diff --git a/sys/dev/sound/pcm/sound.c b/sys/dev/sound/pcm/sound.c
--- a/sys/dev/sound/pcm/sound.c
+++ b/sys/dev/sound/pcm/sound.c
@@ -403,7 +403,7 @@
 		d->rvchancount++;
 		break;
 	default:
-		break;
+		__assert_unreachable();
 	}
 
 	return (0);
@@ -443,7 +443,7 @@
 		d->rvchancount--;
 		break;
 	default:
-		break;
+		__assert_unreachable();
 	}
 
 	return (0);