[pulseaudio-discuss] Splitting a sound card

[Lennart Poettering]

On Fri, 31.08.07 13:19, Tanu Kaskinen (tanuk at iki.fi) wrote:

> On Thu, Aug 30, 2007 at 01:54:17PM +0200, Jan Kasprzak wrote:
> >       I have tried to use "hw:0,0" or "hw:0,1" as a module-alsa-sink
> > argument, but it does not work:
> > 
> > W: alsa-util.c: Unable to attach to mixer hw:0,0: No such file or directory
> > W: alsa-util.c: Unable to attach to mixer hw:0,1: No such file or directory
> 
> Those are just warnings, it probably prints errors too
> before quitting. (It does quit during startup, right?)

BTW: PA always opens hw:0 and not hw:0,0 (at least when
module-hal-detect is used)

> > $ cat /proc/asound/pcm
> > 00-01: VIA 8237 : VIA 8237 : playback 1 : capture 1
> > 00-00: VIA 8237 : VIA 8237 : playback 4 : capture 1
> 
> Hmm... I have to confess that I don't really know how this
> should be interpreted. For a comparsion I'll paste my setup:
> 
> 00-02: ICE1724 Surrounds : ICE1724 Surround PCM : playback 3
> 00-01: IEC1724 IEC958 : IEC1724 IEC958 : playback 1 : capture 1
> 00-00: ICE1724 : ICE1724 : playback 1 : capture 1

Interpretation is simple: the first two numbers tell you the device
and subdevice. i.e. 00-02 corresonds with hw:0,2. The following
strings are device and subdevice name. The next two fields tell you
how many streams may be played back (resp. recorded) in parallel,
i.e. how many times the device may be opened simultaneously (aka "hw
mixing").

On my machine with 4 sound devices this looks like this:

00-01: ES1371/2 : ES1371 DAC1 : playback 1
00-00: ES1371/1 : ES1371 DAC2/ADC : playback 1 : capture 1
01-01: VIA 8237 : VIA 8237 : playback 1 : capture 1
01-00: VIA 8237 : VIA 8237 : playback 4 : capture 1
03-01: Bt87x Analog : Bt87x Analog : capture 1
03-00: Bt87x Digital : Bt87x Digital : capture 1
02-00: USB Audio : USB Audio : playback 1 : capture 1

> If the same logic is applied to your output, hw:0,0 has
> eight channels out and two in. One can just guess, what
> hw:0,1 is in your case. Digital i/o? Modem? Is the sound

I am quite sure that hw:0,0 is analog and hw:0,1 is digital.

> card a separate card or on the motherboard? But you said
> it's a 4-channel sound card. Therefore the four playbacks on
> hw:0,0 are probably mono. Well, that doesn't help us much.
> However, so much is now known (or rather guessed), that all
> needed channels should be on hw:0,0, and thus one loading of
> module-alsa-sink should suffice.
> 
> I made now a test with my own equipment. As said earlier, I
> have 8 channels out. Jack starts (I couldn't test with
> module-alsa-sink, because it doesn't support my card at all)

Hmm, module-alsa-sink doesn't support your card? how so? What happens?

Lennart

-- 
Lennart Poettering                        Red Hat, Inc.
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