From: xiao jin <jin.xiao@xxxxxxxxx> This patch has been added to the 3.12 stable tree. If you have any objections, please let us know. =============== commit db0904737947d509844e171c9863ecc5b4534005 upstream. When enable usb serial for modem data, sometimes the tty is blocked in tty_wait_until_sent because portdata->out_busy always is set and have no chance to be cleared. We find a bug in write error path. usb_wwan_write set portdata->out_busy firstly, then try autopm async with error. No out urb submit and no usb_wwan_outdat_callback to this write, portdata->out_busy can't be cleared. This patch clear portdata->out_busy if usb_wwan_write try autopm async with error. Fixes: 383cedc3bb43 ("USB: serial: full autosuspend support for the option driver") Signed-off-by: xiao jin <jin.xiao@xxxxxxxxx> Signed-off-by: Zhang, Qi1 <qi1.zhang@xxxxxxxxx> Reviewed-by: David Cohen <david.a.cohen@xxxxxxxxxxxxxxx> Signed-off-by: Johan Hovold <jhovold@xxxxxxxxx> Signed-off-by: Jiri Slaby <jslaby@xxxxxxx> --- drivers/usb/serial/usb_wwan.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/usb/serial/usb_wwan.c b/drivers/usb/serial/usb_wwan.c index 6fa78361be56..7096d0ba1d0f 100644 --- a/drivers/usb/serial/usb_wwan.c +++ b/drivers/usb/serial/usb_wwan.c @@ -228,8 +228,10 @@ int usb_wwan_write(struct tty_struct *tty, struct usb_serial_port *port, usb_pipeendpoint(this_urb->pipe), i); err = usb_autopm_get_interface_async(port->serial->interface); - if (err < 0) + if (err < 0) { + clear_bit(i, &portdata->out_busy); break; + } /* send the data */ memcpy(this_urb->transfer_buffer, buf, todo); -- 2.0.0 -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html