[Intel-gfx] [PATCH] drm/i915/guc: Cancel GuC engine busyness worker synchronously

Nerlige Ramappa, Umesh
2022-07-26T20:51:29Z

The worker is canceled in gt_park path, but earlier it was assumed that
gt_park path cannot sleep and the cancel is asynchronous. This caused a
race with suspend flow where the worker runs after suspend and causes an
unclaimed register access warning. Cancel the worker synchronously since
the gt_park is indeed allowed to sleep.

Signed-off-by: Umesh Nerlige Ramappa <umesh.nerlige.ramappa@intel.com>
Fixes: 77cdd054dd2c ("drm/i915/pmu: Connect engine busyness stats from GuC to pmu")
---
drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)

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 76916aed897a..0b7a5ecb640a 100644
--- a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
+++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
@@ -1438,7 +1438,12 @@ void intel_guc_busyness_park(struct intel_gt *gt)
if (!guc_submission_initialized(guc))
return;

- cancel_delayed_work(&guc->timestamp.work);
+ /*
+ * There is a race with suspend flow where the worker runs after suspend
+ * and causes an unclaimed register access warning. Cancel the worker
+ * synchronously here.
+ */
+ cancel_delayed_work_sync(&guc->timestamp.work);

/*
* Before parking, we should sample engine busyness stats if we need to.
--
2.36.1