[RfC] Retry registering packet radio to home PLMN when available.

[Denis Kenzior]

Hi Andrew,

So I took this patch and the two earlier patches and applied them.  Thanks.

> Instead of setting DataConnectionManager.Powered to false after
> failed attempts to register to home PLMN with packet radio when
> RoamingAllowed is false, wait for the home PLMN to become available
> retrying everytime the circuit switched radio manages to register
> to home PLMN.  The downside is if the circuit switched radio is off,
> we wait indefinitely.

So I decided to simplify things even further.  Before we can attach we must be 
registered to the network (e.g. COPS issued), otherwise attach fails.  Since 
we need netreg for this anyway, we might as well always rely on netreg's 
registration status to base our attach / detach decisions on.

To me this seems to be the most sensible way to approach this.  However, this 
assumes that the modem can't be registered on netreg and roaming on gprs.

It also might break down in low-signal conditions where packet radio has 
signal but circuit-switched radio doesn't (which is interesting case where 
COPS reports an operator, CGREG shows registered, but CREG shows unregistered)

Comments?

Regards,
-Denis