From: John Harrison John.C.Harrison@Intel.com
Direction from hardware is that stolen memory should never be used for ring buffer allocations on platforms with LLC. There are too many caching pitfalls due to the way stolen memory accesses are routed. So it is safest to just not use it.
Signed-off-by: John Harrison John.C.Harrison@Intel.com Fixes: c58b735fc762 ("drm/i915: Allocate rings from stolen") Cc: Chris Wilson chris@chris-wilson.co.uk Cc: Joonas Lahtinen joonas.lahtinen@linux.intel.com Cc: Jani Nikula jani.nikula@linux.intel.com Cc: Rodrigo Vivi rodrigo.vivi@intel.com Cc: Tvrtko Ursulin tvrtko.ursulin@linux.intel.com Cc: intel-gfx@lists.freedesktop.org Cc: stable@vger.kernel.org # v4.9+ Tested-by: Jouni Högander jouni.hogander@intel.com Reviewed-by: Daniele Ceraolo Spurio daniele.ceraolospurio@intel.com Link: https://patchwork.freedesktop.org/patch/msgid/20230216011101.1909009-2-John.... (cherry picked from commit f54c1f6c697c4297f7ed94283c184acc338a5cf8) Signed-off-by: Jani Nikula jani.nikula@intel.com (cherry picked from commit 690e0ec8e63da9a29b39fedc6ed5da09c7c82651) Signed-off-by: John Harrison John.C.Harrison@Intel.com --- drivers/gpu/drm/i915/gt/intel_ring.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/i915/gt/intel_ring.c b/drivers/gpu/drm/i915/gt/intel_ring.c index 7c4d5158e03b..7d82545d15e5 100644 --- a/drivers/gpu/drm/i915/gt/intel_ring.c +++ b/drivers/gpu/drm/i915/gt/intel_ring.c @@ -113,7 +113,7 @@ static struct i915_vma *create_ring_vma(struct i915_ggtt *ggtt, int size) struct i915_vma *vma;
obj = i915_gem_object_create_lmem(i915, size, I915_BO_ALLOC_VOLATILE); - if (IS_ERR(obj) && i915_ggtt_has_aperture(ggtt)) + if (IS_ERR(obj) && i915_ggtt_has_aperture(ggtt) && !HAS_LLC(i915)) obj = i915_gem_object_create_stolen(i915, size); if (IS_ERR(obj)) obj = i915_gem_object_create_internal(i915, size);