From: John Harrison <[email protected]> Direction from hardware is that ring buffers should never be mapped via the BAR on systems with LLC. There are too many caching pitfalls due to the way BAR accesses are routed. So it is safest to just not use it.
Signed-off-by: John Harrison <[email protected]> Fixes: 9d80841ea4c9 ("drm/i915: Allow ringbuffers to be bound anywhere") Cc: Chris Wilson <[email protected]> Cc: Joonas Lahtinen <[email protected]> Cc: Jani Nikula <[email protected]> Cc: Rodrigo Vivi <[email protected]> Cc: Tvrtko Ursulin <[email protected]> Cc: [email protected] Cc: <[email protected]> # v4.9+ Tested-by: Jouni Högander <[email protected]> Reviewed-by: Daniele Ceraolo Spurio <[email protected]> Link: https://patchwork.freedesktop.org/patch/msgid/[email protected] (cherry picked from commit 65c08339db1ada87afd6cfe7db8e60bb4851d919) Signed-off-by: Jani Nikula <[email protected]> (cherry picked from commit 85636167e3206c3fbd52254fc432991cc4e90194) Signed-off-by: John Harrison <[email protected]> --- drivers/gpu/drm/i915/gt/intel_ringbuffer.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/i915/gt/intel_ringbuffer.c b/drivers/gpu/drm/i915/gt/intel_ringbuffer.c index eee9fcbe0434..808269b2108f 100644 --- a/drivers/gpu/drm/i915/gt/intel_ringbuffer.c +++ b/drivers/gpu/drm/i915/gt/intel_ringbuffer.c @@ -1208,7 +1208,7 @@ int intel_ring_pin(struct intel_ring *ring) if (unlikely(ret)) goto err_unpin; - if (i915_vma_is_map_and_fenceable(vma)) + if (i915_vma_is_map_and_fenceable(vma) && !HAS_LLC(vma->vm->i915)) addr = (void __force *)i915_vma_pin_iomap(vma); else addr = i915_gem_object_pin_map(vma->obj, @@ -1252,7 +1252,7 @@ void intel_ring_unpin(struct intel_ring *ring) intel_ring_reset(ring, ring->emit); i915_vma_unset_ggtt_write(vma); - if (i915_vma_is_map_and_fenceable(vma)) + if (i915_vma_is_map_and_fenceable(vma) && !HAS_LLC(vma->vm->i915)) i915_vma_unpin_iomap(vma); else i915_gem_object_unpin_map(vma->obj); -- 2.39.1
