--- drivers/usb/serial/generic.c

+++ drivers/usb/serial/generic.c

@@ -578,6 +578,26 @@ int usb_serial_handle_break(struct usb_s

}

EXPORT_SYMBOL_GPL(usb_serial_handle_break);

+/**

+ * usb_serial_handle_dcd_change - handle a change of carrier detect state

+ * @port: usb_serial_port structure for the open port

+ * @tty: tty_struct structure for the port

+ * @status: new carrier detect status, nonzero if active

+ */

+void usb_serial_handle_dcd_change(struct usb_serial_port *usb_port,

+ struct tty_struct *tty, unsigned int status)

+{

+ struct tty_port *port = &usb_port->port;

+

+ dbg("%s - port %d, status %d", __func__, usb_port->number, status);

+

+ if (status)

+ wake_up_interruptible(&port->open_wait);

+ else if (tty && !C_CLOCAL(tty))

+ tty_hangup(tty);

+}

+EXPORT_SYMBOL_GPL(usb_serial_handle_dcd_change);

+

int usb_serial_generic_resume(struct usb_serial *serial)

{

struct usb_serial_port *port;