1 files changed, 20 insertions, 0 deletions

diff --git a/drivers/usb/serial/generic.c b/drivers/usb/serial/generic.c
index e6833e216fc9..e4db5ad2bc55 100644
--- a/drivers/usb/serial/generic.c
+++ b/drivers/usb/serial/generic.c
@@ -479,6 +479,26 @@ int usb_serial_handle_break(struct usb_serial_port *port)
 }
 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;