[pulseaudio-discuss] Headset-detection

Colin Guthrie gmane at colin.guthr.ie
Thu Jul 21 13:22:08 PDT 2011

'Twas brillig, and Colin Guthrie at 21/07/11 21:12 did gyre and gimble:
> 'Twas brillig, and Himanshu Chug at 21/07/11 08:24 did gyre and gimble:
>> 2 Currently our Kernel/ALSA team support for providing seperate kcontrol
>> (amixer scripts) for enabling/disabling loudspeaker and headset to PA,
>> so it might be an good idea to handle Jack detection and routing in one
>> of the existing module or write up an new jack detection module for
>> this, as Colin suggested, provided that we are able to recognize Jack
>> device type  (input/mic or output/headset or both)  from point 1, ( i
>> will take further help from kernel team here about detecting jack device
>> type, but any suggestions are welcome :-) )
> Kinda. PA should be able to display to you the different "ports" for
> each sink. These ports represent the Speakers or the Headphones
> kcontrols that are on your device and you can change ports at runtime
> (just run pavucontrol and if your sinks actually have ports, there will
> be a drop downo n the "Output Devices" pane). At present you have to
> change ports manually but the plan is to hook this up to jack detection,
> such that the port is simply flipped accordingly.
> Multifunction jacks (i.e. those that can be input or output, analog or
> digital) are even more interesting :)

I forgot to mention, but these "ports" are detected with "mixer paths"
that are textual descriptions of how to parse the alsa kcontrols in a
semi-sensible way (as you can imagine, most hardware varies wildly in
what they call the kcontrols. While we do very much try to push standard
naming of the kcontrols to the drivers, we do still have to cope with a
few strange naming schemes. One thing you could do for us is to make
sure you kernel guys are using the standard names here :D

If you have specific hardware it may make sense for you to write your
own mixer path profile. It won't automatically make things with with
regards to jack detection but it'll maybe present your hardware more
sensibly to PA.

Alex (a new contributor \o/) just wrote a nice new Wiki page about
writing these mixer path profiles.

It might be of use to you..



Colin Guthrie

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