diff --git a/ch34x.c b/ch34x.c
index dd08001..b640a73 100644
--- a/ch34x.c
+++ b/ch34x.c
@@ -399,7 +399,7 @@ static int ch34x_get_baud_rate( unsigned int baud_rate,
 
 #if (LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,27))
 static void ch34x_set_termios( struct tty_struct *tty,
-		struct usb_serial_port *port, struct ktermios *old_termios )
+		struct usb_serial_port *port, const struct ktermios *old_termios )
 {
 #else
 static void ch34x_set_termios( struct usb_serial_port *port,