could not grab port cdc-wdm0: Cannot add port 'usbmisc/cdc-wdm0', unhandled port

[Aleksander Morgado]

Hey Juan

> I have a system with MM 1.16.4 (NM 1.20.4) and I'm facing some
> problems with my SIMCOM SIM7600G-H
>
> In some systems, I get a successful activation of the cdc-wdm0 device
> and the wwan0 interface comes up and in some other systems, cdc-wdm0
> fails to be grabbed/activated and the wwan0 stays down.
>
> I'm attaching the success and failure logs.
>
> Any clues on where the issue might lie, or where to look for more
> info, would be really appreciated.
>

The MM version you're using has a 25s timeout when checking for the
QMI support, which may not be enough for newer devices, which take a
looong time to respond in the QMI port.

You may just need this patch
https://gitlab.freedesktop.org/mobile-broadband/ModemManager/-/commit/b7f0f2ca7c6e61fcf08786909ba0992d0de36ce6
which was released with MM 1.16.6.

-- 
Aleksander
https://aleksander.es