[pulseaudio-discuss] [PATCH 0/2] Patches for supporting ALSA UCM

Colin Guthrie gmane at colin.guthr.ie
Fri Nov 4 03:12:32 PDT 2011


'Twas brillig, and Janos Kovacs at 03/11/11 16:00 did gyre and gimble:
>> I'm a little confused by this. Can someone give some history as to this
>> patcheset?
> Sorry about the confusion. Among others, Jaska and myself were in the team that
> developed the policy engine for Maemo and later for MeeGo. The Nokia N900 and
> the recently launched N9 uses that engine. When we started PA had
> nothing in this
> area so we built our policy enforcement point as a PA module. It basically made
> audio routing, muting and corking.

Great, thanks for the clarification :)

> Recently we joined Intel where the mission somewhat similar. From our
> point of view
> UCM has many limitations, the use case model is not a natural fit to
> PA  but it has a
> very appealing feature: the logical devices e.g. 'speaker', 'headset',
> 'headphone' etc.
> Those would allow to make policies, or UI's to specify preferences, easier IMO.

Good news. Glad to see Intel is still committed to the cause :D

> Last month I posted some preliminary ideas on this mailing list
> (Subject: [pulseaudio-discuss] Audio routing policy). I tried to
> prototype those ideas
> to see how they would work in practice.

Ahh yes. This was very much on my to-read list before the 1.0 release,
but as time was limited I was waiting until after the release to read
it. Then my whole mail folder got broken and I lost all the metadata as
to which mails were read and not... that's kinda knocked me out of
kilter a bit so apologies on that front.

>> Was id developed completely independantly from the other patches
>> relating to UCM?
> I was looking into some other patches (Margarita Olaya's for instance) but
> at the end I decided to make a fresh start. I built my proto top on David's
> original jack-detection patches, that used input devices, to make the
> generated ports automatically enabled/disabled. Recently I had to shift to
> the new 6 patch set.

Cool. That's good that you're building on top of David's work here :)

>> Or has this come out of our UCM related discussions in Prague recently
>> somehow passed on to yourself?
> Now, I was not there and have no idea what was discussed there.

OK, so Arun will be publishing a blog on that in the next day or so He's
just waiting to ensure his recollection/writeup is accurate by getting
feedback from the parties involved should be available soon via the
PulseAudio planet blog aggregator, tho' I'm sure he'll post here too.
Speaking of the blog stuff, do you guys write about audio related stuff
much with your role at Intel? If so, if you could give me a link to a
suitable RSS feed so I can include it, that would be most awesome!

>> I'm a little concerned that people are just pushing patches into PA
>> without getting the overall design right here (I've not looked at your
>> patches so this is just a general concern, not anything specific to your
>> work).
> Actually, my intention was that PA folks will have a look on this prototype
> and say whether this approach is OK or not. So any comment, critics,
> proposal etc. is really warmly welcomed.

Great. I think there will be some Linaro/Canonical folks happy to give
feedback and I'll try my best myself to start getting my head wrapped
around this.



Colin Guthrie

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