2 files changed, 24 insertions, 0 deletions

diff --git a/drivers/char/tty_port.c b/drivers/char/tty_port.c
index a4bbb28f10be..2e8552dc5eda 100644
--- a/drivers/char/tty_port.c
+++ b/drivers/char/tty_port.c
@@ -221,6 +221,9 @@ int tty_port_block_til_ready(struct tty_port *port,
            the port has just hung up or is in another error state */
         if ((filp->f_flags & O_NONBLOCK) ||
                         (tty->flags & (1 << TTY_IO_ERROR))) {
+                /* Indicate we are open */
+                if (tty->termios->c_cflag & CBAUD)
+                        tty_port_raise_dtr_rts(port);
                 port->flags |= ASYNC_NORMAL_ACTIVE;
                 return 0;
         }
diff --git a/drivers/usb/serial/cp210x.c b/drivers/usb/serial/cp210x.c
index 698252a4dc5d..bd254ec97d14 100644
--- a/drivers/usb/serial/cp210x.c
+++ b/drivers/usb/serial/cp210x.c
@@ -50,6 +50,8 @@ static int cp210x_tiocmset_port(struct usb_serial_port *port, struct file *,
 static void cp210x_break_ctl(struct tty_struct *, int);
 static int cp210x_startup(struct usb_serial *);
 static void cp210x_disconnect(struct usb_serial *);
+static void cp210x_dtr_rts(struct usb_serial_port *p, int on);
+static int cp210x_carrier_raised(struct usb_serial_port *p);
 
 static int debug;
 
@@ -143,6 +145,8 @@ static struct usb_serial_driver cp210x_device = {
         .tiocmset               = cp210x_tiocmset,
         .attach                 = cp210x_startup,
         .disconnect             = cp210x_disconnect,
+        .dtr_rts                = cp210x_dtr_rts,
+        .carrier_raised         = cp210x_carrier_raised
 };
 
 /* Config request types */
@@ -746,6 +750,14 @@ static int cp210x_tiocmset_port(struct usb_serial_port *port, struct file *file,
         return cp210x_set_config(port, CP210X_SET_MHS, &control, 2);
 }
 
+static void cp210x_dtr_rts(struct usb_serial_port *p, int on)
+{
+        if (on)
+                cp210x_tiocmset_port(p, NULL,  TIOCM_DTR|TIOCM_RTS, 0);
+        else
+                cp210x_tiocmset_port(p, NULL,  0, TIOCM_DTR|TIOCM_RTS);
+}
+
 static int cp210x_tiocmget (struct tty_struct *tty, struct file *file)
 {
         struct usb_serial_port *port = tty->driver_data;
@@ -768,6 +780,15 @@ static int cp210x_tiocmget (struct tty_struct *tty, struct file *file)
         return result;
 }
 
+static int cp210x_carrier_raised(struct usb_serial_port *p)
+{
+        unsigned int control;
+        cp210x_get_config(p, CP210X_GET_MDMSTS, &control, 1);
+        if (control & CONTROL_DCD)
+                return 1;
+        return 0;
+}
+
 static void cp210x_break_ctl (struct tty_struct *tty, int break_state)
 {
         struct usb_serial_port *port = tty->driver_data;