drm/i915: Mark CPU cache as dirty when used for rendering
authorChris Wilson <chris@chris-wilson.co.uk>
Mon, 7 Nov 2016 16:52:04 +0000 (16:52 +0000)
committerChris Wilson <chris@chris-wilson.co.uk>
Mon, 7 Nov 2016 20:54:39 +0000 (20:54 +0000)
commit7aa6ca61ee5546d74b76610894924cdb0d4a1af0
treea109c41bbe5450e4199a6316625e0fc845d1e7ed
parent31ab49abde41c4056b17ca3d63456a62964834c0
drm/i915: Mark CPU cache as dirty when used for rendering

On LLC, or even snooped, machines rendering via the GPU ends up in the CPU
cache. This cacheline dirt also needs to be flushed to main memory when
moving to an incoherent domain, such as the display's scanout engine.
Mostly, this happens because either the object is marked as dirty from
its first use or is avoided by setting the object into the display
domain from the start.

v2: Treat WT as not requiring a clflush prior to use on the display
engine as well.

Fixes: 0f71979ab7fb ("drm/i915: Performed deferred clflush inside set-cache-level")
References: https://bugs.freedesktop.org/show_bug.cgi?id=95414
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: <stable@vger.kernel.org> # v4.0+
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20161107165204.7008-1-chris@chris-wilson.co.uk
drivers/gpu/drm/i915/i915_gem_execbuffer.c