drm/i915/guc: Add extra debug on CT deadlock

Print CT state (H2G + G2H head / tail pointers, credits) on CT
deadlock.

v2:
 (John Harrison)
  - Add units to debug messages
Reviewed-by: NJohn Harrison <John.C.Harrison@Intel.com>
Signed-off-by: NMatthew Brost <matthew.brost@intel.com>
Signed-off-by: NJohn Harrison <John.C.Harrison@Intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211214170500.28569-6-matthew.brost@intel.com

drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c

@@ -523,6 +523,15 @@ static inline bool ct_deadlocked(struct intel_guc_ct *ct)
 		CT_ERROR(ct, "Communication stalled for %lld ms, desc status=%#x,%#x\n",
 			 ktime_ms_delta(ktime_get(), ct->stall_time),
 			 send->status, recv->status);
+		CT_ERROR(ct, "H2G Space: %u (Bytes)\n",
+			 atomic_read(&ct->ctbs.send.space) * 4);
+		CT_ERROR(ct, "Head: %u (Dwords)\n", ct->ctbs.send.desc->head);
+		CT_ERROR(ct, "Tail: %u (Dwords)\n", ct->ctbs.send.desc->tail);
+		CT_ERROR(ct, "G2H Space: %u (Bytes)\n",
+			 atomic_read(&ct->ctbs.recv.space) * 4);
+		CT_ERROR(ct, "Head: %u\n (Dwords)", ct->ctbs.recv.desc->head);
+		CT_ERROR(ct, "Tail: %u\n (Dwords)", ct->ctbs.recv.desc->tail);
+
 		ct->ctbs.send.broken = true;
 	}