modemmanager/libmbim cannot make use of Quectel EM120

[Pirouette Cacahuète]

As reported on https://gitlab.freedesktop.org/mobile-broadband/ModemManager/-/issues/402, this modem (shipped in many new Lenovo ThinkPad laptops) requires some specific handling as others new modems to performs FCC unlock procedure.

A fix has been merged upstream: https://gitlab.freedesktop.org/mobile-broadband/libmbim/-/merge_requests/125/diffs

Can we expect to see that merged in the current Ubuntu 21.10 ?

I understand it might require a backport, since they merged it against 1.26 and it does not seems to apply cleanly on 1.24. I also suspect upgrading libmbim to 1.26 is not acceptable for impish release.

[Aleksander Morgado (aleksander-m)]

Please note the libmbim 1.24 branch is not actively maintained any more in upstream. If you want to keep on using that release, you're fully on your own.

[Pirouette Cacahuète (lissyx)]

I just had a look and next version of Ubuntu uses ModemMamager 1.18.2 as of now, so it does not have the handling for FCC unlock procedure.

[Yuan-Chen Cheng (ycheng-twn)]

For Today, the version of MondemManager in jammy 1.18.6

[Pirouette Cacahuète (lissyx)]

That would mean that Jammy, a LTS, will not be able to make use of LTE modems on 2021 shipped ThinkPad ?

[Sebastien Bacher (seb128)]

The new versions are in the current Ubuntu series, there is no plan to backport to impish though since that's a non LTS serie and there is limited demand for a such change

[Pirouette Cacahuète (lissyx)]

Thanks, I just saw that Jammy has 1.26.2. I might try and give it a try to verify the behavior of the LTE modem there.

[Pirouette Cacahuète (lissyx)]

I gave a try and I can confirm that following the modemmanager docs to enable FCC unlock procedure at ModemManager level, the modem is properly unlocked and connects to the internet.

However, this is another issue, but the firmware crashing persist when trying to make use of the LTE connection a bit more than just sending a ping.