1 files changed, 34 insertions, 19 deletions

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index a9ea83ea321b..6faabf34f142 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -2854,11 +2854,9 @@ i915_gem_reset_prepare_engine(struct intel_engine_cs *engine)
 	if (engine->irq_seqno_barrier)
 		engine->irq_seqno_barrier(engine);
 
-	if (engine_stalled(engine)) {
-		request = i915_gem_find_active_request(engine);
-		if (request && request->fence.error == -EIO)
-			request = ERR_PTR(-EIO); /* Previous reset failed! */
-	}
+	request = i915_gem_find_active_request(engine);
+	if (request && request->fence.error == -EIO)
+		request = ERR_PTR(-EIO); /* Previous reset failed! */
 
 	return request;
 }
@@ -2927,12 +2925,11 @@ static void engine_skip_context(struct drm_i915_gem_request *request)
 	spin_unlock_irqrestore(&engine->timeline->lock, flags);
 }
 
-/* Returns true if the request was guilty of hang */
-static bool i915_gem_reset_request(struct drm_i915_gem_request *request)
+/* Returns the request if it was guilty of the hang */
+static struct drm_i915_gem_request *
+i915_gem_reset_request(struct intel_engine_cs *engine,
+		       struct drm_i915_gem_request *request)
 {
-	/* Read once and return the resolution */
-	const bool guilty = !i915_gem_request_completed(request);
-
 	/* The guilty request will get skipped on a hung engine.
 	 *
 	 * Users of client default contexts do not rely on logical
@@ -2954,15 +2951,34 @@ static bool i915_gem_reset_request(struct drm_i915_gem_request *request)
 	 * subsequent hangs.
 	 */
 
-	if (guilty) {
+	if (engine_stalled(engine)) {
 		i915_gem_context_mark_guilty(request->ctx);
 		skip_request(request);
+
+		/* If this context is now banned, skip all pending requests. */
+		if (i915_gem_context_is_banned(request->ctx))
+			engine_skip_context(request);
 	} else {
-		i915_gem_context_mark_innocent(request->ctx);
-		dma_fence_set_error(&request->fence, -EAGAIN);
+		/*
+		 * Since this is not the hung engine, it may have advanced
+		 * since the hang declaration. Double check by refinding
+		 * the active request at the time of the reset.
+		 */
+		request = i915_gem_find_active_request(engine);
+		if (request) {
+			i915_gem_context_mark_innocent(request->ctx);
+			dma_fence_set_error(&request->fence, -EAGAIN);
+
+			/* Rewind the engine to replay the incomplete rq */
+			spin_lock_irq(&engine->timeline->lock);
+			request = list_prev_entry(request, link);
+			if (&request->link == &engine->timeline->requests)
+				request = NULL;
+			spin_unlock_irq(&engine->timeline->lock);
+		}
 	}
 
-	return guilty;
+	return request;
 }
 
 void i915_gem_reset_engine(struct intel_engine_cs *engine,
@@ -2970,13 +2986,12 @@ void i915_gem_reset_engine(struct intel_engine_cs *engine,
 {
 	engine->irq_posted = 0;
 
-	if (request && i915_gem_reset_request(request)) {
+	if (request)
+		request = i915_gem_reset_request(engine, request);
+
+	if (request) {
 		DRM_DEBUG_DRIVER("resetting %s to restart from tail of request 0x%x\n",
 				 engine->name, request->global_seqno);
-
-		/* If this context is now banned, skip all pending requests. */
-		if (i915_gem_context_is_banned(request->ctx))
-			engine_skip_context(request);
 	}
 
 	/* Setup the CS to resume from the breadcrumb of the hung request */