[Intel-gfx] [PATCH 5.15.y] drm/i915: Don't use stolen memory for ring buffers with LLC

[Intel-gfx] [PATCH 5.15.y] drm/i915: Don't use stolen memory for ring buffers with LLC

[John.C.Harrison]

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.C.Harrison@Intel.com
(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);
-- 
2.39.1

[Intel-gfx] ✗ Fi.CI.BUILD: failure for drm/i915: Don't use stolen memory for ring buffers with LLC (rev5)

[Patchwork]

== Series Details ==

Series: drm/i915: Don't use stolen memory for ring buffers with LLC (rev5)
URL   : https://patchwork.freedesktop.org/series/115334/
State : failure

== Summary ==

Error: patch https://patchwork.freedesktop.org/api/1.0/series/115334/revisions/5/mbox/ not applied
Applying: drm/i915: Don't use stolen memory for ring buffers with LLC
Using index info to reconstruct a base tree...
M	drivers/gpu/drm/i915/gt/intel_ring.c
Falling back to patching base and 3-way merge...
Auto-merging drivers/gpu/drm/i915/gt/intel_ring.c
CONFLICT (content): Merge conflict in drivers/gpu/drm/i915/gt/intel_ring.c
error: Failed to merge in the changes.
hint: Use 'git am --show-current-patch=diff' to see the failed patch
Patch failed at 0001 drm/i915: Don't use stolen memory for ring buffers with LLC
When you have resolved this problem, run "git am --continue".
If you prefer to skip this patch, run "git am --skip" instead.
To restore the original branch and stop patching, run "git am --abort".
Build failed, no error log produced