Disconnect with non LTE capable provider

[Aleksander Morgado]

Hey Guido,

Adding Ben and Franko in CC, who should be interested in this issue.

> the umts modem in my laptop (Huawei ME906E) is LTE capable while my
> provider isn't. Whenever the modem sees LTE it tries to upgrade the
> connection and then disconnects:
>
> ModemManager[3010]: <info>  Modem /org/freedesktop/ModemManager1/Modem/0: 3GPP Registration state changed (home -> idle)
> ModemManager[3010]: <info>  Modem /org/freedesktop/ModemManager1/Modem/0: 3GPP location updated (MCC: '0', MNC: '0', Location area code: '0', Cell ID: '0')
> ModemManager[3010]: <info>  Modem /org/freedesktop/ModemManager1/Modem/0: access technology changed (umts -> lte)
> ModemManager[3010]: <info>  Modem /org/freedesktop/ModemManager1/Modem/0: signal quality updated (26)
> ModemManager[3010]: <info>  Modem /org/freedesktop/ModemManager1/Modem/0: state changed (connected -> disconnecting)
>
> This is ModemManger 1.2 and connected via
>
>     mmcli -v -m 0 --simple-connect="apn=internet"
>
> (but it's the same using NM). I wonder how to disable LTE for these
> situations and how to expose this in a user friendly way in NM since
> this might be a rather common problem.

How about disallowing 4G temporarily? You could do:
  mmcli -m0  --set-allowed-modes="2g|3g"

The ME906E should be happy with the latest SYSCFGEX changes I did for
allowed/preferred mode switching.

Note that the connection settings for broadband devices in
*NetworkManager* still have the 'allowed+preferred' modes
configuration, *but* those are now ignored by MM >= 1.0. The correct
way to handle capabilities and/or mode switching is not to add it as a
per-connection configuration as it was before (we don't want to change
those just before attempting a connection), but instead the UI should
have some mechanism to change those values without even needing to
fire a connection. I have my own ideas for GNOME3 to add this setup in
the Network Settings, just not enough time to get them implemented.

-- 
Aleksander