The following issue is causing us some grief and I really need some guidance on how to approach this. This is being sent to both the ofono and connman mailing lists because it's not really clear to me who's doing the right/wrong thing here...

The connman ofono plugin does the following:
i)  It powers up (enables) the modem
ii)  If cellular tech is enabled, it brings the modem online

For an LTE-modem, this second step results in a default bearer being attached and thereby the modem is 'connected'. The third connman step, setting the ofono context to Active, is not required for LTE; the context becomes 'Active=true' right away.

The above effectively means that it's not possible to have an LTE modem that does not auto-connect (in connman terms).

Now the APN that ofono sets on the LTE context is 'automatic'; that was selected because connman _requires_ some APN or else it ignores the context altogther.

If the modem roams away from LTE connectivity and wants to fallback to UMTS/GSM, it needs another context with a valid APN. So now the modem has two 'internet' contexts ('automatic' and APN) which connman presents as two distinct services.

These two services, as far as I can tell, end up competing with each other when connecting and a mess ensues... if the lower numbered context is the 3G context, connman goes into an endless loop attempting to set it Active and continuously failing when the tech switches to LTE.

The question is, what are the expectations here:
i) What does it mean for connman to see two 'internet' contexts since it sets up two services for them? ii) How is a modem supposed to roam between LTE and UMTS/GSM networks when one requires an APN and the other does not. iii) Not auto-connecting an LTE modem means not bringing it online; what implications does this have for connman?

The above is currently a bit of a confusing mess and both ofono and connman get themselves tied in a knot when the modem switches between LTE and non-LTE techs. Any guidance on how to approach this would be appreciated.

Thanks,
Jonas



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