Adding drm/i915 into the vga arbiter chain means that X (in a piece of well-meant paranoia) will do a get/put on the vga decoding around _every_ accel call down into the ddx. Which results in some nice performance disasters [1].
Ville tried to come up with a Great Hack to fiddle the required VGA I/O ops behind everyone's back using stop_machine, but that didn't really work out [2]. Given that we're fairly late in the -rc stage for such games let's just revert this all.
This reverts
commit 6e1b4fdad5157bb9e88777d525704aba24389bee Author: Ville Syrjälä ville.syrjala@linux.intel.com Date: Thu Sep 5 20:40:52 2013 +0300
drm/i915: Delay disabling of VGA memory until vgacon->fbcon handoff is done
and
commit 81b5c7bc8de3e6f63419139c2fc91bf81dea8a7d Author: Alex Williamson alex.williamson@redhat.com Date: Wed Aug 28 09:39:08 2013 -0600
i915: Update VGA arbiter support for newer devices
One thing we might want to keep is to delay the disabling of the vga decoding until the fbdev emulation and the fbcon screen is set up. If we kill vga mem decoding beforehand fbcon can end up with a white square in the top-left corner it tried to save from the vga memory for a seamless transition. And we have bug reports on older platforms which seem to match these symptoms.
But again that's something to play around with in -next.
References: [1] http://lists.x.org/archives/xorg-devel/2013-September/037763.html References: [2] http://www.spinics.net/lists/intel-gfx/msg34062.html Cc: Alex Williamson alex.williamson@redhat.com Cc: Ville Syrjälä ville.syrjala@linux.intel.com Cc: Chris Wilson chris@chris-wilson.co.uk Signed-off-by: Daniel Vetter daniel.vetter@ffwll.ch --- drivers/gpu/drm/i915/i915_dma.c | 15 +++------------ drivers/gpu/drm/i915/intel_display.c | 30 ------------------------------ drivers/gpu/drm/i915/intel_drv.h | 1 - include/linux/vgaarb.h | 7 ------- 4 files changed, 3 insertions(+), 50 deletions(-)
diff --git a/drivers/gpu/drm/i915/i915_dma.c b/drivers/gpu/drm/i915/i915_dma.c index c27a210..d5c784d 100644 --- a/drivers/gpu/drm/i915/i915_dma.c +++ b/drivers/gpu/drm/i915/i915_dma.c @@ -1290,12 +1290,9 @@ static int i915_load_modeset_init(struct drm_device *dev) * then we do not take part in VGA arbitration and the * vga_client_register() fails with -ENODEV. */ - if (!HAS_PCH_SPLIT(dev)) { - ret = vga_client_register(dev->pdev, dev, NULL, - i915_vga_set_decode); - if (ret && ret != -ENODEV) - goto out; - } + ret = vga_client_register(dev->pdev, dev, NULL, i915_vga_set_decode); + if (ret && ret != -ENODEV) + goto out;
intel_register_dsm_handler();
@@ -1351,12 +1348,6 @@ static int i915_load_modeset_init(struct drm_device *dev) */ intel_fbdev_initial_config(dev);
- /* - * 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. */ dev_priv->enable_hotplug_processing = true;
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c index c89abd3..581fb4b 100644 --- a/drivers/gpu/drm/i915/intel_display.c +++ b/drivers/gpu/drm/i915/intel_display.c @@ -10045,33 +10045,6 @@ 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 (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 (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) { intel_init_power_well(dev); @@ -10350,7 +10323,6 @@ void i915_redisable_vga(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); } }
@@ -10564,8 +10536,6 @@ void intel_modeset_cleanup(struct drm_device *dev)
intel_disable_fbc(dev);
- i915_enable_vga_mem(dev); - intel_disable_gt_powersave(dev);
ironlake_teardown_rc6(dev); diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h index 28cae80..9b7b68f 100644 --- a/drivers/gpu/drm/i915/intel_drv.h +++ b/drivers/gpu/drm/i915/intel_drv.h @@ -793,6 +793,5 @@ extern void hsw_pc8_disable_interrupts(struct drm_device *dev); extern void hsw_pc8_restore_interrupts(struct drm_device *dev); extern void intel_aux_display_runtime_get(struct drm_i915_private *dev_priv); extern void intel_aux_display_runtime_put(struct drm_i915_private *dev_priv); -extern void i915_disable_vga_mem(struct drm_device *dev);
#endif /* __INTEL_DRV_H__ */ diff --git a/include/linux/vgaarb.h b/include/linux/vgaarb.h index 80cf817..2c02f3a 100644 --- a/include/linux/vgaarb.h +++ b/include/linux/vgaarb.h @@ -65,15 +65,8 @@ struct pci_dev; * out of the arbitration process (and can be safe to take * interrupts at any time. */ -#if defined(CONFIG_VGA_ARB) extern void vga_set_legacy_decoding(struct pci_dev *pdev, unsigned int decodes); -#else -static inline void vga_set_legacy_decoding(struct pci_dev *pdev, - unsigned int decodes) -{ -} -#endif
/** * vga_get - acquire & locks VGA resources