3.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: xiao jin <jin.x...@intel.com>
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.x...@intel.com>
Signed-off-by: Zhang, Qi1 <qi1.zh...@intel.com>
Reviewed-by: David Cohen <david.a.co...@linux.intel.com>
Signed-off-by: Johan Hovold <jhov...@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
drivers/usb/serial/usb_wwan.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
--- a/drivers/usb/serial/usb_wwan.c
+++ b/drivers/usb/serial/usb_wwan.c
@@ -236,8 +236,10 @@ int usb_wwan_write(struct tty_struct *tt
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);
--
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