RFC: Workaround for newest QMI devices that require arguments in "WDA Get Data Format"

[Aleksander Morgado]

Hey all!

It looks like newest QMI devices will return a "Missing argument"
error to the "WDA Get Data Format" message (that originally takes no
mandatory or optional argument). This issue makes ModemManager fail to
detect the modem as a device requiring raw-ip, and it ends up in a
failed connection:
https://gitlab.freedesktop.org/mobile-broadband/ModemManager/issues/177#note_393168

This seems to apply to e.g. the Telit FN980m or the Quectel RM500Q.

I hacked up a patch in order to detect this specific error during the
QMI connection attempt, and if we see it, we'll fallback to say that
the device requires raw-ip right away:
https://gitlab.freedesktop.org/mobile-broadband/ModemManager/merge_requests/251

This seems to work, but of course, ideally we would better send the
"WDA Get Data Format" with the arguments it needs. Does anyone know
what is expected as argument in these new devices?

What do you all think about the hacky workaround?
Cheers!

-- 
Aleksander
https://aleksander.es