SMS support through MBIM

[Aleksander Morgado]

Hey,

I spent some time working in SMS support for MBIM modems in
ModemManager. I got two branches working now:
 * 'aleksander/sms' branch in libmbim
 * 'aleksander/mbim-sms' branch in ModemManager

There doesn't seem to be a way in MBIM to configure which SMS storages
to use; the modem should handle a 'virtual' storage so that the user
does not need to worry about. Also, there doesn't seem to be a way of
storing new SMS messages without sending them, so Store() is useless.

But then, my Huawei MBIM device has the following specific issues:

 * The modem doesn't use SMS_READ notifications to notify about new
messages. Instead, a new 'SMS_MESSAGE_STORE_STATUS' indication is sent,
which I thought should only be used for flash non-class 0 messages.

 * My Huawei modem doesn't store these newly received messages, so when
MM is rebooted no SMS messages are found when listing them.

 * On a related note, telling the modem which notifications are enabled
or disabled with DEVICE_SERVICE_SUBSCRIBER_LIST doesn't seem to have any
effect. Even if I disable all notifications of a given service, they
don't seem to get really disabled in the modem (e.g. the signal info one).

Can any of you check how other MBIM devices behave?

Relevant mmcli commands would be:

 * Send SMS with:
 $> mmcli -m 0 --messaging-create-sms="number=1234,text=something"
 Successfully created new SMS:
	/org/freedesktop/ModemManager1/SMS/0 (unknown)

 $> mmcli -s 0 --send
 successfully sent the SMS

And when receiving a new message, check the logs and look for a
"Received flash message" log... or just send back the full log and I'll
look at it.

Cheers!

-- 
Aleksander