[pulseaudio-discuss] [PATCH v2] alsa: Add support for sound cards with 4-channel input.

[Arun Raghavan]

On Mon, 2012-05-07 at 13:47 +0300, Tanu Kaskinen wrote:
> On Mon, 2012-05-07 at 09:46 +0530, Arun Raghavan wrote:
> > On Tue, 2012-05-01 at 20:09 +0300, Tanu Kaskinen wrote:
> > > Changes in v2:
> > >  - Call the mapping a generic 4-channel input mapping
> > >    instead of a 4-channel mic array mapping. The mapping
> > >    will be used also by sound cards that have two stereo
> > >    input jacks, so in those cases talking about mic arrays
> > >    is wrong.
> > >  - Added a comment about using the "hw" device name.
> > > 
> > > BugLink: https://bugs.freedesktop.org/show_bug.cgi?id=45813
> > > ---
> > >  src/modules/alsa/alsa-mixer.c                    |    1 +
> > >  src/modules/alsa/mixer/profile-sets/default.conf |    9 +++++++++
> > >  2 files changed, 10 insertions(+)
> > > 
> > > diff --git a/src/modules/alsa/alsa-mixer.c b/src/modules/alsa/alsa-mixer.c
> > > index abb12ee..8b54f75 100644
> > > --- a/src/modules/alsa/alsa-mixer.c
> > > +++ b/src/modules/alsa/alsa-mixer.c
> > > @@ -3888,6 +3888,7 @@ static int mapping_verify(pa_alsa_mapping *m, const pa_channel_map *bonus) {
> > >          { "analog-surround-61",     N_("Analog Surround 6.1") },
> > >          { "analog-surround-70",     N_("Analog Surround 7.0") },
> > >          { "analog-surround-71",     N_("Analog Surround 7.1") },
> > > +        { "analog-4-channel-input", N_("Analog 4-channel Input") },
> > 
> > Since this is limited to some specific hardware, shouldn't we set up
> > udev rules instead of always probing?
> 
> "All devices supporting 4-channel input" isn't very specific hardware
> IMHO, and I doubt udev can be used to query the amount of supported
> channels. But if you think that the new mapping really causes too much
> overhead for the common case, I can live with udev rules too (I think
> caching the probe results would be a better solution for the performance
> problems, but that's not available right now).

I was under the impression that it was primarily the PS3 Eye and Kinect
folks complaining about it. If 4 mic arrays are more common than just
that, go ahead and push it. :)

-- Arun