That's perfectly clear :)

> We could always add a new "--set-power-saving" operation that can be
> run at any time, when modem enabled or disabled. If modem is disabled
> and we set "power saving" state, we cache that request and once we
> enable the modem we could issue a CFUN=5 instead of CFUN=1. If the
> modem is enabled when we set "power saving" state, we just do the
> CFUN=5 right away.

that would be very interesting.

Thanks a lot,
Carlo

On 15 March 2016 at 09:02, Aleksander Morgado <[email protected]>
wrote:

> On Mon, Mar 14, 2016 at 5:01 PM, Carlo Lobrano <[email protected]>
> wrote:
> >> I'm not entirely sure what you mean with "power off" and "shut down the
> >> radio", but here are the definitions I'm using:
> >> power off: the entire modem is powered off not just the radio.  The
> >> device does not communicate with the host because it is unpowered.
> >>
> >> radio off: the radio is powered down and no network communication is
> >> possible, but the modem can still communicate with the host.
> >
> > clear, the same as mine.
> >
> > So, saying that my targets are ModemManager Telit plugin's
> modem_power_down
> > and modem_power_off functions, we have:
> >
> > * modem_power_off (which is not implemented) == power off.
> >   Ideally, CFUN=0 would be the candidate, but it would make the modem
> > unrecoverable, so CFUN=4 would be my choice, which is OK, if I understood
> > correcly.
> >
>
> Well, I think you can do CFUN=0 for the power off. Power off assumes
> that the modem may get totally removed after the command, as in the
> log we print:
>
>         mm_info ("Modem powered off... may no longer be accessible");
>
> The purpose of the power off as it is, is to shutdown the modem, even
> if we cannot access it any more. A use case would be when you have a
> externally powered modem, and you want the modem to totally shutdown
> cleanly before cutting the power to it, for example.
>
> > * modem_power_down is currently implemented with CFUN=4 so == radio off.
> >   However, considering that it is activated with "mmcli -m <ID>
> > --set-power-low", it looks to me as a function that puts the modem in a
> > "power saving state", for which Telit's CFUN=5 would be more appropriate.
> >   The problem is that if I change modem_power_down to CFUN=5, when I use
> > "nmcli radio off" ModemManager will send CFUN=5, which is not a "radio
> off"
> > state.
> >   So, the question is, "mmcli -i <ID> --state-power-low" is to be
> considered
> > like "go to power save" or "radio off"?
> >
>
> "power low" as MM sees it is more like "radio off", not as "power
> saving mode". Just think that when you switch off the radio, the power
> consumed goes very low :)
>
> >
> >> The ModemManager API specification would not allow CFUN=5 for the
> >> "disabled" state, since it defines the disabled state as not allowing
> >> network communication.  So I would still use CFUN=4 for "disabled"
> >> state.
> >
> > But, if I got it right, I can't override mm_modem_disable for a plugin,
> > right? When I disable the modem (mmcli -m ID --disable) no AT+CFUN
> command
> > is sent to the modem.
> >
>
> No functionality/power change is ever done automatically in the modem
> disabling step. There was some time where we did the low-power
> switching automatically as a step in disabling, but we removed that.
> So.:
>
>  * Modem enable does an implicit change to full functionality mode: CFUN=1
>  * Modem disable does not change the functionality mode.
>  * You can only go to low-power mode when the modem is in disabled state:
> CFUN=4
>
> >> But couldn't the modem instead be set to CFUN=5 whenever it is
> >> enabled?  The Telit docs seem to say it's a fully functional state,
> >> just that the modem can do some power saving.  Which sounds like a win
> >> without a downside.
> >
> > I guess that moving in and out from a power saving state would cost some
> > time (and maybe overhead?) respect CFUN=1 which should be more
> responsive.
> > Moreover, I would expect to get into a power saving state issuing
> > --set-power-low more that with --set-power-on.
>
> We could always add a new "--set-power-saving" operation that can be
> run at any time, when modem enabled or disabled. If modem is disabled
> and we set "power saving" state, we cache that request and once we
> enable the modem we could issue a CFUN=5 instead of CFUN=1. If the
> modem is enabled when we set "power saving" state, we just do the
> CFUN=5 right away.
>
>
> --
> Aleksander
> https://aleksander.es
>
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