From: John Harrison Date: Thu, 16 Feb 2023 01:11:00 +0000 (-0800) Subject: drm/i915: Don't use stolen memory for ring buffers with LLC X-Git-Tag: v5.15.104~8 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=71dffdd4764cb4ea013338f49731220570786118;p=thirdparty%2Fkernel%2Fstable.git drm/i915: Don't use stolen memory for ring buffers with LLC commit 690e0ec8e63da9a29b39fedc6ed5da09c7c82651 upstream. 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 Fixes: c58b735fc762 ("drm/i915: Allocate rings from stolen") Cc: Chris Wilson Cc: Joonas Lahtinen Cc: Jani Nikula Cc: Rodrigo Vivi Cc: Tvrtko Ursulin Cc: intel-gfx@lists.freedesktop.org Cc: # v4.9+ Tested-by: Jouni Högander Reviewed-by: Daniele Ceraolo Spurio Link: https://patchwork.freedesktop.org/patch/msgid/20230216011101.1909009-2-John.C.Harrison@Intel.com (cherry picked from commit f54c1f6c697c4297f7ed94283c184acc338a5cf8) Signed-off-by: Jani Nikula Signed-off-by: John Harrison Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/gpu/drm/i915/gt/intel_ring.c b/drivers/gpu/drm/i915/gt/intel_ring.c index 7c4d5158e03bb..7d82545d15e5c 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);