diff --git a/sound/hda/hdac_stream.c b/sound/hda/hdac_stream.c
index 1b8be39c38a9..741a5d17ae4c 100644
--- a/sound/hda/hdac_stream.c
+++ b/sound/hda/hdac_stream.c
@@ -338,8 +338,10 @@ struct hdac_stream *snd_hdac_stream_assign(struct hdac_bus *bus,
 	struct hdac_stream *res = NULL;
 
 	/* make a non-zero unique key for the substream */
-	int key = (substream->pcm->device << 16) | (substream->number << 2) |
-		(substream->stream + 1);
+	int key = (substream->number << 2) | (substream->stream + 1);
+
+	if (substream->pcm)
+		key |= (substream->pcm->device << 16);
 
 	spin_lock_irq(&bus->reg_lock);
 	list_for_each_entry(azx_dev, &bus->stream_list, list) {