On 16/02/2023 01:10, [email protected] wrote:
From: John Harrison <[email protected]>

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).
v3: Fix dumb typo.

Signed-off-by: John Harrison <[email protected]>


John Harrison (2):
   drm/i915: Don't use stolen memory for ring buffers with LLC
   drm/i915: Don't use BAR mappings for ring buffers with LLC

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

It is doing what it laid out as the problem statement so series looks good to me.

Acked-by: Tvrtko Ursulin <[email protected]>

Regards,

Tvrtko


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