diff options
Diffstat (limited to 'i915-vga-arbiter.patch')
| -rw-r--r-- | i915-vga-arbiter.patch | 194 |
1 files changed, 194 insertions, 0 deletions
diff --git a/i915-vga-arbiter.patch b/i915-vga-arbiter.patch new file mode 100644 index 000000000000..cdedd31811de --- /dev/null +++ b/i915-vga-arbiter.patch @@ -0,0 +1,194 @@ +From ad546a3996bf0725bb89545b4bf4656b4105221e Mon Sep 17 00:00:00 2001 +From: Mark Weiman <mark.weiman@markzz.com> +Date: Wed, 13 Dec 2017 15:38:53 -0500 +Subject: [PATCH] i915: Add module option to support VGA arbiter on HD devices + (4.14) + +This is an updated version of Alex Williamson's patch from: +https://lkml.org/lkml/2014/5/9/517 +I don't have i915 graphics, so this is completely untested. + +Original commit message follows: +--- +Commit 81b5c7bc found that the current VGA arbiter support in i915 +only works for ancient GMCH-based IGD devices and attempted to update +support for newer HD devices. Unfortunately newer devices cannot +completely opt-out of VGA arbitration like the old devices could. +The VGA I/O space cannot be disabled internally. The only way to +route VGA I/O elsewhere is by disabling I/O at the device PCI command +register. This means that with commit 81b5c7bc and multiple VGA +adapters, the VGA arbiter will report that multiple VGA devices are +participating in arbitration, Xorg will notice this and disable DRI. +Therefore, 81b5c7bc was reverted because DRI is more important than +being correct. + +There is however an actual need for i915 to correctly participate in +VGA arbitration; VGA device assignment. If we want to use VFIO to +assign a VGA device to a virtual machine, we need to be able to +access the VGA resources of that device. By adding an i915 module +option we can allow i915 to continue with its charade by default, but +also allow an easy path for users who require working VGA arbitration. +Hopefully Xorg can someday be taught to behave better with multiple +VGA devices. + +This also rolls in reverted commit 6e1b4fda, which corrected an +ordering issue with 81b5c7bc by delaying the disabling of VGA memory +until after vgacon->fbcon handoff. +--- + drivers/gpu/drm/i915/i915_drv.c | 22 +++++++++++++++++++--- + drivers/gpu/drm/i915/i915_params.c | 5 +++++ + drivers/gpu/drm/i915/i915_params.h | 1 + + drivers/gpu/drm/i915/intel_display.c | 34 ++++++++++++++++++++++++++++++++++ + drivers/gpu/drm/i915/intel_drv.h | 1 + + 5 files changed, 60 insertions(+), 3 deletions(-) + +diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c +index 82498f8232eb..13795e7cdb5f 100644 +--- a/drivers/gpu/drm/i915/i915_drv.c ++++ b/drivers/gpu/drm/i915/i915_drv.c +@@ -629,10 +629,20 @@ static int i915_load_modeset_init(struct drm_device *dev) + * If we are a secondary display controller (!PCI_DISPLAY_CLASS_VGA), + * then we do not take part in VGA arbitration and the + * vga_client_register() fails with -ENODEV. ++ * ++ * NB. The set_decode callback here actually works on GMCH ++ * devices, on newer HD devices we can only disable VGA MMIO space. ++ * Disabling VGA I/O space requires disabling I/O in the PCI command ++ * register. Nonetheless, we like to pretend that we participate in ++ * VGA arbitration and can dynamically disable VGA I/O space because ++ * this makes X happy, even though it's a complete lie. + */ +- ret = vga_client_register(pdev, dev_priv, NULL, i915_vga_set_decode); +- if (ret && ret != -ENODEV) +- goto out; ++ if (!i915.enable_hd_vgaarb || !HAS_PCH_SPLIT(dev_priv)) { ++ ret = vga_client_register(pdev, dev, NULL, ++ i915_vga_set_decode); ++ if (ret && ret != -ENODEV) ++ goto out; ++ } + + intel_register_dsm_handler(); + +@@ -674,6 +684,12 @@ static int i915_load_modeset_init(struct drm_device *dev) + if (ret) + goto cleanup_gem; + ++ /* ++ * Must do this after fbcon init so that ++ * vgacon_save_screen() works during the handover. ++ */ ++ i915_disable_vga_mem(dev_priv); ++ + /* Only enable hotplug handling once the fbdev is fully