On Wed, 2023-02-15 at 17:10 -0800, John.C.Harrison@xxxxxxxxx wrote: > From: John Harrison <John.C.Harrison@xxxxxxxxx> > > 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. Tested these patches for GPU Hang I was debugging. Seem to fix that one as well: Tested-by: Jouni Högander <jouni.hogander@xxxxxxxxx> > > 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 <John.C.Harrison@xxxxxxxxx> > > > 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(-) >
