drm/i915: skip the first 4k of stolen memory on everything >= gen8
authorPaulo Zanoni <paulo.r.zanoni@intel.com>
Wed, 14 Dec 2016 14:55:37 +0000 (12:55 -0200)
committerJani Nikula <jani.nikula@intel.com>
Tue, 20 Dec 2016 14:30:55 +0000 (16:30 +0200)
commit6ba0566cf2afcdb17bff882e3a95cbbcb22c4a83
treef4c29f8d4ddf8cb67483194d6b98a2d8fb872e16
parentabb0deacb5a6713b918ac6395182cb27bb88be69
drm/i915: skip the first 4k of stolen memory on everything >= gen8

BSpec got updated and this workaround is now listed as standard
required programming for all subsequent projects. This is confirmed to
fix Skylake screen flickering issues (probably caused by the fact that
we initialized a ring in the first page of stolen, but I didn't 100%
confirm this theory).

v2: this is the patch that fixes the screen flickering, document it.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=94605
Cc: stable@vger.kernel.org
Tested-by: Dominik Klementowski <dominik232@gmail.com>
Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Acked-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1481727338-9901-1-git-send-email-paulo.r.zanoni@intel.com
(cherry picked from commit d43537610470d8829ebd17cd7842f47176e35ebd)
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
drivers/gpu/drm/i915/i915_gem_stolen.c