[PATCH v2 1/1] drm/i915/gt: Increase a time to retry RING_HEAD reset

[Nitin Gote]

Issue seen again where engine resets fails because the engine resumes from
an incorrect RING_HEAD. HEAD is still not 0 even after writing into it.
This seems to be timing issue and we experimented different values from 5ms
to 50ms and found out that 50ms works best based on testing.
So, if write doesn't succeed at first then retry again.

Closes: https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/12806
Signed-off-by: Nitin Gote <nitin.r.gote at intel.com>
---
 drivers/gpu/drm/i915/gt/intel_ring_submission.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/gt/intel_ring_submission.c b/drivers/gpu/drm/i915/gt/intel_ring_submission.c
index 32f3b52a183a..bc9f28524713 100644
--- a/drivers/gpu/drm/i915/gt/intel_ring_submission.c
+++ b/drivers/gpu/drm/i915/gt/intel_ring_submission.c
@@ -231,7 +231,7 @@ static int xcs_resume(struct intel_engine_cs *engine)
 	set_pp_dir(engine);
 
 	/* First wake the ring up to an empty/idle ring */
-	for ((kt) = ktime_get() + (2 * NSEC_PER_MSEC);
+	for ((kt) = ktime_get() + (50 * NSEC_PER_MSEC);
 			ktime_before(ktime_get(), (kt)); cpu_relax()) {
 		/*
 		 * In case of resets fails because engine resumes from
-- 
2.25.1