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* [Intel-gfx] [PATCH v2 0/2] Don't use stolen memory or BAR mappings for ring buffers
@ 2023-02-16  0:22 John.C.Harrison
  2023-02-16  0:22 ` [Intel-gfx] [PATCH v2 1/2] drm/i915: Don't use stolen memory for ring buffers with LLC John.C.Harrison
                   ` (2 more replies)
  0 siblings, 3 replies; 6+ messages in thread
From: John.C.Harrison @ 2023-02-16  0:22 UTC (permalink / raw)
  To: Intel-GFX; +Cc: DRI-Devel

From: John Harrison <John.C.Harrison@Intel.com>

Instruction from hardware arch is that stolen memory and BAR mappings
are unsafe for use as ring buffers. There can be issues with cache
aliasing due to the CPU access going to memory via the BAR. So, don't
do it.

v2: Dont use BAR mappings either.
Make conditional on LLC so as not to change platforms that don't need
to change (Daniele).
Add 'Fixes' tags (Tvrtko).

Signed-off-by: John Harrison <John.C.Harrison@Intel.com>


Daniele Ceraolo Spurio (1):
  drm/i915: Don't use BAR mappings for ring buffers with LLC

John Harrison (1):
  drm/i915: Don't use stolen memory for ring buffers with LLC

 drivers/gpu/drm/i915/gt/intel_ring.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

-- 
2.39.1


^ permalink raw reply	[flat|nested] 6+ messages in thread

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2023-02-16  0:22 [Intel-gfx] [PATCH v2 0/2] Don't use stolen memory or BAR mappings for ring buffers John.C.Harrison
2023-02-16  0:22 ` [Intel-gfx] [PATCH v2 1/2] drm/i915: Don't use stolen memory for ring buffers with LLC John.C.Harrison
2023-02-16  0:22 ` [Intel-gfx] [PATCH v2 2/2] drm/i915: Don't use BAR mappings " John.C.Harrison
2023-02-16  2:54   ` kernel test robot
2023-02-16  8:47   ` kernel test robot
2023-02-16  0:58 ` [Intel-gfx] ✗ Fi.CI.BUILD: failure for Don't use stolen memory or BAR mappings for ring buffers Patchwork

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