drm/i915: Allow the GPU to cache stolen memory

As a corollary to reviewing the interaction between LLC and our cache
domains, the GPU PTE bits are independent of the CPU PAT bits. As such
we can set the cache level on stolen memory based on how we wish the GPU
to cache accesses to it. So we are free to set the same default cache
levels as for normal bo, i.e. enable LLC cacheing by default where
appropriate.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

diff --git a/drivers/gpu/drm/i915/i915_gem_stolen.c b/drivers/gpu/drm/i915/i915_gem_stolen.c
index e68c4b5da46db95baae18412c01818214abe9811..e20d64966c72d3839eabb295c9655a6cec956fcb 100644 (file)
--- a/drivers/gpu/drm/i915/i915_gem_stolen.c
+++ b/drivers/gpu/drm/i915/i915_gem_stolen.c
@@ -287,9 +287,8 @@ _i915_gem_object_create_stolen(struct drm_device *dev,
        i915_gem_object_pin_pages(obj);
        obj->stolen = stolen;
 
-       obj->base.write_domain = I915_GEM_DOMAIN_GTT;
-       obj->base.read_domains = I915_GEM_DOMAIN_GTT;
-       obj->cache_level = I915_CACHE_NONE;
+       obj->base.read_domains = I915_GEM_DOMAIN_CPU | I915_GEM_DOMAIN_GTT;
+       obj->cache_level = HAS_LLC(dev) ? I915_CACHE_LLC : I915_CACHE_NONE;
 
        return obj;