[PATCH v6 3/4] drm/i915: Reset steer semaphore for media GT on resume

[Nirmoy Das]

During resume, the steer semaphore on GT1 was observed to be held. The
hardware team has confirmed the safety of clearing the steer semaphore
during driver load/resume, as no lock acquisitions can occur in this
process by other agents.

v2: reset on resume not in intel_gt_init().
v3: do the reset on intel_gt_resume_early()

Signed-off-by: Nirmoy Das <nirmoy.das at intel.com>
---
 drivers/gpu/drm/i915/gt/intel_gt_pm.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/drivers/gpu/drm/i915/gt/intel_gt_pm.c b/drivers/gpu/drm/i915/gt/intel_gt_pm.c
index dab73980c9f1..59cebf205b72 100644
--- a/drivers/gpu/drm/i915/gt/intel_gt_pm.c
+++ b/drivers/gpu/drm/i915/gt/intel_gt_pm.c
@@ -13,6 +13,7 @@
 #include "intel_engine_pm.h"
 #include "intel_gt.h"
 #include "intel_gt_clock_utils.h"
+#include "intel_gt_mcr.h"
 #include "intel_gt_pm.h"
 #include "intel_gt_print.h"
 #include "intel_gt_requests.h"
@@ -218,6 +219,17 @@ void intel_gt_pm_fini(struct intel_gt *gt)
 
 void intel_gt_resume_early(struct intel_gt *gt)
 {
+	/*
+	 * Reset the steer semaphore on GT1, as we have observed it
+	 * remaining held after a suspend operation. Confirmation
+	 * from the hardware team ensures the safety of resetting
+	 * the steer semaphore during driver load/resume, as there
+	 * are no lock acquisitions during this process by other
+	 * agents.
+	 */
+	if (MEDIA_VER(gt->i915) >= 13 && gt->type == GT_MEDIA)
+		intel_gt_mcr_lock_reset(gt);
+
 	intel_uncore_resume_early(gt->uncore);
 	intel_gt_check_and_clear_faults(gt);
 }
-- 
2.41.0