diff --git a/ddbridge/ddbridge-core.c b/ddbridge/ddbridge-core.c
index e790338..7d880ac 100644
--- a/ddbridge/ddbridge-core.c
+++ b/ddbridge/ddbridge-core.c
@@ -842,7 +842,8 @@ static int ts_open(struct inode *inode, struct file *file)
 	} else if ((file->f_flags & O_ACCMODE) == O_WRONLY) {
 		if (!output)
 			return -EINVAL;
-	}
+	} else
+		return -EINVAL;
 	err = dvb_generic_open(inode, file);
 	if (err < 0)
 		return err;