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[3/6] drm/i915: Do not clflush snooped objects

Message ID 1301443195-10721-4-git-send-email-eric@anholt.net (mailing list archive)
State New, archived
Headers show

Commit Message

Eric Anholt March 29, 2011, 11:59 p.m. UTC
None
diff mbox

Patch

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 264bec8..fa483d8 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -2878,6 +2878,14 @@  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 clear the CPU cache lines. Instead we need
+	 * to be sure to flush/invalidate the RENDER cache when the contents
+	 * must be refreshed.
+	 */
+	if (obj->cache_level != I915_CACHE_NONE)
+		return;
+
 	trace_i915_gem_object_clflush(obj);
 
 	drm_clflush_pages(obj->pages, obj->base.size / PAGE_SIZE);