To enable the new audio channel service in gaia, we need to let System app know which app is using the telephony channel, because the telephony channel does not use media element to produce sounds, there will be no event when the telephony channel activates. Bug 1129882 will introduce a new api for telephony's audio channel, it's: |Telephony.ownAudioChannel()| So after/before the api landed, we need to call it in Callscreen app so that the System app is able to manage the telephony audio channel.

(In reply to Dominic Kuo [:dkuo] from comment #0) > So after/before the api landed, we need to call it in Callscreen app so that > the System app is able to manage the telephony audio channel. Can you elaborate when this call has to be made? At the beginning of a call?

(In reply to Gabriele Svelto [:gsvelto] from comment #1) > Can you elaborate when this call has to be made? At the beginning of a call? The main goal to call this api is to let the System's audio channel service knows about Callscreen will be using the telephony channel, we can say it's the initialization of audio channel. So if possible, it's better to do it before a call actually comes, not to wait the ril state changes. But I don't know the Callscreen code well, you guys should be able to make better judgement than me, if there are concerns, like performance regression.

I think this should be implemented before landing the new architecture of the audio channel. Since the JS can detect whether the specific function exists, if it doesn't, we can ignore it.

Gabriele, would you please review this? thanks.

Comment on attachment 8616605 [details] patch As per comment 3 there's no problem in landing this as is.

Thanks Gabriele :) master: https://github.com/mozilla-b2g/gaia/commit/314cc9b2b56cfef14875101f2350aa3be15e7cae