Unable to set preferred mode to 4G from ModemManager for Quectel BG96

[Aleksander Morgado]

Hey

>
> Attached are my log files from MM and qmi-proxy.
>
> This time when I set the preferred mode to 2G via MM, the sequence from AT-cmd did not change (first 4G then 2G). And after setting to 4G, the sequence from modem changed to: first 2G then 4G. See my test sequence below.
>
>
> # mmcli -m 0 --set-allowed-modes='2g|4g' --set-preferred-mode='2g'
>
> successfully set current modes in the modem
>
> # mmcli -m 0 --command="AT+QCFG=\"nwscanseq\""
>
> response: '+QCFG: "nwscanseq",020301'
>
> # mmcli -m 0 --set-allowed-modes='2g|4g' --set-preferred-mode='4g'
>
> successfully set current modes in the modem
>
> # mmcli -m 0 --command="AT+QCFG=\"nwscanseq\""
>
> response: '+QCFG: "nwscanseq",010203'
>

In the log you provided there is only one "Set System Selection
Preference" command, the one switching it to "2G+4G with 2G
preferred". There is no other command for the 2nd operation, and that
means this is very likely a bug in ModemManager. I've opened a new
issue: https://gitlab.freedesktop.org/mobile-broadband/ModemManager/-/issues/473

-- 
Aleksander
https://aleksander.es