Re: [RFC] voicecallmanager-api: call related SS signals (proposal)

[Andras Domokos <andras.domokos@nokia.com>]

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Hi Denis,

On 01/27/2011 06:01 PM, ext Denis Kenzior wrote:
> Hi Andras,
>
>> This  becomes a problem when there are multiple calls since it is not
>> possible to determine to which call instance the indication is referring
>> to.
>> This raises the question where/how to show this type of properties?
> Have you seen the thread from Pekka's previous attempt to define such
> APIs?  Its been a while now but should be in the archives.

It seems, we might have a bit work to do here.

The first thing is to settle on  the APIs for handling the voice call SS
notifications, I am thinking about the DBus level API and the oFono
internal API.

Currently the SSI notifications are handled in the call barring code, a
better place for handling those notifications would be under the voice
call atom.

Some of the SSI/SSU notifications should be presented as DBus signals
on the VoiceCallManager interface, others converted to voice call
properties, visible on the VoiceCall interface. I compiled a list of
properties/signals based on the possible SSI/SSU notification. The list
is not complete, but can be expanded any time later, based on practical
needs.

Here is the mapping between the properties/signals and SS notification
codes I considered essential to start with:

VoiceCall properties:
Forwarded (bool):: +CSSI: 2, +CSSU: 0
RemoteHold (bool):: +CSSU: 2, +CSSU: 3
Multiparty (bool): +CSSU: 4

VoiceCallManager signals:
UnconditionalForwardingInEffect: +CSSI: 0
ConditionalForwardingInEffect: +CSSI: 1
OutgoingBarringInEffect: +CSSI: 5
IncomingBarringInEffect: +CSSI: 6

In the case of the VoiceCall properties, it is assumed that call instance
number (call id) is available either implicitly, or explicitly provided 
by the
modem driver. Some of the SSN functions needs to be changed to
add call id to the function parameters list, so that modems supporting
the "call id" feature can deliver this information.
For cases when it's impossible to unambiguously determine the call id
for the SS notifications, the notification will be either discarded, or a
VoiceCallManager DBus could be emitted in connection with the
notification (+CSSU: 2, +CSSU: 3, +CSSU: 4 cases).

I see no any need for the SSN atom, and my proposal is to remove it
completely.

> Regards,
> -Denis

Regrads,
Andras