From 44d8022a2ff1e71bffba431877949ecf827ea9f2 Mon Sep 17 00:00:00 2001 From: Dan Ziemba Date: Mon, 13 Jun 2016 18:09:36 -0400 Subject: [PATCH] Updated i915 vga arbiter patch for 4.6.2 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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: Alex Williamson Cc: Ville Syrjälä Cc: Daniel Vetter Cc: Dave Airlie --- drivers/gpu/drm/i915/i915_dma.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 | 30 ++++++++++++++++++++++++++++++ drivers/gpu/drm/i915/intel_drv.h | 2 ++ 5 files changed, 57 insertions(+), 3 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_dma.c b/drivers/gpu/drm/i915/i915_dma.c index 1c6d227..43bce33 100644 --- a/drivers/gpu/drm/i915/i915_dma.c +++ b/drivers/gpu/drm/i915/i915_dma.c @@ -380,10 +380,20 @@ 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 only 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(dev->pdev, dev, NULL, i915_vga_set_decode); - if (ret && ret != -ENODEV) - goto out; + if (!i915.enable_hd_vgaarb || !HAS_PCH_SPLIT(dev)) { + ret = vga_client_register(dev->pdev, dev, NULL, + i915_vga_set_decode); + if (ret && ret != -ENODEV) + goto out; + } intel_register_dsm_handler(); @@ -423,6 +433,12 @@ 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); + /* 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 278c9c4..e0a3e08 100644 --- a/drivers/gpu/drm/i915/i915_params.c +++ b/drivers/gpu/drm/i915/i915_params.c @@ -49,6 +49,7 @@ struct i915_params i915 __read_mostly = { .invert_brightness = 0, .disable_display = 0, .enable_cmd_parser = 1, + .enable_hd_vgaarb = false, .use_mmio_flip = 0, .mmio_debug = 0, .verbose_state_checks = 1, @@ -171,6 +172,10 @@ module_param_named_unsafe(enable_cmd_parser, i915.enable_cmd_parser, int, 0600); MODULE_PARM_DESC(enable_cmd_parser, "Enable command parsing (1=enabled [default], 0=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 bd5026b..f7c9769 100644 --- a/drivers/gpu/drm/i915/i915_params.h +++ b/drivers/gpu/drm/i915/i915_params.h @@ -56,6 +56,7 @@ struct i915_params { bool load_detect_test; bool reset; bool disable_display; + bool enable_hd_vgaarb; bool enable_guc_submission; bool verbose_state_checks; bool nuclear_pageflip; diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c index 7741efb..ddb94bb 100644 --- a/drivers/gpu/drm/i915/intel_display.c +++ b/drivers/gpu/drm/i915/intel_display.c @@ -15252,6 +15252,33 @@ static void i915_disable_vga(struct drm_device *dev) POSTING_READ(vga_reg); } +static void i915_enable_vga_mem(struct drm_device *dev) +{ + /* Enable VGA memory on Intel HD */ + if (i915.enable_hd_vgaarb && HAS_PCH_SPLIT(dev)) { + vga_get_uninterruptible(dev->pdev, VGA_RSRC_LEGACY_IO); + outb(inb(VGA_MSR_READ) | VGA_MSR_MEM_EN, VGA_MSR_WRITE); + vga_set_legacy_decoding(dev->pdev, VGA_RSRC_LEGACY_IO | + VGA_RSRC_LEGACY_MEM | + VGA_RSRC_NORMAL_IO | + VGA_RSRC_NORMAL_MEM); + vga_put(dev->pdev, VGA_RSRC_LEGACY_IO); + } +} + +void i915_disable_vga_mem(struct drm_device *dev) +{ + /* Disable VGA memory on Intel HD */ + if (i915.enable_hd_vgaarb && HAS_PCH_SPLIT(dev)) { + vga_get_uninterruptible(dev->pdev, VGA_RSRC_LEGACY_IO); + outb(inb(VGA_MSR_READ) & ~VGA_MSR_MEM_EN, VGA_MSR_WRITE); + vga_set_legacy_decoding(dev->pdev, VGA_RSRC_LEGACY_IO | + VGA_RSRC_NORMAL_IO | + VGA_RSRC_NORMAL_MEM); + vga_put(dev->pdev, VGA_RSRC_LEGACY_IO); + } +} + void intel_modeset_init_hw(struct drm_device *dev) { struct drm_i915_private *dev_priv = dev->dev_private; @@ -15689,6 +15716,7 @@ void i915_redisable_vga_power_on(struct drm_device *dev) if (!(I915_READ(vga_reg) & VGA_DISP_DISABLE)) { DRM_DEBUG_KMS("Something enabled VGA plane, disabling it\n"); i915_disable_vga(dev); + i915_disable_vga_mem(dev); } } @@ -16074,6 +16102,8 @@ void intel_modeset_cleanup(struct drm_device *dev) struct drm_i915_private *dev_priv = dev->dev_private; struct intel_connector *connector; + i915_enable_vga_mem(dev); + intel_disable_gt_powersave(dev); intel_backlight_unregister(dev); diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h index 3a30b37..7723927 100644 --- a/drivers/gpu/drm/i915/intel_drv.h +++ b/drivers/gpu/drm/i915/intel_drv.h @@ -1623,4 +1623,6 @@ void intel_plane_destroy_state(struct drm_plane *plane, struct drm_plane_state *state); extern const struct drm_plane_helper_funcs intel_plane_helper_funcs; +extern void i915_disable_vga_mem(struct drm_device *dev); + #endif /* __INTEL_DRV_H__ */ -- 2.8.3