On Wed, Jun 02, 2021 at 11:41:44AM -0500, Jason Ekstrand wrote: > Fence error propagation is sketchy at best. Instead of explicitly handling > fences which might have errors set in the code which is aware of errors, we > just kick them down the line and hope that userspace knows what to do when > a wait eventually fails. This is sketchy at best because most userspace > isn't prepared to handle errors in those places. To make things worse, it > allows errors to propagate across processes in unpredictable ways. This is > causing hangs in one client to kill X11. > > Unfortunately, there's no quick path from here to there thanks to the fact > that we're now running the command parser asynchronously and relying on > fence errors for when it fails. This series first gets rid of asynchronous > command parsing and then cleans up from there. There was never any real > use-case for asynchronous parsing and the platforms that rely heavily on > the command parser are old enough (Gen7) that, when we changed the way the > command parser works, it wasn't really a change anyone was asking for > anyway. > > I think we probably want this whole mess back-ported. I'm happy to take > suggestions on the strategy there because the history there is a bit > annoying and I'm not 100% sure where the Linux release cuts land. In any > case, I'm happy to make a version of this series per-release if needed for > Greg to back-port. I think just the two reversts are enough to be backported, other 3 are cleanups. Also I guess this will need to come with an igt patch to adjust the cmdparser test. With all the nits addressed, on the series. Acked-by: Daniel Vetter <daniel.vetter@xxxxxxxx> > > Cc: Daniel Vetter <daniel.vetter@xxxxxxxx> > Cc: Jon Bloomfield <jon.bloomfield@xxxxxxxxx> > > Jason Ekstrand (5): > drm/i915: Revert "drm/i915/gem: Asynchronous cmdparser" > drm/i915: Remove allow_alloc from i915_gem_object_get_sg* > drm/i915: Drop error handling from dma_fence_work > Revert "drm/i915: Propagate errors on awaiting already signaled > fences" > Revert "drm/i915: Skip over MI_NOOP when parsing" > > drivers/gpu/drm/i915/gem/i915_gem_clflush.c | 4 +- > .../gpu/drm/i915/gem/i915_gem_execbuffer.c | 227 +----------------- > drivers/gpu/drm/i915/gem/i915_gem_object.h | 10 +- > drivers/gpu/drm/i915/gem/i915_gem_pages.c | 21 +- > .../i915/gem/selftests/i915_gem_execbuffer.c | 4 + > drivers/gpu/drm/i915/gt/intel_ggtt.c | 2 +- > drivers/gpu/drm/i915/i915_cmd_parser.c | 199 ++++++++------- > drivers/gpu/drm/i915/i915_drv.h | 7 +- > drivers/gpu/drm/i915/i915_request.c | 8 +- > drivers/gpu/drm/i915/i915_sw_fence_work.c | 5 +- > drivers/gpu/drm/i915/i915_sw_fence_work.h | 2 +- > drivers/gpu/drm/i915/i915_vma.c | 3 +- > 12 files changed, 141 insertions(+), 351 deletions(-) > > -- > 2.31.1 > -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch
