drm/i915/guc: Remove failed doorbell stat from debugfs

This stat is almost always zero unless fatal error occurs,
which should be reported by other means anyway.

Suggested-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170518113104.54400-2-michal.wajdeczko@intel.com
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

drivers/gpu/drm/i915/i915_debugfs.c

@@ -2482,7 +2482,6 @@ static void i915_guc_client_info(struct seq_file *m,
 		client->wq_size, client->wq_offset, client->wq_tail);
 
 	seq_printf(m, "\tWork queue full: %u\n", client->no_wq_space);
-	seq_printf(m, "\tFailed doorbell: %u\n", client->b_fail);
 	seq_printf(m, "\tLast submission result: %d\n", client->retcode);
 
 	for_each_engine(engine, dev_priv, id) {

drivers/gpu/drm/i915/i915_guc_submission.c

@@ -615,8 +615,6 @@ static void __i915_guc_submit(struct drm_i915_gem_request *rq)
 
 	client->submissions[engine_id] += 1;
 	client->retcode = b_ret;
-	if (b_ret)
-		client->b_fail += 1;
 
 	guc->submissions[engine_id] += 1;
 	guc->last_seqno[engine_id] = rq->global_seqno;

drivers/gpu/drm/i915/intel_uc.h

@@ -59,9 +59,6 @@ struct drm_i915_gem_request;
  *                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!
- *   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.
  *   retcode: errno from last guc_submit()
  */
 struct i915_guc_client {
@@ -85,7 +82,6 @@ struct i915_guc_client {
 	uint32_t wq_tail;
 	uint32_t wq_rsvd;
 	uint32_t no_wq_space;
-	uint32_t b_fail;
 	int retcode;
 
 	/* Per-engine counts of GuC submissions */