[PATCH] usb-serial: Fix usb serial console open/close regression

[Jason Wessel <jason.wessel@windriver.com>]

Commit e1108a63e10d344284011cccc06328b2cd3e5da3 ("usb_serial: Use the
shutdown() operation") breaks the ability to use a usb console
starting in 2.6.32.  This was observed when using
console=ttyUSB0,115200 as a boot argument with an FTDI device.  The
error is:

ftdi_sio ttyUSB0: ftdi_submit_read_urb - failed submitting read urb, error -22

The handling of the ASYNCB_INITIALIZED changed in 2.6.32 such that in
tty_port_shutdown() it always clears the flag if it is set.  As a work
around the usb console must reset this flag, in order for the hw to
stay open.

CC: Greg Kroah-Hartman <gregkh@suse.de>
CC: Alan Cox <alan@linux.intel.com>
CC: Alan Stern <stern@rowland.harvard.edu>
CC: Oliver Neukum <oliver@neukum.org>
CC: Andrew Morton <akpm@linux-foundation.org>
CC: linux-usb@vger.kernel.org
CC: linux-kernel@vger.kernel.org
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>

---
 drivers/usb/serial/usb-serial.c |    7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

--- a/drivers/usb/serial/usb-serial.c
+++ b/drivers/usb/serial/usb-serial.c
@@ -287,10 +287,13 @@ static void serial_down(struct tty_port 
 	struct usb_serial_driver *drv = port->serial->type;
 	/*
 	 * The console is magical.  Do not hang up the console hardware
-	 * or there will be tears.
+	 * or there will be tears.  If this is a console the initialized
+	 * flag is reset.
 	 */
-	if (port->console)
+	if (port->console) {
+		set_bit(ASYNCB_INITIALIZED, &port->port.flags);
 		return;
+	}
 	if (drv->close)
 		drv->close(port);
 }