drm/i915: Revert "drm/i915/gem: Asynchronous cmdparser"
This reverts 686c7c35 ("drm/i915/gem: Asynchronous cmdparser"). The justification for this commit in the git history was a vague comment about getting it out from under the struct_mutex. While this may improve perf for some workloads on Gen7 platforms where we rely on the command parser for features such as indirect rendering, no numbers were provided to prove such an improvement. It claims to closed two gitlab/bugzilla issues but with no explanation whatsoever as to why or what bug it's fixing. Meanwhile, by moving command parsing off to an async callback, it leaves us with a problem of what to do on error. When things were synchronous, EXECBUFFER2 would fail with an error code if parsing failed. When moving it to async, we needed another way to handle that error and the solution employed was to set an error on the dma_fence and then trust that said error gets propagated to the client eventually. Moving back to synchronous will help us untangle the fence error propagation mess. This also reverts most of 0edbb9ba ("drm/i915: Move cmd parser pinning to execbuffer") which is a refactor of some of our allocation paths for asynchronous parsing. Now that everything is synchronous, we don't need it. v2 (Daniel Vetter): - Add stabel Cc and Fixes tag Signed-off-by: Jason Ekstrand <jason@jlekstrand.net> Cc: <stable@vger.kernel.org> # v5.6+ Fixes: 9e31c1fe ("drm/i915: Propagate errors on awaiting already signaled fences") Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> Reviewed-by: Jon Bloomfield <jon.bloomfield@intel.com> Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch> Link: https://patchwork.freedesktop.org/patch/msgid/20210714193419.1459723-2-jason@jlekstrand.net
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