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

[Reinhard Speyerer]

On Mon, Jan 27, 2020 at 09:44:35AM +0100, Aleksander Morgado wrote:
> 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?
> 

Hi Aleksander,

perhaps these devices now need an "Endpoint Info" TLV for "WDA Get Data Format"
too similar to what is used with "WDA Set Data Format" and QMAP MUXing?

For the Quectel RM500Q you could also ask for clarification here
https://forums.quectel.com/c/iot-module/5g-module .

Regards,
Reinhard