diff --git a/sound/drivers/mpu401/mpu401.c b/sound/drivers/mpu401/mpu401.c
index c217c427bf1e..b93291ad067a 100644
--- a/sound/drivers/mpu401/mpu401.c
+++ b/sound/drivers/mpu401/mpu401.c
@@ -89,6 +89,12 @@ static int snd_mpu401_probe(struct platform_device *devptr)
 	int err;
 	struct snd_card *card;
 
+	if (dev < 0 || dev >= SNDRV_CARDS) {
+		dev_warn(&devptr->dev,
+			 "Invalid card index %d, using default 0\n", dev);
+		dev = 0;
+	}
+
 	if (port[dev] == SNDRV_AUTO_PORT) {
 		dev_err(&devptr->dev, "specify port\n");
 		return -EINVAL;