Re: [gentoo-user] Re: Sound card is only usable by one application at a time

[Jesús Guerrero]

On Fri, 04 Dec 2009 00:36:36 +0200, Nikos Chantziaras <realnc@×××××.de>
wrote:
> On 12/03/2009 11:23 PM, Yoav Luft wrote:
>> Hi,
>> On my dell Vostro 1520, with intel hda ICH9 82801I sound card
>> (xSTAC92HD71B3, according to /proc/asound/card0/codec), only one
>> application can access the sound card at a time. This probably means
>> that applications access the hardware, and not some software mixer. I
>> tried to follow information in the alsa wiki
>>
(http://www.alsa-project.org/alsa-doc/alsa-lib/pcm_plugins.html#pcm_plugins_dmix)
>> for setting manually dmix, but couldn't configure anything working. I
>> could find any good documentation (and I don't have plenty of time to
>> dig in it, it's the middle of the semester). Does anyone can help on
>> the topic?
>
> I think all you need to do is to put the "alsasound" service in your
> default runlevel.
>
>    rc-update add alsasound default
>
> At least that's what I remember doing when I tried ALSA a few months
> ago.  You might need to reboot though so that the card is freed first.

All alsasound does is to save and restore mixer settings, so you don't
have to modify them by hand each time you reboot. 

There are a number of problems with dmix in alsa, it's one of the reasons
why people keep inventing stuff like pulseaudio to work around these
issues, when they should be fixing the problem itself, which is in alsa. I
for one, use the ca0106 driver for an audigy card. dmix here works ok...
until you play a 5.1 stream. When the surround is enabled then dmix doesn't
work, and I can't play anything else. When I am in regular stereo mode I
can play as many streams as I want without a problem.

This is well known, reported, and it has hit a lot of people. But
unfortunately, there's no fix yet.

@Yoav Luft, I don't know if this is the same problem, maybe it doesn't
relate at all. You should start by checking that there's no pulseaudio or
something like that monopolizing the alsa output, because maybe the problem
is not alsa itself. But, if alsa is running alone, I'd start by checking
the alsa bug tracker and see if there's someone that has the same card/uses
the same driver and has the same problem.

-- 
Jesús Guerrero