[RFC PATCH] drm/i915/gt: Do not treat MCR locking timeouts as errors

Andi Shyti andi.shyti at linux.intel.com
Wed Oct 4 09:43:57 UTC 2023


The MCR steering semaphore is a shared lock entry between i915
and various firmware components.

Getting the lock might sinchronize on some shared resources.
Sometimes though, it might happen that the firmware forgets to
unlock causing unnecessary noise in the driver which keeps doing
what was supposed to do, ignoring the problem.

Do not consider this failure as an error, but just print a debug
message stating that the MCR locking has been skipped.

On the driver side we still have spinlocks that make sure that
the access to the resources is serialized.

Signed-off-by: Andi Shyti <andi.shyti at linux.intel.com>
Cc: Jonathan Cavitt <jonathan.cavitt at intel.com>
Cc: Matt Roper <matthew.d.roper at intel.com>
Cc: Nirmoy Das <nirmoy.das at intel.com>
---
 drivers/gpu/drm/i915/gt/intel_gt_mcr.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/i915/gt/intel_gt_mcr.c b/drivers/gpu/drm/i915/gt/intel_gt_mcr.c
index 326c2ed1d99b..51eb693df39b 100644
--- a/drivers/gpu/drm/i915/gt/intel_gt_mcr.c
+++ b/drivers/gpu/drm/i915/gt/intel_gt_mcr.c
@@ -395,10 +395,8 @@ void intel_gt_mcr_lock(struct intel_gt *gt, unsigned long *flags)
 	 * would indicate some hardware/firmware is misbehaving and not
 	 * releasing it properly.
 	 */
-	if (err == -ETIMEDOUT) {
-		gt_err_ratelimited(gt, "hardware MCR steering semaphore timed out");
-		add_taint_for_CI(gt->i915, TAINT_WARN);  /* CI is now unreliable */
-	}
+	if (err == -ETIMEDOUT)
+		gt_dbg(gt, "hardware MCR steering semaphore timed out");
 }
 
 /**
-- 
2.40.1



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