On Mon, 2012-05-07 at 13:02 -0700, David Henningsson wrote: > 2012-05-07 03:47, Tanu Kaskinen skrev: > > 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, > > I agree with Arun on this one. Besides, it is not obvious to me what the > channel mapping should be either, and couldn't that vary between > different 4-channel hardware? Is the aux* just causing all inputs to be > added for whatever the client wants to have...? > > > and I doubt udev can be used to query the amount of supported > > channels. > Hmm...that raises a thought I didn't consider before. Why don't we do > this in alsa-lib? If this varies between devices, we could create e g, > for 4-channel mic hardware A, we set up a alsa-lib ttable to have > "front" record two channels, the two left ones mixing in to the left and > the two right ones mixing into the right. Or in what way do we actually > use all four channels today? The separate mics may eventually be useful for beamforming and associated processing. Would your approach require changes to alsa-lib again if we wanted to do that? If yes, it might be better to let PulseAudio take care of this. -- Arun
