EM9190 randomly dial fail

[Aleksander Morgado]

Hey,

> When the issue happen, I checked system log and can see below error log related to cdc_mbim.ko. not sure whether this cause the issue.
>
> Apr 26 09:53:33  user.info kernel: [  169.732503] NETDEV WATCHDOG: wwan0 (cdc_mbim): transmit queue 0 timed out,trans_start:[4294932908,4294932908,4294932908],jiffies:4294934744,timeo:1250
> Apr 26 09:53:33  user.warn kernel: [  169.732543] ------------[ cut here ]------------

The "transmit queue 0 timed out" error indicates that the modem has
gone "silent" in the usb layer. The kernel driver doing networking
cannot communicate via USB to the device, and the reason for that is
usually an internal modem crash of some sort, a firmware issue. :/

But the errors you showed earlier are a bit orthogonal I believe; what
we saw was that the modem was returning an error about the MBIM
session being closed, and if that was returned, there was some USB
communication at that point.

We don't have full system logs mapping both issues, so cannot say much more.



-- 
Aleksander
https://aleksander.es