[Intel-gfx] [PATCH] i915/guc: Run busyness worker only if gt is awake

[Umesh Nerlige Ramappa]

The worker is canceled in the __gt_park path, but we still see it
running sometimes during suspend. This is likely because some code is
getting a gt wakeref in the __gt_park path.

Only update stats if gt is awake. If not, intel_guc_busyness_park would
have already updated the stats. Note that we do not requeue the worker
if gt is not awake since intel_guc_busyness_unpark would do that at some
point.

If the gt was parked longer than time taken for GT timestamp to roll
over, we ignore those rollovers since we don't care about tracking the
exact GT time. We only care about roll overs when the gt is active and
running workloads.

Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/7077
Signed-off-by: Umesh Nerlige Ramappa <umesh.nerlige.ramappa at intel.com>
---
 .../gpu/drm/i915/gt/uc/intel_guc_submission.c | 27 ++++++++++++++++---
 1 file changed, 23 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
index e250bedf90fb..df31d6047ce9 100644
--- a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
+++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
@@ -1457,10 +1457,27 @@ static void guc_timestamp_ping(struct work_struct *wrk)
 	struct intel_uc *uc = container_of(guc, typeof(*uc), guc);
 	struct intel_gt *gt = guc_to_gt(guc);
 	struct intel_context *ce;
-	intel_wakeref_t wakeref;
 	unsigned long index;
 	int srcu, ret;
 
+	/*
+	 * The worker is canceled in the __gt_park path, but we still see it
+	 * running sometimes during suspend. This is likely because some code
+	 * is getting a gt wakeref in the __gt_park path.
+	 *
+	 * Only update stats if gt is awake. If not, intel_guc_busyness_park
+	 * would have already updated the stats. Note that we do not requeue the
+	 * worker in this case since intel_guc_busyness_unpark would do that at
+	 * some point.
+	 *
+	 * If the gt was parked longer than time taken for GT timestamp to roll
+	 * over, we ignore those rollovers since we don't care about tracking
+	 * the exact GT time. We only care about roll overs when the gt is
+	 * active and running workloads.
+	 */
+	if (!intel_gt_pm_get_if_awake(gt))
+		return;
+
 	/*
 	 * Synchronize with gt reset to make sure the worker does not
 	 * corrupt the engine/guc stats. NB: can't actually block waiting
@@ -1468,17 +1485,19 @@ static void guc_timestamp_ping(struct work_struct *wrk)
 	 * this worker thread if started. So waiting would deadlock.
 	 */
 	ret = intel_gt_reset_trylock(gt, &srcu);
-	if (ret)
+	if (ret) {
+		intel_gt_pm_put(gt);
 		return;
+	}
 
-	with_intel_runtime_pm(&gt->i915->runtime_pm, wakeref)
-		__update_guc_busyness_stats(guc);
+	__update_guc_busyness_stats(guc);
 
 	/* adjust context stats for overflow */
 	xa_for_each(&guc->context_lookup, index, ce)
 		guc_context_update_stats(ce);
 
 	intel_gt_reset_unlock(gt, srcu);
+	intel_gt_pm_put(gt);
 
 	guc_enable_busyness_worker(guc);
 }
-- 
2.38.1