Re: nmcli radio off connected to ModemManager power state low

[Dan Williams <dcbw redhat com>]

On Sun, 2016-03-13 at 18:23 +0100, c lobrano gmail com wrote:
> I'm sorry, I think I explained myself wrong.
>
> CFUN=4 is ok for radio off, I wanted to say that some plugins might
> not 
> use CFUN=4 for "power low".
> In Telit modem, as example, I might use CFUN=5 "mobile full 
> functionality with power saving enabled" and CFUN=4 for power off,
> but 
> doing so "nmcli radio off" won't shut down the radio (without
> rfkill).

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.

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 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.

Dan

> Carlo
>
> On dom, mar 13, 2016 at 5:47 , Aleksander Morgado 
> <aleksander aleksander es> wrote:
> > On Sun, Mar 13, 2016 at 1:56 PM, Carlo Lobrano <c lobrano gmail com
> > >  
> > wrote:
> > > >  The problem is that if the modem is totally powered off with
> > > > a 
> > > > CFUN=0,
> > >  then how do we power it back on? CFUN=4, where the modem is
> > > still
> > >
> > >  alive but with radio off is already more than enough in most
> > > cases.
> > > >  Why do you need the modem to be totally off?
> > >  In power low I could expect that the modem goes in some kind of 
> > > power saving
> > >  configuration but still connected to the network, it really
> > > depends 
> > > on the
> > >  modem capabilities, and when rfkill is not available, the modem
> > > is 
> > > only set
> > >  in power low, which may not be the same as radio off.
> > >
> > >  I totally understand the problem though, modems that use CFUN=0
> > > to 
> > > power off
> > >  are not listening to any command to put them ON again.
> > >
> > >  I will look better to rfkill, but I still see a possible 
> > > misunderstanding
> > >  between power low intended as radio off and power low intended
> > > as 
> > > power
> > >  saving.
> > Is there any case in which CFUN=4 doesn't mean radio off? Maybe we 
> > got it wrong.
> >
> > --
> > Aleksander
> > https://aleksander.es