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Commit 9c23f7fc authored by Chris Wilson's avatar Chris Wilson Committed by Keith Packard
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drm/i915: Do not clflush snooped objects 



Rely on the GPU snooping into the CPU cache for appropriately bound
objects on MI_FLUSH. Or perhaps one day we will have a cache-coherent
CPU/GPU package...

Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: default avatarEric Anholt <eric@anholt.net>
Reviewed-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: default avatarKeith Packard <keithp@keithp.com>
parent 93dfb40c

drivers/gpu/drm/i915/i915_gem.c

+11 −0
Original line number Diff line number Diff line
@@ -2878,6 +2878,17 @@ i915_gem_clflush_object(struct drm_i915_gem_object *obj) 
	if (obj->pages == NULL)

		return;



	/* If the GPU is snooping the contents of the CPU cache,

	 * we do not need to manually clear the CPU cache lines.  However,

	 * the caches are only snooped when the render cache is

	 * flushed/invalidated.  As we always have to emit invalidations

	 * and flushes when moving into and out of the RENDER domain, correct

	 * snooping behaviour occurs naturally as the result of our domain

	 * tracking.

	 */

	if (obj->cache_level != I915_CACHE_NONE)

		return;



	trace_i915_gem_object_clflush(obj);



	drm_clflush_pages(obj->pages, obj->base.size / PAGE_SIZE);