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@xxxxxxx>
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@xxxxxxxxxx>
Signed-off-by: Bjørn Mork <bjorn@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 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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