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path: root/drivers/gpu/drm/i915/gt/intel_ring_submission.c
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Diffstat (limited to 'drivers/gpu/drm/i915/gt/intel_ring_submission.c')
-rw-r--r--drivers/gpu/drm/i915/gt/intel_ring_submission.c8
1 files changed, 7 insertions, 1 deletions
diff --git a/drivers/gpu/drm/i915/gt/intel_ring_submission.c b/drivers/gpu/drm/i915/gt/intel_ring_submission.c
index 6e9977b2d180..a876a34455f1 100644
--- a/drivers/gpu/drm/i915/gt/intel_ring_submission.c
+++ b/drivers/gpu/drm/i915/gt/intel_ring_submission.c
@@ -365,7 +365,13 @@ static void reset_prepare(struct intel_engine_cs *engine)
ENGINE_READ_FW(engine, RING_HEAD),
ENGINE_READ_FW(engine, RING_TAIL),
ENGINE_READ_FW(engine, RING_START));
- if (!stop_ring(engine)) {
+ /*
+ * Sometimes engine head failed to set to zero even after writing into it.
+ * Use wait_for_atomic() with 20ms delay to let engine resumes from
+ * correct RING_HEAD. Experimented different values and determined
+ * that 20ms works best based on testing.
+ */
+ if (wait_for_atomic((!stop_ring(engine) == 0), 20)) {
drm_err(&engine->i915->drm,
"failed to set %s head to zero "
"ctl %08x head %08x tail %08x start %08x\n",