This reverts commit 25ff119 and the follow on for Valleyview commit 2dc8aae.
commit 25ff1195f8
Author: Chris Wilson <chris@chris-wilson.co.uk>
Date: Thu Apr 4 21:31:03 2013 +0100
drm/i915: Workaround incoherence between fences and LLC across multiple CPUs
commit 2dc8aae06d
Author: Chris Wilson <chris@chris-wilson.co.uk>
Date: Wed May 22 17:08:06 2013 +0100
drm/i915: Workaround incoherence with fence updates on Valleyview
Jon Bloomfield came up with a plausible explanation and cheap fix
(drm/i915: Fix incoherence with fence updates on Sandybridge+) for the
race condition, so lets run with it.
This is a candidate for stable as the old workaround incurs a
significant cost (calling wbinvd on all CPUs before performing the
register write) for some workloads as noted by Carsten Emde.
Link: http://lists.freedesktop.org/archives/intel-gfx/2013-June/028819.html
References: https://www.osadl.org/?id=1543#c7602
References: https://bugs.freedesktop.org/show_bug.cgi?id=63825
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Jon Bloomfield <jon.bloomfield@intel.com>
Cc: Carsten Emde <C.Emde@osadl.org>
Cc: stable@vger.kernel.org
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
46a0b638f3