On Thu, Jul 27, 2023 at 03:55:03PM +0100, Tvrtko Ursulin wrote: > From: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx> > > Now that i915 understands the caching modes behind PAT indices, we can > refine the check in use_cpu_reloc() to not reject the uncached PAT if it > was set by userspace. > > Instead it can decide based on the presence of full coherency which > should be functionally equivalent on legacy platforms. We can ignore WT > since it is only used by the display, and we can ignore Meteorlake since > it will fail on the existing "has_llc" condition before the object cache > mode check. > > Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx> > Cc: Fei Yang <fei.yang@xxxxxxxxx> > Cc: Matt Roper <matthew.d.roper@xxxxxxxxx> > --- > drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c | 9 +-------- > 1 file changed, 1 insertion(+), 8 deletions(-) > > diff --git a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c > index 9d6e49c8a4c6..f74b33670bad 100644 > --- a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c > +++ b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c > @@ -640,16 +640,9 @@ static inline int use_cpu_reloc(const struct reloc_cache *cache, > if (DBG_FORCE_RELOC == FORCE_GTT_RELOC) > return false; > > - /* > - * For objects created by userspace through GEM_CREATE with pat_index > - * set by set_pat extension, i915_gem_object_has_cache_level() always > - * return true, otherwise the call would fall back to checking whether > - * the object is un-cached. > - */ > return (cache->has_llc || > obj->cache_dirty || > - !(obj->pat_set_by_user || > - i915_gem_object_has_cache_mode(obj, I915_CACHE_MODE_UC))); > + i915_gem_object_has_cache_flag(obj, I915_CACHE_FLAG_COH2W)); My understanding of relocations is minimal, but does 2W actually matter here (CPU snooping GPU caches)? I would have expected only 1W coherency to be necessary (GPU snooping CPU caches)? Matt > } > > static int eb_reserve_vma(struct i915_execbuffer *eb, > -- > 2.39.2 > -- Matt Roper Graphics Software Engineer Linux GPU Platform Enablement Intel Corporation
