Re: [PATCH 3/3] gprs.c: add list contexts for emulator

[Denis Kenzior <denkenz@gmail.com>]

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Hi Bertrand,

On 03/22/2011 10:17 AM, Aygon, Bertrand wrote:
> Hi Denis,
> 
>>> Thanks Denis for your feedback.
>>> The idea behind this code is to propose the complete support of the
>>> usual AT+CGDCONT in the emulator. I think the best solution might be to
>>> stick on contexts exposed over DBus, but this could lead to problems
>>> like : a context is delete throught the DBus interface... how to handle
>>> this change in the AT emulator, and avoid the use of the deleted context ?
>>
>> Personally I'm not convinced CGDCONT management is even a good idea.
>> The typical usecase is for DUN clients to send a CGDCONT string, but
>> this can simply be accepted and ignored (for instance).
> 
> We are not looking at DUN only, but to the 'global' AT Emulator, that will be used during GCF/PTCRB certification.

I know exactly what you want this for.

> During certification, a lot of test require to set some GPRS context with specific parameters. And this cannot go 'directly' to the modem, without going through AP, because the test would not be relevant, or worse will failed, due to disconnect between oFono and modem.
> 

And I know this as well ;)  However, I'm still not convinced.  oFono
simply works differently and you will encounter too many problems doing
it this way.  I listed some of them out already...

>> Just overwriting oFono's context store is not a good idea anyway as you
>> lose certain valuable information.  For instance whether this context is
>> used for internet (and ConnMan should pay attention to it) or it is used
>> for mms, etc.
>>
>> It is also possible for the dial up client to provide context details
>> that are identical to a context already defined in oFono.  In which case
>> those details should be used instead (for the reasons outlined in the
>> previous paragraph)
> 
> So from my point of view, all context must be in sync, in oFono side and modem side.

The reality is doing so is pretty much a bad idea from a technical point
of view.  So sounds like you're in for some fun ;)

Regards,
-Denis