++
7 files changed, 64 insertions(+), 3 deletions(-)
diff --git a/drivers/gpu/drm/i915/display/intel_display_driver.c b/drivers/gpu/drm/i915/display/intel_display_driver.c
index 8586ba102..5c8ce811a 100644
--- a/drivers/gpu/drm/i915/display/intel_display_driver.c
+++ b/drivers/gpu/drm/i915/display/intel_display_driver.c
@@ -31,6 +31,7 @@
#include "intel_display_debugfs.h"
#include "intel_display_driver.h"
#include "intel_display_irq.h"
+#include "intel_display_params.h"
#include "intel_display_power.h"
#include "intel_display_types.h"
#include "intel_display_wa.h"
@@ -219,9 +220,11 @@ int intel_display_driver_probe_noirq(struct intel_display *display)
intel_bios_init(display);
- ret = intel_vga_register(display);
- if (ret)
- goto cleanup_bios;
+ if (!display->params.enable_hd_vgaarb || !HAS_PCH_SPLIT(i915)) {
+ ret = intel_vga_register(display);
+ if (ret)
+ goto cleanup_bios;
+ }
intel_psr_dc5_dc6_wa_init(display);
@@ -552,6 +555,12 @@ int intel_display_driver_probe(struct intel_display *display)
intel_overlay_setup(display);
+ /*
+ * Must do this after fbcon init so that
+ * vgacon_save_screen() works during the handover.
+ */
+ intel_vga_disable_mem(display);
+
/* Only enable hotplug handling once the fbdev is fully set up. */
intel_hpd_init(display);
@@ -602,6 +611,8 @@ void intel_display_driver_remove(struct intel_display *display)
if (!HAS_DISPLAY(display))
return;
+ intel_vga_enable_mem(display);
+
flush_workqueue(display->wq.flip);
flush_workqueue(display->wq.modeset);
flush_workqueue(display->wq.cleanup);
@@ -632,6 +643,7 @@ void intel_display_driver_remove_noirq(struct intel_display *display)
intel_unregister_dsm_handler();
/* flush any delayed tasks or pending work */
+ intel_vga_enable_mem(display);
flush_workqueue(display->wq.unordered);
intel_hdcp_component_fini(display);
diff --git a/drivers/gpu/drm/i915/display/intel_display_driver.h b/drivers/gpu/drm/i915/display/intel_display_driver.h
index 2966ff91b..ca0dc7577 100644
--- a/drivers/gpu/drm/i915/display/intel_display_driver.h
+++ b/drivers/gpu/drm/i915/display/intel_display_driver.h
@@ -13,6 +13,7 @@ struct drm_modeset_acquire_ctx;
struct intel_display;
struct pci_dev;
+extern void intel_vga_disable_mem(struct intel_display *display);
bool intel_display_driver_probe_defer(struct pci_dev *pdev);
void intel_display_driver_init_hw(struct intel_display *display);
void intel_display_driver_early_probe(struct intel_display *display);
diff --git a/drivers/gpu/drm/i915/display/intel_display_params.c b/drivers/gpu/drm/i915/display/intel_display_params.c
index 75316247e..844176964 100644
--- a/drivers/gpu/drm/i915/display/intel_display_params.c
+++ b/drivers/gpu/drm/i915/display/intel_display_params.c
@@ -102,6 +102,9 @@ intel_display_param_named_unsafe(force_reset_modeset_test, bool, 0400,
intel_display_param_named(disable_display, bool, 0400,
"Disable display (default: false)");
+intel_display_param_named(enable_hd_vgaarb, bool, 0400,
+ "Enable support for VGA arbitration on Intel HD IGD. (default: false)");
+
intel_display_param_named(verbose_state_checks, bool, 0400,
"Enable verbose logs (ie. WARN_ON()) in case of unexpected hw state conditions.");
diff --git a/drivers/gpu/drm/i915/display/intel_display_params.h b/drivers/gpu/drm/i915/display/intel_display_params.h
index 784e6bae8..23e697cbe 100644
--- a/drivers/gpu/drm/i915/display/intel_display_params.h
+++ b/drivers/gpu/drm/i915/display/intel_display_params.h
