From: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> Currently it's possible to get visible cache dirt on scanout on LLC machines when using pwrite on the future scanout bo if its cache_level is already NONE. pwrite's "does this need clflush?" checks would decide that no clflush is necessary since the bo isn't currently pinned to the display and LLC makes everything else coherent. The subsequent set_cache_level(NONE) would also do nothing since cache_level is already correct. And hence no clflush will be performed and we flip to a bo which can still have dirty data in the caches. To correctly track the cache dirtyness move the object to CPU write domain in pwrite. This cures the cache dirt since we explicitly flush the CPU write domain in the pin_to_display path. Give pread the same treatment simply in the name of symmetry. v2: Use trace_i915_gem_object_change_domain() and provide some kind of commit message Cc: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> Signed-off-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> --- v1 was floated on irc. drivers/gpu/drm/i915/i915_gem.c | 32 +++++++++++++++++++++++++++++++- 1 file changed, 31 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c index 3e0cabe..12a3c16 100644 --- a/drivers/gpu/drm/i915/i915_gem.c +++ b/drivers/gpu/drm/i915/i915_gem.c @@ -456,6 +456,7 @@ __copy_from_user_swizzled(char *gpu_vaddr, int gpu_offset, int i915_gem_obj_prepare_shmem_read(struct drm_i915_gem_object *obj, int *needs_clflush) { + u32 old_read_domains; int ret; *needs_clflush = 0; @@ -475,6 +476,7 @@ int i915_gem_obj_prepare_shmem_read(struct drm_i915_gem_object *obj, return ret; i915_gem_object_retire(obj); + i915_gem_object_flush_gtt_write_domain(obj); } ret = i915_gem_object_get_pages(obj); @@ -483,6 +485,13 @@ int i915_gem_obj_prepare_shmem_read(struct drm_i915_gem_object *obj, i915_gem_object_pin_pages(obj); + old_read_domains = obj->base.read_domains; + obj->base.read_domains |= I915_GEM_DOMAIN_CPU; + + trace_i915_gem_object_change_domain(obj, + old_read_domains, + obj->base.write_domain); + return ret; } @@ -875,6 +884,7 @@ i915_gem_shmem_pwrite(struct drm_device *dev, int needs_clflush_after = 0; int needs_clflush_before = 0; struct sg_page_iter sg_iter; + u32 old_write_domain, old_read_domains; user_data = to_user_ptr(args->data_ptr); remain = args->size; @@ -892,6 +902,7 @@ i915_gem_shmem_pwrite(struct drm_device *dev, return ret; i915_gem_object_retire(obj); + i915_gem_object_flush_gtt_write_domain(obj); } /* Same trick applies to invalidate partially written cachelines read * before writing. */ @@ -908,6 +919,15 @@ i915_gem_shmem_pwrite(struct drm_device *dev, offset = args->offset; obj->dirty = 1; + old_read_domains = obj->base.read_domains; + old_write_domain = obj->base.write_domain; + obj->base.read_domains = I915_GEM_DOMAIN_CPU; + obj->base.write_domain = I915_GEM_DOMAIN_CPU; + + trace_i915_gem_object_change_domain(obj, + old_read_domains, + old_write_domain); + for_each_sg_page(obj->pages->sgl, &sg_iter, obj->pages->nents, offset >> PAGE_SHIFT) { struct page *page = sg_page_iter_page(&sg_iter); @@ -978,9 +998,19 @@ out: } } - if (needs_clflush_after) + if (needs_clflush_after) { i915_gem_chipset_flush(dev); + if (obj->base.write_domain == I915_GEM_DOMAIN_CPU) { + old_write_domain = obj->base.write_domain; + obj->base.write_domain = 0; + + trace_i915_gem_object_change_domain(obj, + obj->base.read_domains, + old_write_domain); + } + } + return ret; } -- 2.0.4 _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/intel-gfx