[PATCH 3.11 115/144] drm/i915: Disable stolen memory when DMAR is active

From: Luis Henriques
Date: Tue Apr 01 2014 - 07:32:56 EST -stable review patch. If anyone has any objections, please let me know.


From: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>

commit 0f4706d2740f2a221cd502922b22e522009041d9 upstream.

We have reports of heavy screen corruption if we try to use the stolen
memory reserved by the BIOS whilst the DMA-Remapper is active. This
quirk may be only specific to a few machines or BIOSes, but first lets
apply the big hammer and always disable use of stolen memory when DMAR
is active.

v2 by Jani: Rebase on -fixes, only look at intel_iommu_gfx_mapped.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=68535
Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Reviewed-by: Daniel Vetter <daniel.vetter@xxxxxxxx>
Signed-off-by: Jani Nikula <jani.nikula@xxxxxxxxx>
[ luis: backported to 3.11: adjusted context ]
Signed-off-by: Luis Henriques <luis.henriques@xxxxxxxxxxxxx>
drivers/gpu/drm/i915/i915_gem_stolen.c | 7 +++++++
1 file changed, 7 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_gem_stolen.c b/drivers/gpu/drm/i915/i915_gem_stolen.c
index 4047e3b..4f04b02 100644
--- a/drivers/gpu/drm/i915/i915_gem_stolen.c
+++ b/drivers/gpu/drm/i915/i915_gem_stolen.c
@@ -191,6 +191,13 @@ int i915_gem_init_stolen(struct drm_device *dev)
struct drm_i915_private *dev_priv = dev->dev_private;
int bios_reserved = 0;

+ if (intel_iommu_gfx_mapped) {
+ DRM_INFO("DMAR active, disabling use of stolen memory\n");
+ return 0;
+ }
dev_priv->mm.stolen_base = i915_stolen_to_physical(dev);
if (dev_priv->mm.stolen_base == 0)
return 0;

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