Re: [alsa-devel] How to define card specific pcm devices?

On Wed, 2012-09-05 at 12:24 +0100, Girdwood, Liam wrote:

On 5 September 2012 06:41, Tanu Kaskinen tanuk@iki.fi wrote: On Wed, 2012-08-29 at 09:44 +0800, Raymond Yau wrote: > strictly speaking your mic is not a true stereo mic and the channel > map is [left, null] instead of the normal map [left,right] of line-in > or stereo mic

    I think specifying the channel map like you suggest would be a
    good
    solution. Supporting it would require some extra work in
    PulseAudio, but
    I think PulseAudio will anyway have to be extended to query
    the channel
    map information from UCM.

    Now the problem is that UCM doesn't provide the channel map
    information
    at all. Should the channel map be provided in the device
    "Value"
    section? Like this:

    SectionDevice."my-mono-mic" {

            ...

            Value {
                    # Does this value become redundant if
                    # the "CaptureChannelMap" value is added?
                    CaptureChannels "2"

I would expect to see a "1" here unless we cannot open the pcm in mono mode.

                    # Channel names match the constants in
                    # Takashi's proposed channel map API
                    CaptureChannelMap "FL, NA"
            }

    }

This seems fine and should be a simple patch for UCM too. Pulsaudio could use the map information/preference from UCM (like above) to configure the driver using Takashi's new channel map API.

    Opinions? (Liam added to CC - am I right in that you should be
    CC'd in
    all UCM related discussions?)

Yes, please and Mark too (now on CC).

Thanks

Liam