@@ -41,6 +41,7 @@ struct drm_printer;
param(bool, load_detect_test, false, 0600) \
param(bool, force_reset_modeset_test, false, 0600) \
param(bool, disable_display, false, 0400) \
+ param(bool, enable_hd_vgaarb, false, 0400) \
param(bool, verbose_state_checks, true, 0400) \
param(bool, nuclear_pageflip, false, 0400) \
param(bool, enable_dp_mst, true, 0600) \
diff --git a/drivers/gpu/drm/i915/display/intel_vga.c b/drivers/gpu/drm/i915/display/intel_vga.c
index 6e125564d..3921e27be 100644
--- a/drivers/gpu/drm/i915/display/intel_vga.c
+++ b/drivers/gpu/drm/i915/display/intel_vga.c
@@ -13,8 +13,10 @@
#include "soc/intel_gmch.h"
+#include "i915_drv.h"
#include "intel_de.h"
#include "intel_display.h"
+#include "intel_display_params.h"
#include "intel_vga.h"
#include "intel_vga_regs.h"
@@ -76,6 +78,38 @@ void intel_vga_disable(struct intel_display *display)
intel_de_posting_read(display, vga_reg);
}
+void intel_vga_enable_mem(struct intel_display *display)
+{
+ struct pci_dev *pdev = to_pci_dev(display->drm->dev);
+ struct drm_i915_private *i915 = pdev_to_i915(pdev);
+ /* Enable VGA memory on Intel HD */
+ if (display->params.enable_hd_vgaarb && HAS_PCH_SPLIT(i915)) {
+ vga_get_uninterruptible(pdev, VGA_RSRC_LEGACY_IO);
+ outb(inb(VGA_MIS_R) | (1 << 1), VGA_MIS_W);
+ vga_set_legacy_decoding(pdev, VGA_RSRC_LEGACY_IO |
+ VGA_RSRC_LEGACY_MEM |
+ VGA_RSRC_NORMAL_IO |
+ VGA_RSRC_NORMAL_MEM);
+ vga_put(pdev, VGA_RSRC_LEGACY_IO);
+ }
+}
+
+void intel_vga_disable_mem(struct intel_display *display)
+{
+ struct pci_dev *pdev = to_pci_dev(display->drm->dev);
+ struct drm_i915_private *i915 = pdev_to_i915(pdev);
+ /* Disable VGA memory on Intel HD */
+ if (display->params.enable_hd_vgaarb && HAS_PCH_SPLIT(i915)) {
+ vga_get_uninterruptible(pdev, VGA_RSRC_LEGACY_IO);
+ outb(inb(VGA_MIS_R) & ~(1 << 1), VGA_MIS_W);
+ vga_set_legacy_decoding(pdev, VGA_RSRC_LEGACY_IO |
+ VGA_RSRC_NORMAL_IO |
+ VGA_RSRC_NORMAL_MEM);
+ vga_put(pdev, VGA_RSRC_LEGACY_IO);
+ }
+}
+
+
void intel_vga_reset_io_mem(struct intel_display *display)
{
struct pci_dev *pdev = to_pci_dev(display->drm->dev);
diff --git a/drivers/gpu/drm/i915/display/intel_vga.h b/drivers/gpu/drm/i915/display/intel_vga.h
index 16d699f3b..d91a6cf67 100644
--- a/drivers/gpu/drm/i915/display/intel_vga.h
+++ b/drivers/gpu/drm/i915/display/intel_vga.h
@@ -13,4 +13,8 @@ void intel_vga_disable(struct intel_display *display);
int intel_vga_register(struct intel_display *display);
void intel_vga_unregister(struct intel_display *display);
+/* i915 vga arb patch */
+void intel_vga_enable_mem(struct intel_display *display);
+void intel_vga_disable_mem(struct intel_display *display);
+
#endif /* __INTEL_VGA_H__ */
diff --git a/drivers/gpu/drm/xe/compat-i915-headers/i915_drv.h b/drivers/gpu/drm/xe/compat-i915-headers/i915_drv.h
index 9b7572e06..043734cf0 100644
--- a/drivers/gpu/drm/xe/compat-i915-headers/i915_drv.h
+++ b/drivers/gpu/drm/xe/compat-i915-headers/i915_drv.h
@@ -21,6 +21,12 @@ static inline struct drm_i915_private *to_i915(const struct drm_device *dev)
return container_of(dev, struct drm_i915_private, drm);
}
+static inline struct drm_i915_private *pdev_to_i915(struct pci_dev *pdev)
+{
+ struct drm_device *drm = pci_get_drvdata(pdev);
+ return drm ? to_i915(drm) : NULL;
+}
+
/* compat platform checks only for soc/ usage */
#define IS_PLATFORM(xe, x) ((xe)->info.platform == x)
#define IS_I915G(dev_priv) (dev_priv && 0)
--
2.51.0
|