[PATCH 1/5] tty_port,usb-console: Fix usb serial console open/close regression

From: Jason Wessel
Date: Tue Mar 16 2010 - 17:06:43 EST


Commit e1108a63e10d344284011cccc06328b2cd3e5da3 ("usb_serial: Use the
shutdown() operation") breaks the ability to use a usb console
starting in 2.6.33. 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. The fix
is to add a variable to the tty_port struct to indicate when the tty
port is a console.

CC: Greg Kroah-Hartman <gregkh@xxxxxxx>
CC: Alan Cox <alan@xxxxxxxxxxxxxxx>
CC: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
CC: Oliver Neukum <oliver@xxxxxxxxxx>
CC: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
CC: linux-usb@xxxxxxxxxxxxxxx
Signed-off-by: Jason Wessel <jason.wessel@xxxxxxxxxxxxx>
---
drivers/char/tty_port.c | 2 +-
drivers/usb/serial/console.c | 1 +
include/linux/tty.h | 1 +
3 files changed, 3 insertions(+), 1 deletions(-)

diff --git a/drivers/char/tty_port.c b/drivers/char/tty_port.c
index be492dd..a3bd1d0 100644
--- a/drivers/char/tty_port.c
+++ b/drivers/char/tty_port.c
@@ -119,7 +119,7 @@ EXPORT_SYMBOL(tty_port_tty_set);
static void tty_port_shutdown(struct tty_port *port)
{
mutex_lock(&port->mutex);
- if (port->ops->shutdown &&
+ if (port->ops->shutdown && !port->console &&
test_and_clear_bit(ASYNCB_INITIALIZED, &port->flags))
port->ops->shutdown(port);
mutex_unlock(&port->mutex);
diff --git a/drivers/usb/serial/console.c b/drivers/usb/serial/console.c
index b22ac32..f347da2 100644
--- a/drivers/usb/serial/console.c
+++ b/drivers/usb/serial/console.c
@@ -181,6 +181,7 @@ static int usb_console_setup(struct console *co, char *options)
/* The console is special in terms of closing the device so
* indicate this port is now acting as a system console. */
port->console = 1;
+ port->port.console = 1;

mutex_unlock(&serial->disc_mutex);
return retval;
diff --git a/include/linux/tty.h b/include/linux/tty.h
index 568369a..9c9719e 100644
--- a/include/linux/tty.h
+++ b/include/linux/tty.h
@@ -223,6 +223,7 @@ struct tty_port {
wait_queue_head_t close_wait; /* Close waiters */
wait_queue_head_t delta_msr_wait; /* Modem status change */
unsigned long flags; /* TTY flags ASY_*/
+ unsigned char console:1; /* port is a console */
struct mutex mutex; /* Locking */
struct mutex buf_mutex; /* Buffer alloc lock */
unsigned char *xmit_buf; /* Optional buffer */
--
1.6.4.rc1

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