Restrict modem (EC21) one of 3G or 4G - ModemManager 1.10.0 (Debian Buster)

[Enrico Mioso]

BTW, Quectel EC25, I am not able to set allowed modes to 2g,3g,4g and preferred mode to any.
Any solution? :D


On Wed, 21 Oct 2020, Brendan Simon (eTRIX) wrote:

> Date: Wed, 21 Oct 2020 06:59:28
> From: "Brendan Simon (eTRIX)" <brendan.simon at etrix.com.au>
> To: Aleksander Morgado <aleksander at aleksander.es>
> Cc: "ModemManager (development)" <modemmanager-devel at lists.freedesktop.org>
> Subject: Re: Restrict modem (EC21) one of 3G or 4G - ModemManager 1.10.0
>     (Debian Buster)
> 
> On 19/08/2020 2:13 am, Aleksander Morgado wrote:
> 
> This may be a known issue with QMI modems where the internal network
> registration attempt is done with "QMI NAS Register In Network"; this
> command not only registers in network, it also makes the access tech
> preference fallback to "any", and MM doesn't consider that in its API.
> 
> There is a recent patch to avoid this, by avoiding the use of "NAS
> Register in Network" and use "NAS Set System Selection Preference"
> instead: https://gitlab.freedesktop.org/mobile-broadband/ModemManager/-/comm
> it/c70b3557184fdf1472ff0cb36e9fd937cc7f9024
> 
> That patch is not yet in any release, though, not even in 1.14.0. I'll
> backport it to the 1.14.x branch so that it gets into 1.14.2.
> 
> 
> So the 64 million dollar question is when is 1.14.2 likely to be released ?
> 
> Sometime in the next few weeks I'd say.
> 
> 
> So it's been a while, but I now have MM 1.14.2 installed on my embedded
> system via Debian Buster Backports repo.
> 
> I can successfully set the allowed mode to "3G" and get a UMTS connection.
> 
>     mmcli -m 0 --set-allowed-modes="3G"
> 
> However, if I try to lock to 4G the connection never succeeds.
> 
>     mmcli -m 0 --set-allowed-modes="4G"
> 
> The only way I can get an LTE connection is with the following.
> 
>     mmcli -m 0 --set-allowed-modes="3G|4G" --set-preferred-mode=4G
> 
> I presume this is a bug?  But maybe there is something else going on?
> Any ideas or suggestions to get an LTE connection with setting 4G as the
> only allowed mode?
> 
> Also, I've just noticed that 1.14.6 has just hit the Buster Backport repo. 
> I'm not sure if that will help or not, but I don't see anything in the NEWS
> file that would suggest a change in this area.
> 
>     https://github.com/freedesktop/ModemManager/blob/mm-1-14/NEWS
> 
> Thanks, Brendan.
> 
> 
>