set up. */ + intel_hpd_init(dev_priv); + +diff --git a/drivers/gpu/drm/i915/i915_params.c b/drivers/gpu/drm/i915/i915_params.c +index 8ab003dca113..c1e5c6c2e24e 100644 +--- a/drivers/gpu/drm/i915/i915_params.c ++++ b/drivers/gpu/drm/i915/i915_params.c +@@ -51,6 +51,7 @@ struct i915_params i915 __read_mostly = { + .invert_brightness = 0, + .disable_display = 0, + .enable_cmd_parser = true, ++ .enable_hd_vgaarb = false, + .use_mmio_flip = 0, + .mmio_debug = 0, + .verbose_state_checks = 1, +@@ -198,6 +199,10 @@ module_param_named_unsafe(enable_cmd_parser, i915.enable_cmd_parser, bool, 0400) + MODULE_PARM_DESC(enable_cmd_parser, + "Enable command parsing (true=enabled [default], false=disabled)"); + ++module_param_named(enable_hd_vgaarb, i915.enable_hd_vgaarb, bool, 0444); ++MODULE_PARM_DESC(enable_hd_vgaarb, ++ "Enable support for VGA arbitration on Intel HD IGD. (default: false)"); ++ + module_param_named_unsafe(use_mmio_flip, i915.use_mmio_flip, int, 0600); + MODULE_PARM_DESC(use_mmio_flip, + "use MMIO flips (-1=never, 0=driver discretion [default], 1=always)"); +diff --git a/drivers/gpu/drm/i915/i915_params.h b/drivers/gpu/drm/i915/i915_params.h +index ac844709c97e..edb6633e417d 100644 +--- a/drivers/gpu/drm/i915/i915_params.h ++++ b/drivers/gpu/drm/i915/i915_params.h +@@ -64,6 +64,7 @@ + func(bool, force_reset_modeset_test); \ + func(bool, error_capture); \ + func(bool, disable_display); \ ++ func(bool, enable_hd_vgaarb); \ + func(bool, verbose_state_checks); \ + func(bool, nuclear_pageflip); \ + func(bool, enable_dp_mst); \ +diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c +index 5ebdb63330dd..f686661d4ac4 100644 +--- a/drivers/gpu/drm/i915/intel_display.c ++++ b/drivers/gpu/drm/i915/intel_display.c +@@ -14382,6 +14382,37 @@ static void i915_disable_vga(struct drm_i915_private *dev_priv) + POSTING_READ(vga_reg); + } + ++static void i915_enable_vga_mem(struct drm_i915_private *dev_priv) ++{ ++ struct pci_dev *pdev = dev_priv->drm.pdev; ++ ++ /* Enable VGA memory on Intel HD */ ++ if (i915.enable_hd_vgaarb && HAS_PCH_SPLIT(dev_priv)) { ++ vga_get_uninterruptible(pdev, VGA_RSRC_LEGACY_IO); ++ outb(inb(VGA_MSR_READ) | VGA_MSR_MEM_EN, VGA_MSR_WRITE); ++ 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 i915_disable_vga_mem(struct drm_i915_private *dev_priv) ++{ ++ struct pci_dev *pdev = dev_priv->drm.pdev; ++ ++ /* Disable VGA memory on Intel HD */ ++ if (i915.enable_hd_vgaarb && HAS_PCH_SPLIT(dev_priv)) { ++ vga_get_uninterruptible(pdev, VGA_RSRC_LEGACY_IO); ++ outb(inb(VGA_MSR_READ) & ~VGA_MSR_MEM_EN, VGA_MSR_WRITE); ++ 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_modeset_init_hw(struct drm_device *dev) + { + struct drm_i915_private *dev_priv = to_i915(dev); +@@ -14880,6 +14911,7 @@ void i915_redisable_vga_power_on(struct drm_i915_private *dev_priv) + if (!(I915_READ(vga_reg) & VGA_DISP_DISABLE)) { + DRM_DEBUG_KMS("Something enabled VGA plane, disabling it\n"); + i915_disable_vga(dev_priv); ++ i915_disable_vga_mem(dev_priv); + } + } + +@@ -15248,6 +15280,8 @@ void intel_modeset_cleanup(struct drm_device *dev) + { + struct drm_i915_private *dev_priv = to_i915(dev); + ++ i915_enable_vga_mem(dev_priv); ++ + flush_work(&dev_priv->atomic_helper.free_work); + WARN_ON(!llist_empty(&dev_priv->atomic_helper.free_list)); + +diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h +index 79fbaf78f604..c0083032a053 100644 +--- a/drivers/gpu/drm/i915/intel_drv.h ++++ b/drivers/gpu/drm/i915/intel_drv.h +@@ -1316,6 +1316,7 @@ int vlv_get_cck_clock_hpll(struct drm_i915_private *dev_priv, + const char *name, u32 reg); + void lpt_disable_pch_transcoder(struct drm_i915_private *dev_priv); + void lpt_disable_iclkip(struct drm_i915_private *dev_priv); ++extern void i915_disable_vga_mem(struct drm_i915_private *dev_priv); + void intel_init_display_hooks(struct drm_i915_private *dev_priv); + unsigned int intel_fb_xy_to_linear(int x, int y, + const struct intel_plane_state *state, +-- +2.15.1 + |