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Chris Wilson authored
As mentioned in the previous commit, reads and writes from both the CPU and GPU go through the LLC. This gives us coherency between the CPU and GPU irrespective of the attribute settings either device sets. We can use to avoid having to clflush even uncached memory. Except for the scanout. The scanout resides within another functional block that does not use the LLC but reads directly from main memory. So in order to maintain coherency with the scanout, writes to uncached memory must be flushed. In order to optimize writes elsewhere, we start tracking whether an framebuffer is attached to an object. v2: Use pin_display tracking rather than fb_count (to ensure we flush cursors as well etc) and only force the clflush along explicit writes to the scanout paths (i.e. pin_to_display_plane and pwrite into scanout). v3: Force the flush after hitting the slowpath in pwrite, as after dropping the lock the object's cache domain may be invalidated. (Ville) Based on a patch by Ville Syrjälä. Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com> Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
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