On Tue, Dec 14, 2010 at 12:55:59PM +0800, Zhenyu Wang wrote: > It appears Sandybridge PIPE_CONTROL write out buffer need > to be set as cached, currently LLC cached, in order to read > back correct counter. Otherwise I can always be possible to > get corrupted 64-bit PS_DEPTH_COUNT from PIPE_CONTROL write. > > So below patches try to add new flag during bo create with > cacheable type, to be sure that GTT entry's cache bits would > be setup for that. > > This fixes occlusion query piglit test and mesa demos on my > sandybridge. Note that below patches don't include necessary > component version check changes.
General comment on the introduction of a new flag for bo creation: If I'm not mistaken, all the query objects are relocated as read_domain = I915_GEM_DOMAIN_INSTRUCTION, write_domain = I915_GEM_DOMAIN_INSTRUCTION, i.e. we already have an api for userspace to tell us that a PIPE_CONTROL command will write to this buffer. Why can't we use that one and remap the bo with the correct caching flags on execbuf time (on gen6)? I simply fear that introducing a hacky ad-hoc abi complicates matters when we introduce real llc/mlc caching for general stuff. Especially since there's seems to be an existing thing already available. I'm still fighting the fallout from the incoherent multiple rings introduction and I just don't want to repeat such a goof-up. Yours, Daniel -- Daniel Vetter Mail: dan...@ffwll.ch Mobile: +41 (0)79 365 57 48 _______________________________________________ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/intel-gfx
