tty_port: Move hupcl handling

Move the HUCPL handling from the end of close_port_start to the beginning
of close_port_end. What this actually does is change the ordering from

	port shutdown
	port->dtr_rts

to

	port->dtr_rts
	port shutdown

Some hardware drops the physical connection on shutdown so we must perform
the port operations before the shutdown.

Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 8 insertions, 5 deletions

diff --git a/drivers/char/tty_port.c b/drivers/char/tty_port.c
index 41b314cfda47..dd471d63fae2 100644
--- a/drivers/char/tty_port.c
+++ b/drivers/char/tty_port.c
@@ -339,6 +339,14 @@ int tty_port_close_start(struct tty_port *port,
                         timeout = 2 * HZ;
                 schedule_timeout_interruptible(timeout);
         }
+        /* Flush the ldisc buffering */
+        tty_ldisc_flush(tty);
+
+        /* Drop DTR/RTS if HUPCL is set. This causes any attached modem to
+           hang up the line */
+        if (tty->termios->c_cflag & HUPCL)
+                tty_port_lower_dtr_rts(port);
+
         /* Don't call port->drop for the last reference. Callers will want
            to drop the last active reference in ->shutdown() or the tty
            shutdown path */
@@ -350,11 +358,6 @@ void tty_port_close_end(struct tty_port *port, struct tty_struct *tty)
 {
         unsigned long flags;
 
-        tty_ldisc_flush(tty);
-
-        if (tty->termios->c_cflag & HUPCL)
-                tty_port_lower_dtr_rts(port);
-
         spin_lock_irqsave(&port->lock, flags);
         tty->closing = 0;