--- include/linux/usb/serial.h

+++ include/linux/usb/serial.h

@@ -326,6 +326,9 @@ extern int usb_serial_handle_sysrq_char(

struct usb_serial_port *port,

unsigned int ch);

extern int usb_serial_handle_break(struct usb_serial_port *port);

+extern void usb_serial_handle_dcd_change(struct usb_serial_port *usb_port,

+ struct tty_struct *tty,

+ unsigned int status);

extern int usb_serial_bus_register(struct usb_serial_driver *device);