diff --git a/drivers/isdn/capi/capi.c b/drivers/isdn/capi/capi.c
index 871b0cbca5e..798d7f3e42e 100644
--- a/drivers/isdn/capi/capi.c
+++ b/drivers/isdn/capi/capi.c
@@ -1231,7 +1231,7 @@ static int capinc_tty_ioctl(struct tty_struct *tty, struct file * file,
 	int error = 0;
 	switch (cmd) {
 	default:
-		error = n_tty_ioctl (tty, file, cmd, arg);
+		error = n_tty_ioctl_helper(tty, file, cmd, arg);
 		break;
 	}
 	return error;
diff --git a/drivers/isdn/gigaset/ser-gigaset.c b/drivers/isdn/gigaset/ser-gigaset.c
index 5e89fa17781..cc4f4e44ffe 100644
--- a/drivers/isdn/gigaset/ser-gigaset.c
+++ b/drivers/isdn/gigaset/ser-gigaset.c
@@ -645,7 +645,7 @@ gigaset_tty_ioctl(struct tty_struct *tty, struct file *file,
 	case TCGETS:
 	case TCGETA:
 		/* pass through to underlying serial device */
-		rc = n_tty_ioctl(tty, file, cmd, arg);
+		rc = n_tty_ioctl_helper(tty, file, cmd, arg);
 		break;
 
 	case TCFLSH:
@@ -660,7 +660,7 @@ gigaset_tty_ioctl(struct tty_struct *tty, struct file *file,
 			break;
 		}
 		/* flush the serial port's buffer */
-		rc = n_tty_ioctl(tty, file, cmd, arg);
+		rc = n_tty_ioctl_helper(tty, file, cmd, arg);
 		break;
 
 	case FIONREAD: