mbim

[Aleksander Morgado]

Hey Mateusz,

For context for everyone, this email is in reply to this one:
https://lists.freedesktop.org/archives/modemmanager-devel/2020-December/008326.html

> [21:38][root at debian][~] $ mmcli -m 0
>     ------------------------------------
>     General  |                dbus path:
> /org/freedesktop/ModemManager1/Modem/0
>              |                device id:
> 195d53c7801757dda408ded11b37045665e5f6dc
>     ------------------------------------
>     Hardware |             manufacturer: Huawei Technologies Co., Ltd.
>              |                    model: HUAWEI Mobile V7R11
>              |        firmware revision: 11.617.15.00.00
>              |             h/w revision: RM1ME909ASM
>              |                supported: gsm-umts, lte
>              |                  current: gsm-umts, lte
>              |             equipment id: 867377029612433
>     ------------------------------------
>     System   |                   device:
> /sys/devices/pci0000:00/0000:00:14.0/usb3/3-7
>              |                  drivers: cdc_mbim
>              |                   plugin: huawei
>              |             primary port: cdc-wdm0
>              |                    ports: cdc-wdm0 (mbim), wwan0 (net)

So yes, the modem is being used in MBIM mode, and in the MBIM protocol
there is no "SMS store" operation:
https://gitlab.freedesktop.org/mobile-broadband/ModemManager/-/blob/master/src/mm-sms-mbim.c#L361

In the MBIM protocol there is not even a notion of "SMS storages";
ModemManager fakes the supported storages as "MT" only, but just to
give a value in the property, not because that storage can be actively
used:
https://gitlab.freedesktop.org/mobile-broadband/ModemManager/-/blob/master/src/mm-broadband-modem-mbim.c#L5327

Unfortunately, the modem doesn't even seem to have an AT port exposed,
so we cannot have a fallback operation based on the AT protocol for
the SMS store operations either.

-- 
Aleksander
https://aleksander.es