On Wed, Aug 14, 2013 at 10:49:11AM +0200, Daniel Vetter wrote: > On Tue, Aug 13, 2013 at 03:37:56PM +0300, Ville Syrjälä wrote: > > On Tue, Aug 13, 2013 at 01:20:13PM +0100, Chris Wilson wrote: > > > On Tue, Aug 13, 2013 at 03:12:59PM +0300, Ville Syrjälä wrote: > > > > Thinking about this stuff a bit, I think I actually came up with a > > > > scenario where we would currently fail to invalidate the CPU cache > > > > between non-snooped GPU/GTT access and CPU access: > > > > > > > > 1. make bo non-snooped w/ pin_display=true (wd=0, rd|=gtt) > > > > 2. set to CPU read domain (wd=0 rd|=cpu) > > > > 3. set to GTT (or GPU) write domain (wd=gtt, rd=gtt) -> CPU cache is stale after this point > > > > 4. make bo snooped -> pin_display=true still so we directly set (wd=cpu, rd=cpu) > > > > 5. set to CPU domain -> CPU cache is still stale > > > > > > You will also find the scanout reads stale data as well. > > > > Well, assuming you actually write something to the bo w/ the CPU. If > > not, then it keeps scanning out the correct data. > > I think an if (obj->pin_display) return -EBUSY; in the set_caching ioctl > would be good to fix this. And we already do that check (as a result of obj->pin_count). Sorted. -Chris -- Chris Wilson, Intel Open Source Technology Centre _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/intel-gfx
