Hey Fredrik, >> > > We’re facing a problem where ModemManager (v1.10.0) doesn’t respect the >> > > allowed modes when the modem (Quectel BG96) fails to connect the first >> > > try. >> > > >> > > First, we set the allowed modes to 4G (--set-allowed-modes=4g) which >> > > works. We verified this by running AT+QCFG=“nwscanmode” which is >> > > correctly set to “3” after running the command. When NetworkManager then >> > > issues a simple connect, ModemManager launches an automatic network >> > > registration which appears to reset the allowed modes. Querying >> > > nwscanmode afterwards yields “0” which corresponds to all modes (2g+4g). >> > > >> >> > > How can we make the allowed modes setting stick (preferably across >> > > module restarts/resets as well)? >> > >> > So it seems it's this next "NAS Initiate Network Register" the one >> > that ends up resetting the nwscanmode setting. >> > >> >> It looks like we shouldn't even be using NAS Initiate Network Register >> if Set System Selection Preference is supported, because the >> functionality of the former is already available in the latter. My >> assumption therefore is that if we switch to use SSSP, the mode >> preference settings may be preserved. >> >> Anyway, if you could please do the Get System Selection Preference >> check before and after the Initiate Network Register, that would be >> awesome to confirm this. > > > Hi Aleksander! Thanks for your quick reply. I'm working with Sven on this one. > > Yes, it seems the settings in Get System Selection Preference are also reset > when the network scan times out. Here is the qmicli output just after setting > the allowed mode to 4G: > > $ mmcli -m 0 --set-allowed-modes 4g > successfully set current modes in the modem > $ qmicli -d /dev/cdc-wdm0 -p --nas-get-system-selection-preference > [/dev/cdc-wdm0] Successfully got system selection preference > Emergency mode: 'no' > Mode preference: 'lte' > Band preference: 'gsm-dcs-1800, gsm-900-extended, gsm-900-primary, gsm-850, > gsm-pcs-1900' > LTE band preference: '1, 2, 3, 4, 5, 8, 12, 13, 17, 18, 19, 20, 26, 28, 39' > Network selection preference: 'automatic' > Service domain preference: 'cs-ps' > GSM/WCDMA acquisition order preference: 'gsm' > Acquisition order preference: lte, none, none, gsm > > After timeout and the new Initiate Network Register: > > $ qmicli -d /dev/cdc-wdm0 -p --nas-get-system-selection-preference > [/dev/cdc-wdm0] Successfully got system selection preference > Emergency mode: 'no' > Mode preference: 'gsm, lte' > Band preference: 'gsm-dcs-1800, gsm-900-extended, gsm-900-primary, gsm-850, > gsm-pcs-1900' > LTE band preference: '1, 2, 3, 4, 5, 8, 12, 13, 17, 18, 19, 20, 26, 28, 39' > Network selection preference: 'automatic' > Service domain preference: 'cs-ps' > GSM/WCDMA acquisition order preference: 'gsm' > Acquisition order preference: lte, none, none, gsm >
Yes, this confirms the assumption. We should try to use SSSP for the manual/automatic registration attempt. > I just noticed that after completing the procedure above, I am unable to use > mmcli > to set the preferred mode at all. Polling nwscanmode returns '0'. This is > fixed by > restarting ModemManager. > > $ mmcli -m 0 --set-allowed-modes 4g > successfully set current modes in the modem > $ qmicli -d /dev/cdc-wdm0 -p --nas-get-system-selection-preference > [/dev/cdc-wdm0] Successfully got system selection preference > Emergency mode: 'no' > Mode preference: 'gsm, lte' > Band preference: 'gsm-dcs-1800, gsm-900-extended, gsm-900-primary, gsm-850, > gsm-pcs-1900' > LTE band preference: '1, 2, 3, 4, 5, 8, 12, 13, 17, 18, 19, 20, 26, 28, 39' > Network selection preference: 'automatic' > Service domain preference: 'cs-ps' > GSM/WCDMA acquisition order preference: 'gsm' > Acquisition order preference: lte, none, none, gsm > Ahh, that is just because internally MM daemon has cached that the modes allowed is 4G only, so attempting to re-set 4G only won't send any command to the modem. MM didn't detect that those settings were changed "behind its back". If you try to change it to 3G+4G and then to 4G-only, it should work. Anyway, this issue will be solved along with the one above, it's just a side effect of the original problem. -- Aleksander https://aleksander.es _______________________________________________ ModemManager-devel mailing list ModemManager-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/modemmanager-devel
