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  1. Jul 14, 2021
  2. Jul 11, 2021
    • Ville Syrjälä's avatar
      drm/i915/gt: Fix -EDEADLK handling regression · 78d2ad7e
      Ville Syrjälä authored
      The conversion to ww mutexes failed to address the fence code which
      already returns -EDEADLK when we run out of fences. Ww mutexes on
      the other hand treat -EDEADLK as an internal errno value indicating
      a need to restart the operation due to a deadlock. So now when the
      fence code returns -EDEADLK the higher level code erroneously
      restarts everything instead of returning the error to userspace
      as is expected.
      
      To remedy this let's switch the fence code to use a different errno
      value for this. -ENOBUFS seems like a semi-reasonable unique choice.
      Apart from igt the only user of this I could find is sna, and even
      there all we do is dump the current fence registers from debugfs
      into the X server log. So no user visible functionality is affected.
      If we really cared about preserving this we could of course convert
      back to -EDEADLK higher up, but doesn't seem like that's worth
      the hassle here.
      
      Not quite sure which commit specifically broke this, but I'll
      just attribute it to the general gem ww mutex work.
      
      Cc: stable@vger.kernel.org
      Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
      Cc: Thomas Hellström <thomas.hellstrom@intel.com>
      Testcase: igt/gem_pread/exhaustion
      Testcase: igt/gem_pwrite/basic-exhaustion
      Testcase: igt/gem_fenced_exec_thrash/too-many-fences
      Fixes: 80f0b679
      
       ("drm/i915: Add an implementation for i915_gem_ww_ctx locking, v2.")
      Signed-off-by: default avatarVille Syrjälä <ville.syrjala@linux.intel.com>
      Link: https://patchwork.freedesktop.org/patch/msgid/20210630164413.25481-1-ville.syrjala@linux.intel.com
      
      
      Reviewed-by: default avatarMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
      78d2ad7e
  3. Jul 09, 2021
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