Re: [PATCH 1/1] qmi: support SMS receive on Quectel EC21

[Denis Kenzior <denkenz@gmail.com>]

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On 10/17/2017 06:41 AM, Alexander Couzens wrote:
> Hi Jonas,
> 
>> Could you explain what you are trying to do here?  Why would you
>> clear the SMS storage every time the modem powers up?
>>
>> I also don't see that ofono actually supports deleting messages from
>> the modem's storage... if you know how this is supposed to work,
>> please enlighten me.

oFono does not manage the message store.  The implicit assumption is 
that all SMS messages are delivered immediately without hitting ME/SMS 
storage.  oFono takes care of notifying the history plugin and sending 
the ACK.

For those devices that don't support immediate delivery it is assumed 
that the sms atom driver takes care of the details.  So on startup the 
driver is supposed to grab all messages from the store, notify the core 
and then delete all of them.  Any subsequent messages that are delivered 
to the store, should be notified up to the core and the storage space freed.

See how the atmodem sms driver does this.  E.g. +CMTI delivery vs +CMT

> 
> the Gobi2000 doesn't accept the routes with TRANSFER_AND_ACK nor
> STORAGE_TYPE_NONE.
> 
> Reading out the store is also useful if the modem is receiving any
> SMS while ofono isn't runing. E.g. while booting, the sms would never
> made it to ofono.

This is a weird case as the modem should not be in radio on mode anyway. 
  But yes this is possible...

> 
> I don't know (yet) how the different routes are working in detail. This
> is on my list. But I've faced edge cases when the NV was full, the
> modem rejects receiving any messages, regardless if the modem should
> save it to it.
> 

On an unrelated note, can you guys look at the WIP mbimmodem plugin and 
see if the parsing/building approach taken there is applicable (in some 
modified form) to QMI?  E.g. to simplify the drudgery of building / 
parsing QMI messages.

Regards,
-Denis