On 1/15/21 4:56 PM, Chris Wilson wrote: > Quoting Jinoh Kang (2021-01-15 16:23:31) >> If GUP-ineligible pages are passed to a GEM userptr object, -EFAULT is >> returned only when the object is actually bound. >> >> The xf86-video-intel userspace driver cannot differentiate this >> condition, and marks the GPU as wedged. > > The idea was to call gem_set_domain on the object to validate the pages > after creation. I only did that for read-only... I did however make mesa > use set-domain for validation. Thanks for the info! > > As a question how are you getting to call userptr on something that > wasn't passed by SHM ipc? Basically XShmAttachFd, which is not exposed on libX11. > >> This not only disables graphics >> acceleration but may also cripple other functions such as VT switch. > > That should be a non-sequitur; certainly VT switch works without ever > using the GPU. Not that VT switch doesn't work; rather, there's some heavy graphic artifacts such as blank rectangles or part of window going completely transparent. I suppose that's another issue. > >> Solve this by "prefaulting" user pages on GEM object creation, testing >> whether all pages are eligible for get_user_pages() in the process. >> On failure, return -EFAULT so that userspace can fallback to software >> blitting. > > See https://patchwork.freedesktop.org/series/33449/ for adding PROBE | > POPULATE flags. > > But we can just use set-domain. So this patch was unnecessary. Thanks for the pointer as to how to patch the userspace. > -Chris > -- Sincerely, Jinoh Kang _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
