FAILED: patch "[PATCH] drm/i915: Don't use stolen memory for ring buffers with LLC" failed to apply to 5.15-stable tree

The patch below does not apply to the 5.15-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y
git checkout FETCH_HEAD
git cherry-pick -x 690e0ec8e63da9a29b39fedc6ed5da09c7c82651
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '[email protected]' --subject-prefix 'PATCH 5.15.y' HEAD^..

Possible dependencies:

690e0ec8e63d ("drm/i915: Don't use stolen memory for ring buffers with LLC") 0d8ee5ba8db4 ("drm/i915: Don't back up pinned LMEM context images and rings during suspend") c56ce9565374 ("drm/i915 Implement LMEM backup and restore for suspend / resume") 0d9388635a22 ("drm/i915/ttm: Implement a function to copy the contents of two TTM-based objects") 48b096126954 ("drm/i915: Move __i915_gem_free_object to ttm_bo_destroy") d8ac30fd479c ("drm/i915/ttm: Reorganize the ttm move code somewhat")

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 690e0ec8e63da9a29b39fedc6ed5da09c7c82651 Mon Sep 17 00:00:00 2001
From: John Harrison <[email protected]>
Date: Wed, 15 Feb 2023 17:11:00 -0800
Subject: [PATCH] drm/i915: Don't use stolen memory for ring buffers with LLC
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

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.

index 15ec64d881c4..fb1d2595392e 100644
@@ -116,7 +116,7 @@ static struct i915_vma *create_ring_vma(struct i915_ggtt *ggtt, int size)
 
 	obj = i915_gem_object_create_lmem(i915, size, I915_BO_ALLOC_VOLATILE |
 					  I915_BO_ALLOC_PM_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);

From: John Harrison <[email protected]>

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.

---
 drivers/gpu/drm/i915/gt/intel_ring.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

index 7c4d5158e03b..7d82545d15e5 100644
@@ -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