Re: Access to SIM card when Modem is not "Powered"

[Denis Kenzior <denkenz@gmail.com>]

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Hi Pekka,

> I want to prevent core from exiting while a modem is in transitional
> state. Before ofonod terminates, it calls disable and waits until
> Powered gets false. I'd rather change Powered to false immediately
> (when modem shutdown starts) but still keep waiting until modem is
> properly powered down.

So the core exits once modems have been powered down and plugins unloaded.  We 
established that already.  I already considered the powered to false 
immediately semantic and discarded it in favor of the current one.  Please 
present an actual argument / use case why you think powered going immediately 
to false is better than the current implementation.

> It seems to me that Marcel and Aki want to control TX power with the
> Powered property. (BTW, there already is a post-sim mechanism to
> control the RX/TX, namely Register/Deregister.)

Register / Deregister refer to something else entirely actually, and the 
modems that do allow Deregister still keep RX/TX circuit on for emergency 
calls.

I think you're expecting oFono to provide more information that it actually 
wants or needs to.  In the end it is up to the modem driver to decide what 
powered off means.  Most simply keep the TX/RX circuits off and the SIM powered 
up, others (like calypso) physically power off the modem.  But even oFono 
doesn't know nor care.

> Currently I'm using config to determine if the isimodem should or
> should not control the modem and which phonet device it should or
> should not use. It is used to determine if ofonod is run with maemo5
> cellular daemons or without them.

You're not helping your case here ;)  Why should oFono care about this use 
case?

In the end I'm fine if you want to implement ofono_modem_unregister that takes 
the modem object off DBus and resets the driver but keeps the attributes 
around.  I know Marcel wanted this anyway for something else.

> You don't seem to handle modem resets at all. Once atdriver gets so
> far, other hardware will benefit, too.

As you mentioned earlier, modem resets are handled by setting the modem 
powered=off then true.  

> What we miss from the core is a way to do asynchronous cleanup
> (separate from Powered). A shutdown() method in modem driver and
> corresponding callback, like ofono_modem_shutdown_ready(). This way we
> can do what ever N900 requires us to do and there is no need to touch
> other drivers.
> 

Send a patch with your proposal.  So far I like the idea of disable having a 
hint on whether a shutdown is in progress more than an explicit shutdown 
method.  

Regards,
-Denis