drm/i915: Disable stolen memory when DMAR is active
drm/i915: Disable stolen memory when DMAR is active

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 <711c73f64afdce07b7e38039a96d2224209e9a6c@chris-wilson.co.uk>
Reviewed-by: Daniel Vetter <c1b6782c4af8f0673da8923a0702a1832e5940f4@ffwll.ch>
Cc: 4fbacc2fa0ffdbb11bf1ad6925b886ebd08dd15f@vger.kernel.org
Signed-off-by: Jani Nikula <ba783f3beccaedfda693f41a15407d612a629408@intel.com>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs