1 files changed, 57 insertions, 0 deletions
diff --git a/drivers/gpu/drm/i915/intel_guc.c b/drivers/gpu/drm/i915/intel_guc.c
index 92ed22f38fc4..3c6bf5a34c3c 100644
--- a/drivers/gpu/drm/i915/intel_guc.c
+++ b/drivers/gpu/drm/i915/intel_guc.c
@@ -69,6 +69,63 @@ void intel_guc_init_early(struct intel_guc *guc)
 	guc->notify = gen8_guc_raise_irq;
 }
 
+int intel_guc_init_wq(struct intel_guc *guc)
+{
+	struct drm_i915_private *dev_priv = guc_to_i915(guc);
+
+	/*
+	 * GuC log buffer flush work item has to do register access to
+	 * send the ack to GuC and this work item, if not synced before
+	 * suspend, can potentially get executed after the GFX device is
+	 * suspended.
+	 * By marking the WQ as freezable, we don't have to bother about
+	 * flushing of this work item from the suspend hooks, the pending
+	 * work item if any will be either executed before the suspend
+	 * or scheduled later on resume. This way the handling of work
+	 * item can be kept same between system suspend & rpm suspend.
+	 */
+	guc->log.runtime.flush_wq = alloc_ordered_workqueue("i915-guc_log",
+						WQ_HIGHPRI | WQ_FREEZABLE);
+	if (!guc->log.runtime.flush_wq)
+		return -ENOMEM;
+
+	/*
+	 * Even though both sending GuC action, and adding a new workitem to
+	 * GuC workqueue are serialized (each with its own locking), since
+	 * we're using mutliple engines, it's possible that we're going to
+	 * issue a preempt request with two (or more - each for different
+	 * engine) workitems in GuC queue. In this situation, GuC may submit
+	 * all of them, which will make us very confused.
+	 * Our preemption contexts may even already be complete - before we
+	 * even had the chance to sent the preempt action to GuC!. Rather
+	 * than introducing yet another lock, we can just use ordered workqueue
+	 * to make sure we're always sending a single preemption request with a
+	 * single workitem.
+	 */
+	if (HAS_LOGICAL_RING_PREEMPTION(dev_priv) &&
+	    USES_GUC_SUBMISSION(dev_priv)) {
+		guc->preempt_wq = alloc_ordered_workqueue("i915-guc_preempt",
+							  WQ_HIGHPRI);
+		if (!guc->preempt_wq) {
+			destroy_workqueue(guc->log.runtime.flush_wq);
+			return -ENOMEM;
+		}
+	}
+
+	return 0;
+}
+
+void intel_guc_fini_wq(struct intel_guc *guc)
+{
+	struct drm_i915_private *dev_priv = guc_to_i915(guc);
+
+	if (HAS_LOGICAL_RING_PREEMPTION(dev_priv) &&
+	    USES_GUC_SUBMISSION(dev_priv))
+		destroy_workqueue(guc->preempt_wq);
+
+	destroy_workqueue(guc->log.runtime.flush_wq);
+}
+
 static int guc_shared_data_create(struct intel_guc *guc)
 {
 	struct i915_vma *vma;