diff options
Diffstat (limited to 'i915-vga-arbiter.patch')
| -rw-r--r-- | i915-vga-arbiter.patch | 186 |
1 files changed, 186 insertions, 0 deletions
diff --git a/i915-vga-arbiter.patch b/i915-vga-arbiter.patch new file mode 100644 index 000000000000..abc906b513f8 --- /dev/null +++ b/i915-vga-arbiter.patch @@ -0,0 +1,186 @@ +From 7209b38ae2b81e6d79aecb77263580f8840e459a Mon Sep 17 00:00:00 2001 +From: Mark Weiman <mark.weiman@markzz.com> +Date: Wed, 7 Feb 2018 19:50:27 -0500 +Subject: [PATCH] i915: Add module option to support VGA arbiter on HD devices + (4.15) + +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. + +Signed-off-by: Mark Weiman <mark.weiman@markzz.com> +--- + drivers/gpu/drm/i915/i915_drv.c | 22 +++++++++++++++++++--- + drivers/gpu/drm/i915/i915_params.c | 3 +++ + drivers/gpu/drm/i915/i915_params.h | 1 + + drivers/gpu/drm/i915/intel_display.c | 33 +++++++++++++++++++++++++++++++++ + drivers/gpu/drm/i915/intel_drv.h | 1 + + 5 files changed, 57 insertions(+), 3 deletions(-) + +diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c +index 2cf10d17acfb..794590a2dcf3 100644 +--- a/drivers/gpu/drm/i915/i915_drv.c ++++ b/drivers/gpu/drm/i915/i915_drv.c +@@ -641,10 +641,20 @@ 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_modparams.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(); + +@@ -686,6 +696,12 @@ 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 b4faeb6aa2bd..fdf2ce69b34d 100644 +--- a/drivers/gpu/drm/i915/i915_params.c ++++ b/drivers/gpu/drm/i915/i915_params.c +@@ -146,6 +146,9 @@ i915_param_named(disable_display, bool, 0400, + i915_param_named_unsafe(enable_cmd_parser, bool, 0400, + "Enable command parsing (true=enabled [default], false=disabled)"); + ++i915_param_named(enable_hd_vgaarb, bool, 0444, ++ "Enable support for VGA arbitration on Intel HD IGD. (default: false)"); ++ + i915_param_named(mmio_debug, int, 0600, + "Enable the MMIO debug code for the first N failures (default: off). " + "This may negatively affect performance."); +diff --git a/drivers/gpu/drm/i915/i915_params.h b/drivers/gpu/drm/i915/i915_params.h +index c7292268ed43..75577d34b0c8 100644 +--- a/drivers/gpu/drm/i915/i915_params.h ++++ b/drivers/gpu/drm/i915/i915_params.h +@@ -56,6 +56,7 @@ + /* leave bools at the end to not create holes */ \ + param(bool, alpha_support, IS_ENABLED(CONFIG_DRM_I915_ALPHA_SUPPORT)) \ + param(bool, enable_cmd_parser, true) \ ++ param(bool, enable_hd_vgaarb, false) \ + param(bool, enable_hangcheck, true) \ + param(bool, fastboot, false) \ + param(bool, prefault_disable, false) \ +diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c +index 50f8443641b8..06aebb05f23c 100644 +--- a/drivers/gpu/drm/i915/intel_display.c ++++ b/drivers/gpu/drm/i915/intel_display.c +@@ -14379,6 +14379,36 @@ 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_modparams.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_modparams.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); +@@ -14877,6 +14907,7 @@ 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); + } + } + +@@ -15252,6 +15283,8 @@ 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 5d77f75a9f9c..982fff761e9d 100644 +--- a/drivers/gpu/drm/i915/intel_drv.h ++++ b/drivers/gpu/drm/i915/intel_drv.h +@@ -1340,6 +1340,7 @@ 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, +-- +2.16.1 + |