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From: Clemens Ladisch on 4 May 2010 10:23
houghi wrote:
> Clemens Ladisch wrote:
> > houghi wrote:
> > > Clemens Ladisch wrote:
> > > > "snd" works only for devices in /dev/snd/. However, the OSS (emulation)
> > > > devices are directly in /dev/, so try "lsof | grep -e snd -e dsp".
> > >
> > > See below, I am listening to music with MPD.
> > > alsamixer /dev/snd/controlC0
> > > xfce4-mix /dev/snd/controlC0
> >
> > What is "lsof | grep mpd" in this case?
>
> First I need sudo to get any information which can be seen here:
> http://houghi.eu/s/463O5YP There you can see the number playing.

mpd 4169 mpd 14u CHR 116,6 0t0 1249671 /dev/snd/pcmC0D0p
mpd 4169 mpd 9u CHR 116,9 0t0 1249713 /dev/snd/controlC0
mpd 4169 mpd mem CHR 116,6 1249671 /dev/snd/pcmC0D0p

These should by found by grepping for "snd".

> However when I play Lux, I do not see anything anywhere:
> http://houghi.eu/s/V0Z6EP

Well, I'd guess Lux does not use mpd to play its sounds.

What is the output of "lsof | grep /dev" when Lux is running?


Regards,
Clemens
From: Clemens Ladisch on 5 May 2010 03:57
houghi wrote:
> Clemens Ladisch wrote:
> > What is the output of "lsof | grep /dev" when Lux is running?

> xfce4-mix 18075 houghi 11u CHR 116,9 0t0 1249713 /dev/snd/controlC0
> xfce4-mix 18075 houghi 12u CHR 14,0 0t0 1249776 /dev/mixer
> alsamixer 22642 houghi 3u CHR 116,9 0t0 1249713 /dev/snd/controlC0

So Lux (and no other program) doesn't use any PCM device in /dev.

So, what files are used by Lux? Is it using some sound server?


Regards,
Clemens
From: J G Miller on 5 May 2010 06:56
Op Maandag, 3 mei, 2010 19:40:56 +0200, Houghi schreef:

> However when I play Lux

I have heard of mpd, but what is Lux?
(Do you have a URL for its home page, please?)

Incidentally mpd can be configured to send its audio
output to alsa dmix, pulseaudio, or esd.

See

<http://mpd.wikia.COM/wiki/Configuration>
From: J G Miller on 5 May 2010 09:00
Op Woensdag, 5 mei, 2010 13:36:04h +0200, Houghi schreef:

> http://sillysoft.net/lux/

Aha, play as in play the game, rather than play sounds through
some audio software.

> What I think is odd is that there is no clear one place to see what
> is using whatever causes sound to come out of my boxes, including any
> beeps.

Well perhaps the mpd.conf will give some clue as to which ALSA interface
is being used.

As for your complaint about there being "no one place" that is why
sound servers pulseaudio and esd were developped, so that sounds would
be going through one controlling piece of software which is intended
to be the only process locked on to your audio hardware device.

> Sure, it is using the alsa driver, but what connection to the soundcard?

Depends on whether it is using ALSA's own interface under /dev/snd/* or
via the deprecated OSS emulation via /dev/dsp etc.
From: J G Miller on 5 May 2010 10:16
Op Woensdag, 5 mei, 2010 15:43:26 +0200, Houghi schreef:

> audio_output {
> type "alsa"
> name "My ALSA Device"
> device "hw:0,0" # optional

So this is telling mpd to use the first audio hardware
device for which ALSA modules are loaded and thereby
assigned to sound-card-0.

You can manipulate the order via the alsa sound module
options with index=number in the modprobe.d configuration
directory

eg options module_for_sound_card index=0
options module_for_usb_audio_device index=1
etc

> mixer_device "default" # optional
> mixer_control "PCM" # optional
> mixer_index "0" # optional

So this is telling mpd to use the devices for card0, which
are found under /proc/asound/card0 which are mapped by
the device files under /dev/snd/pcmC0*

A second audio device would be /dev/snd/pcmC1*

> But still there should be some traces as to what is
> using the soundcard.

fuser on the appropriate device should tell you that,
if it indeed in use

fuser /dev/snd/*

/dev/snd/controlC0: 7708
/dev/snd/controlC1: 7708

where 7708 is in this case pulseaudio.

7708 1 0 10:14 ? 00:00:27 /usr/bin/pulseaudio --start
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