[PATCH 5.19 17/38] drm/i915/guc: Cancel GuC engine busyness worker synchronously

Greg Kroah-Hartman
2022-09-21T15:51:02Z

From: Umesh Nerlige Ramappa <umesh.nerlige.ramappa@intel.com>

[ Upstream commit aee5ae7c8492eaca2be20d202887c9c716ffc86f ]

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.

v2: Fix author name and sign-off mismatch

Signed-off-by: Umesh Nerlige Ramappa <umesh.nerlige.ramappa@intel.com>
Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/4419
Fixes: 77cdd054dd2c ("drm/i915/pmu: Connect engine busyness stats from GuC to pmu")
Reviewed-by: Ashutosh Dixit <ashutosh.dixit@intel.com>
Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220827002135.139349-1-umesh.nerlige.ramappa@intel.com
Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
(cherry picked from commit 31335aa8e08be3fe10c50aecd2f11aba77544a78)
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
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 96022f49f9b5..d7e4681d7297 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.
--
2.35.1