* available in the work queue (note, the queue is shared,
* not per-engine). It is OK for this to be nonzero, but
* it should not be huge!
- * q_fail: failed to enqueue a work item. This should never happen,
- * because we check for space beforehand.
* b_fail: failed to ring the doorbell. This should never happen, unless
* somehow the hardware misbehaves, or maybe if the GuC firmware
* crashes? We probably need to reset the GPU to recover.