Modem interface initialization

[Aleksander Morgado]

Hey,

>
> On Mon, Aug 22, 2022 at 2:14 PM Aleksander Morgado
> <aleksandermj at chromium.org> wrote:
> > In general, what I always suggest is that if you're changing settings
> > in the modem that may affect how ModemManager manages the device, then
> > you should change those settings only if ModemManager is not using the
> > device.
>
> Let me clarify my question. It is related to an embedded device where
> human interaction
> is not expected. If required parameter was set earlier, modem reboot
> shall be avoided to reduce
> connection setup time (or downtime) and network signalling overhead.
> As I understand, your suggestion above related to any external change
> to the modem config.
> because doing the change in inside a plugin would keep device in use.
> So, the question: is there a way to run something like "at+cfun=1,1"
> from some place like
> mm-broadband-modem-vendor.c without crashing MM?
>

Yes, with caution. One recent example; changing the initial EPS bearer
settings in some modems requires the modem to be with RF off, so the
logic changing those settings inside MM will put the modem in low
power mode briefly, change the settings, and then recover the original
power setting the modem had.

> > A different approach would be to have the modem configuration change
> > done on boot and synchronize it so that MM doesn't start until the
> > configuration changes have been made.
> Well, this is a safest bet and a current option.
>

I agree.

-- 
Aleksander