[Intel-gfx] [PATCH] drm/i915/gt: Update request status flags for debug pretty-printer

[Chris Wilson]

We plan to expand upon the number of available statuses for when we
pretty-print the requests along the timelines, and so need a new set of
flags. We have settled upon:

	Unready [U]
	  - initial status after being submitted, the request is not
	    ready for execution as it is waiting for external fences

	Ready [R]
	  - all fences the request was waiting on have been signaled,
            and the request is now ready for execution and will be
	    in a backend queue

	  - a ready request may still need to wait on semaphores
	    [internal fences]

	Ready/virtual [V]
	  - same as ready, but queued over multiple backends

	Executing [E]
	  - the request has been transferred from the backend queue and
	    submitted for execution on HW

	  - a completed request may still be regarded as executing, its
	    status may not be updated until it is retired and removed
	    from the lists

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
---
 drivers/gpu/drm/i915/gt/intel_lrc.c |  4 ++--
 drivers/gpu/drm/i915/i915_request.c | 30 +++++++++++++++++++++++++++++
 2 files changed, 32 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/gt/intel_lrc.c b/drivers/gpu/drm/i915/gt/intel_lrc.c
index b6ab1161942a..3a1b25c0e43e 100644
--- a/drivers/gpu/drm/i915/gt/intel_lrc.c
+++ b/drivers/gpu/drm/i915/gt/intel_lrc.c
@@ -6025,7 +6025,7 @@ void intel_execlists_show_requests(struct intel_engine_cs *engine,
 
 		priolist_for_each_request(rq, p, i) {
 			if (count++ < max - 1)
-				show_request(m, rq, "\t\tQ ");
+				show_request(m, rq, "\t\tR ");
 			else
 				last = rq;
 		}
@@ -6036,7 +6036,7 @@ void intel_execlists_show_requests(struct intel_engine_cs *engine,
 				   "\t\t...skipping %d queued requests...\n",
 				   count - max);
 		}
-		show_request(m, last, "\t\tQ ");
+		show_request(m, last, "\t\tR ");
 	}
 
 	last = NULL;
diff --git a/drivers/gpu/drm/i915/i915_request.c b/drivers/gpu/drm/i915/i915_request.c
index 673991718ae6..d3610418e9ae 100644
--- a/drivers/gpu/drm/i915/i915_request.c
+++ b/drivers/gpu/drm/i915/i915_request.c
@@ -1875,6 +1875,36 @@ void i915_request_show(struct drm_printer *m,
 	char buf[80] = "";
 	int x = 0;
 
+	/*
+	 * Often the prefix is used to show the queue status,
+	 * in which case we use the following flags:
+	 *
+	 *  Unready [U]
+	 *    - initial status upon being submitted by the user
+	 *
+	 *    - the request is not ready for execution as it is waiting
+	 *      for external fences
+	 *
+	 *  Ready [R]
+	 *    - all fences the request was waiting on have been signaled,
+	 *      and the request is now ready for execution and will be
+	 *      in a backend queue
+	 *
+	 *    - a ready request may still need to wait on semaphores
+	 *      [internal fences]
+	 *
+	 *  Ready/virtual [V]
+	 *    - same as ready, but queued over multiple backends
+	 *
+	 *  Executing [E]
+	 *    - the request has been transferred from the backend queue and
+	 *      submitted for execution on HW
+	 *
+	 *    - a completed request may still be regarded as executing, its
+	 *      status may not be updated until it is retired and removed
+	 *      from the lists
+	 */
+
 	x = print_sched_attr(&rq->sched.attr, buf, x, sizeof(buf));
 
 	drm_printf(m, "%s %llx:%lld%s%s %s @ %dms: %s\n",
-- 
2.20.1