[pulseaudio-discuss] [PATCHv3 0/4] Read and store UCM data as proplist

[Jorge Eduardo Candelaria]

On May 11, 2011, at 6:43 AM, Colin Guthrie wrote:

> 'Twas brillig, and Jorge Eduardo Candelaria at 10/05/11 21:29 did gyre
> and gimble:
>> This is the third version of the Pulseaudio and UCM integration. 
>> 
>> This set of patches cover adding ucm data to proplist, adding a ucm API
>> to get and set data to proplist, and lets module-alsa-card scan ucm data
>> when the card is probed.
>> 
>> Another set of patches dealing with jack module detection will be sent
>> separately.
> 
> Thanks for this. I believe David will be helping review this stuff, but
> is currently at UDS.
> 
> WRT the jack detection, I think we all agreed that it needs to be
> handled more internally in the alsa code rather than separated as a module.
> 
> I'm not 100% sure of the finer details but I know David had ideas here too.
> 
> We basically need to match up the jack stuff with the appropriate
> sink/source device on the system and then develop a way to automatically
> change sink/source ports accordingly (it may also require that we change
> the card profile too - e.g. change from a 5.1 profile to a stereo
> profile when plugging in stereo headphones).

Unfortunately, the jack matching to source is not that clever yet in the
drivers. :( There is no way to really be sure that Jack X matches stream Y.
This information should be available in the future though (for ASoC drivers
at least) when the DAPM graphs are exported. In the mean time all we can
do is know whether a jack is inserted or removed for a particular sound card.

> 
> I'm not sure how to detect multiple jacks - e.g. if you plug in 3 jacks
> to do 5.1 output, should 5.1 be handled automatically?

Again, this is something that requires better driver and core alsa support.

> 
> Anyway, all the jack detection stuff should be totally separate from UCM
> stuff and could in theory be committed first. UCM should just hook into
> port/profile changes for pushing new configs up to ucm and set the
> appropriate verb+modifiers on the device.

Ok, I'll copy the jack code we have into module-alsa-card. This will allow for simple jack removal/insertion events to be propagated to pulseaudio. We won't be able to do the complicated stuff mentioned above, but should at least be able to do simple speaker/headphone switching. 

> 
> (disclaimer, my UCM foo is still not awesome, but I think this is all
> the consensus we reached on the matter!).
> 
> Col
> 
> -- 
> 
> Colin Guthrie
> gmane(at)colin.guthr.ie
> http://colin.guthr.ie/
> 
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