diff --git a/include/linux/tty.h b/include/linux/tty.h
index c555f54..defd2ab 100644
--- a/include/linux/tty.h
+++ b/include/linux/tty.h
@@ -319,6 +319,7 @@
 extern void tty_termios_encode_baud_rate(struct ktermios *termios, speed_t ibaud, speed_t obaud);
 extern void tty_encode_baud_rate(struct tty_struct *tty, speed_t ibaud, speed_t obaud);
 extern void tty_termios_copy_hw(struct ktermios *new, struct ktermios *old);
+extern int tty_termios_hw_change(struct ktermios *a, struct ktermios *b);
 
 extern struct tty_ldisc *tty_ldisc_ref(struct tty_struct *);
 extern void tty_ldisc_deref(struct tty_ldisc *);