Messages in this thread Patch in this message | | | Date | Fri, 15 Feb 2013 17:23:59 +0900 | From | Alex Courbot <> | Subject | Re: usb_wwan_write() called while device still being resumed |
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Hi Bjørn, thanks for the reply!
On 02/15/2013 02:41 AM, Bjørn Mork wrote: > I believe the usb_autopm_get_interface_async() failing is OK in this > case, but that should not cause the modem to stop working. > > Wonder if this patch solves the problem? : > > From: =?UTF-8?q?Bj=C3=B8rn=20Mork?= <bjorn@mork.no> > Date: Thu, 14 Feb 2013 18:34:48 +0100 > Subject: [PATCH] USB: usb_wwan: clear port busy state on error > MIME-Version: 1.0 > Content-Type: text/plain; charset=UTF-8 > Content-Transfer-Encoding: 8bit > > Reported-by: Alex Courbot <acourbot@nvidia.com> > Signed-off-by: Bjørn Mork <bjorn@mork.no> > --- > 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 01c94aa..44e106d 100644 > --- a/drivers/usb/serial/usb_wwan.c > +++ b/drivers/usb/serial/usb_wwan.c > @@ -230,8 +230,10 @@ 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); >
Unfortunately it does not, and fails the same way. On the other hand, I do not see the issue when doing the following:
diff --git a/drivers/usb/serial/usb_wwan.c b/drivers/usb/serial/usb_wwan.c index e4fad5e..1490029 100644 --- a/drivers/usb/serial/usb_wwan.c +++ b/drivers/usb/serial/usb_wwan.c @@ -238,8 +238,6 @@ 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) - break;
/* send the data */ memcpy(this_urb->transfer_buffer, buf, todo); After doing this I don't see this issue anymore. It looks wrong though. But it seems to work despite the obvious unbalance in autopm calls that results.
If I understand you correctly, usb_wwan_write() failing here is not a problem in itself, and the ack should just be sent again later?
> that should not cause the modem to stop working.
Actually it might also be that the network stack ends up in a bad state and remains stuck in it. I don't think the modem by itself is affected. All I observe is that no network traffic takes place after this. I'm not familiar enough with networking to make any stronger assumption.
FWIW, when usb_autopm_get_interface_async() returns -EACCES, the power parameters of port->serial->interface->dev are as follows:
disable_depth = 1 is_suspended = 1 runtime_status = 2 (RPM_SUSPENDED)
Thanks, Alex.
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