drm/i915: Make contexts non-snooped on non-LLC platforms (ad2ac08b) · Commits · e / devices / android_kernel_teracube_2e

We don't do CPU access to GPU contexts so making the GPU access snoop the CPU caches seems silly, and potentially expensive. v2: Use !IS_VALLEYVIEW instead of HAS_LLC as this is really about what the PTEs can represent. Add a comment clarifying the situation. Signed-off-by:

Ville Syrjälä <ville.syrjala@linux.intel.com> Reviewed-by:

Chris Wilson <chris@chris-wilson.co.uk> Signed-off-by:

Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/i915_gem_context.c

+9 −1

Original line number	Diff line number	Diff line
		@@ -240,7 +240,15 @@ __create_hw_context(struct drm_device *dev,
		return ERR_PTR(-ENOMEM);
		}

		if (INTEL_INFO(dev)->gen >= 7) {
		/*
		* Try to make the context utilize L3 as well as LLC.
		*
		* On VLV we don't have L3 controls in the PTEs so we
		* shouldn't touch the cache level, especially as that
		* would make the object snooped which might have a
		* negative performance impact.
		*/
		if (INTEL_INFO(dev)->gen >= 7 && !IS_VALLEYVIEW(dev)) {
		ret = i915_gem_object_set_cache_level(ctx->obj,
		I915_CACHE_L3_LLC);
		/* Failure shouldn't ever happen this early */