GPRS support for Ofono

[Bastian, Waldo]

> > > I know why you want this, but I'm still against the counter being an
> > > oFono driver API.  There needs to be a proper kernel interface that
> > > signals the application when an interface has gone away with the rx/tx
> > > details.  This way we handle this generically for all modems without
> > > relying on some intrinsic hardware capabilities.
> >
> > This still doesn't solve the case where the modem is accessed from a PC
> > client and forwards PPP data as that data will not go through any
> > network interface, e.g. BT DUN or USB tethering.
> 
> The cases you describe imply that oFono is not even in control of the gprs
> context.  How would we track/report the tx/rx statistics in that case?

It's probably difficult if the PC client is allowed to redefine GPRS contexts, but otherwise oFono should at least be able to report the total tx/rx for the context's it has defined. The BT DUN / USB bridge could call into oFono and trigger a poll of all the stats to update them, e.g. when a BT DUN connection is disconnected.

> > The modem is really in the best position to provide the most reliable
> > information on data usage. You can still use statistics from the network
> > interfaces as a fall-back in case the modem can not provide this
> > information.
> 
> I don't disagree, but not every modem can track these statistics and this
> isn't described by 27.007.  I suggest the initial support should be
> enabled by the modem driver implementing a custom D-Bus interface and 
> expose these details however it wishes.

The modem driver has no desires of its own :-) It really comes down to what the UI needs and I doubt that the UI wants to deal with this on a modem by modem basis, but sure it's a possibility.

Cheers,
Waldo