Hi Chris, > > On Thu, Mar 26, 2020 at 02:27:27PM +0000, Chris Wilson wrote: > > > Userptr causes lockdep to complain when we are using the aliasing-ppgtt > > > (and ggtt, but for that it is rightfully so to complain about) in that > > > when we revoke the userptr we take a mutex which we also use to revoke > > > the mmaps. However, we only revoke mmaps for GGTT bindings and we never > > > allow userptr to create a GGTT binding so the warning should be false > > > and is simply caused by our conflation of the aliasing-ppgtt with the > > > ggtt. So lets try treating the binding into the aliasing-ppgtt as a > > > separate lockclass from the ggtt. The downside is that we are > > > deliberately suppressing lockdep;s ability to warn us of cycles. > > ^^^^ > > typo > > > > > > > > Closes: https://gitlab.freedesktop.org/drm/intel/issues/478 > > > > I'm not a big fan of links in commit messages, I think they would > > be forbidden by law, but I'm not being picky on that. > > I'm lazy, I take clickable links. > > > I don't know, thogh, why your S-o-b is missing. > > I felt uncomfortable with this hack, but it passes CI (but it may be > suppressing too much -- I think the code is safe at the moment, but we > may lose our sensitivity to future bugs). We can only hope in CI critical cases are covered well enough... in the worst case we can always revert it. Andi _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
