* Maarten Lankhorst <maarten.lankhorst@xxxxxxxxxxxxx> wrote: > > I think the Nouveau guys need to comment further on this, but > > returning -EFAULT might break existing user-space, and that's not > > allowed, but IIRC the return value of "presumed" is only a hint, and > > if it's incorrect will only trigger future command stream patching. > > > > Otherwise reviewing mostly the TTM stuff. FWIW, from wat I can tell > > the vmwgfx driver doesn't need any fixups. > > Well because we read the list of buffer objects the presumed offsets are > at least read-mapped. Although I guess in the worst case the mapping > might disappear before the syscall copies back the data. So if -EFAULT > happens here then userspace messed up in some way, either by forgetting > to map the offsets read-write, which cannot happen with libdrm or > free'ing the bo list before the syscall returns, which would probably > result in libdrm crashing shortly afterwards anyway. > > So I don't know whether to swallow that -EFAULT or not, which is what I > asked. In such a case returning -EFAULT is very strongly preferred. If there's a user-space bug, such as a context life time race between graphics context creation/destruction and user threads making use of the graphics context, then getting the -EFAULT would be very helpful to user-space debugging as well. Thanks, Ingo _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/intel-gfx
