MC7710 "forgetting" RAT

[Aleksander Morgado]

>>
>> I did some more testing and it looks like I found a systematic behaviour:
>> - I boot the system and check the RAT value using AT commands, it looks
>> okay.
>> - I start ModemManager in one terminal and wait until the modem is
>> available
>> - I use a second terminal to perform a mmcli --simple-connect
>>   => Exactly here it hangs, it won't connect.
>>
>> If I quit ModemManager then and check the RAT value on the AT port again I
>> get the invalid value.
>>
>> As you've said that you don't set anything related to the RAT within
>> simple-connect I can only guess that the firmware doesn't understand
>> something it receives in that process, right?
>
> It is probably worth noting that the AT!SELRAT command affects the same
> firmware settings as QMI, but does a combination of "technology" and
> "system-selection" preferences.
>
> So if MM touches any QMI setting, then this will be directly reflected
> in the AT command.  For example:
>
> bjorn at nemi:~$ qmicli -d /dev/cdc-wdm0   --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-pcs-1900, wcdma-2100, wcdma-900'
>         LTE band preference: '1, 3, 7, 8, 20'
>         Roaming preference: 'any'
>         Network selection preference: 'automatic'
>         Service domain preference: 'ps-only'
>         Service selection preference: 'automatic'
>
> at!selrat?
> !SELRAT: 06, LTE Only
>
>
> OK
>
>
> bjorn at nemi:~$ qmicli -d /dev/cdc-wdm0 --nas-set-system-selection-preference='gsm|umts|lte'
> [/dev/cdc-wdm0] System selection preference set successfully; replug your device.
> bjorn at nemi:~$ qmicli -d /dev/cdc-wdm0   --nas-get-system-selection-preference
> [/dev/cdc-wdm0] Successfully got system selection preference
>         Emergency mode: 'no'
>         Mode preference: 'gsm, umts, lte'
>         Band preference: 'gsm-dcs-1800, gsm-900-extended, gsm-900-primary, gsm-pcs-1900, wcdma-2100, wcdma-900'
>         LTE band preference: '1, 3, 7, 8, 20'
>         Roaming preference: 'any'
>         Network selection preference: 'automatic'
>         Service domain preference: 'ps-only'
>         Service selection preference: 'automatic'
>
>
> at!selrat?
> !SELRAT: 07, GSM, UMTS, LTE
>
>
> OK
>

The weird thing is that by default MM won't don any 'set' operation in
QMI; only 'get' operations; unless of course a set action is requested
by the user through MM's DBus interface.

-- 
Aleksander