Re: [PATCH] doc: Add modem Type property

[Denis Kenzior <denkenz@gmail.com>]

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Hi Lei,

On 01/21/2011 03:48 PM, Lei Yu wrote:
> Hi Denis,
> 
> On 01/21/2011 01:04 PM, ext Denis Kenzior wrote:
>> Hi Lei,
>>
>>>>> +        string Type [readonly, optional, experimental]
>>>>> +
>>>>> +            String representing the type of the modem device.
>>>>> +
>>>>> +            The possible values are:
>>>>> +                "gsm"     Modem supports one or more of the 3GPP
>>>>> +                    family of technologies including GSM,
>>>>> +                    EDGE, UMTS, HSPA, LTE.
>>>>> +                "cdma"  Modem supports one or more of the 3GPP2
>>>>> +                    family of technologies including CDMA 1x,
>>>>> +                    EVDO.
>>>>> +                "hfp"    Bluetooth hands-free profile (HFP) modem
>>>>> +
>>>>
>>>> So one pointed question:
>>>>
>>>> How are we planning to support dual-mode devices with this property?  I
>>>> believe during the CDMA workshop we decided that the clients should
>>>> simply look at the set of interfaces, not a semi-static property...
>>>
>>> We understand that the decision during the CDMA workshop but as we
>>> explained one use case in the cover letter
>>> (http://lists.ofono.org/pipermail/ofono/2011-January/007890.html) for
>>> this RFC, there will be cases where atom's D-Bus I/F is not suitable (or
>>> as a reliable way) for telling what is current mode (CDMA or GSM). E.g.,
>>> in the case of retrieving serial number from modem. Currently both CDMA
>>> and GSM shares the same I/F (ofono.org.modem) rather than having
>>> separate (ofono.org.cdma.modem). And, further if no other atom has been
>>> instantiated, then, there will be no other way to tell which mode (CDMA
>>> or GSM) the modem is. And, further for displaying serial number, upper
>>> layer will need to know it is CDMA or GSM. In case of CDMA, the serial
>>> number is MEID and GSM it is IMEI. As explained in cover letter, we
>>> anticipate more cases like this.
>>
>> So let us say I have a dual-mode modem.  Are there now two serial
>> numbers? One for MEID and one for IMEI?  Are there now two
>> Manufacturers? Two Revisions?
> 
> Try to clarify what you try to ask first. Let's start with the dual-mode
> case where the modem is integrated modem (one piece of HW) where it
> supports both CDMA and GSM. Then, there is case where the phone actually
> has both MEID and IMEI. And, these two numbers are actually the same
> (note, per IMEI's assignment there is a pre-arranged segment for this
> kind of world phone). And, in which case, one manufacture, one revision.
> Per the other thread, in which case the "Type" will be something like
> "gsm_cdma".

So how does the modem type help you here if you have 'gsm_cdma'?  Is the
modem giving you a MEID? An IMEI?  I'm not convinced the Type helps you
in any way.  It might help you for HFP, but certainly not the dual mode
case.

> Of course, there can be case where two physical modems are in the device
> in which case there will be two separate serial numbers and two
> manufacturers and revisions. I am assuming you are not asking for this
> case.

Yes, I'm ignoring the true dual-mode dual-radio case right now.

Regards,
-Denis