[PATCH 17/27] drm/i915/guc: Flush G2H work queue during reset

[Matthew Brost]

It isn't safe to scrub for missing G2H or continue with the reset until
all G2H processing is complete. Flush the G2H work queue during reset to
ensure it is done running. No need to call the IRQ handler directly
either as the scrubbing code can deal with any missing G2H.

Fixes: eb5e7da736f3 ("drm/i915/guc: Reset implementation for new GuC interface")
Signed-off-by: Matthew Brost <matthew.brost at intel.com>
Reviewed-by: Daniele Ceraolo Spurio <daniele.ceraolospurio at intel.com>
---
 .../gpu/drm/i915/gt/uc/intel_guc_submission.c  | 18 ++----------------
 1 file changed, 2 insertions(+), 16 deletions(-)

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 2949dce57489..baf789f37d42 100644
--- a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
+++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
@@ -714,8 +714,6 @@ static void guc_flush_submissions(struct intel_guc *guc)
 
 void intel_guc_submission_reset_prepare(struct intel_guc *guc)
 {
-	int i;
-
 	if (unlikely(!guc_submission_initialized(guc))) {
 		/* Reset called during driver load? GuC not yet initialised! */
 		return;
@@ -731,20 +729,8 @@ void intel_guc_submission_reset_prepare(struct intel_guc *guc)
 
 	guc_flush_submissions(guc);
 
-	/*
-	 * Handle any outstanding G2Hs before reset. Call IRQ handler directly
-	 * each pass as interrupt have been disabled. We always scrub for
-	 * outstanding G2H as it is possible for outstanding_submission_g2h to
-	 * be incremented after the context state update.
-	 */
-	for (i = 0; i < 4 && atomic_read(&guc->outstanding_submission_g2h); ++i) {
-		intel_guc_to_host_event_handler(guc);
-#define wait_for_reset(guc, wait_var) \
-		intel_guc_wait_for_pending_msg(guc, wait_var, false, (HZ / 20))
-		do {
-			wait_for_reset(guc, &guc->outstanding_submission_g2h);
-		} while (!list_empty(&guc->ct.requests.incoming));
-	}
+	flush_work(&guc->ct.requests.worker);
+
 	scrub_guc_desc_for_outstanding_g2h(guc);
 }
 
-- 
2.32.0