[alsa-devel] can not access the alsa driver

Joachim Foerster mls.JOFT at gmx.de
Sun Jan 6 11:29:44 CET 2008


On Sat, 2008-01-05 at 22:42 +0800, Ning Zhang wrote:
> ( I did not found /dev/snd  or /dev/dsp )
> But when I run the application, I got these errors:
> # /tmp/pcm_play_arm_s default
> ALSA lib pcm.c:2145:(snd_pcm_open_noupdate) Unknown PCM default
> Playback open error: No such file or directory

Well, I think, the /dev/snd/* devices files have to exist. Do you use
udevd? If not, I guess you have to create these files manually - or by
using the snddevices script in alsa-driver package.
If you use udevd, then - perhaps - your are missing some rules files
(/etc/udev/rules.d). Have a look at your Linux distributions rules files
of your host PC.

> Here are my questions:
> 1, When we install the alsa-lib, we can get some libs, besides those, do we
> also get some config files according to the local linux environment and
> alsa-lib will use these config files to access the real driver? If that, how
> can I install the alsa-lib to a embedded platform directly or what config
> files should I port to embedded platform?
> 2, Must I edit ~/.asoundrc and /etc/alsa/alsa.conf ? In my situation, what
> should I do ? Is somebody so kind can give me a simple template?

I cannot really say something about your questions - I hadn't to create
any special config. files, when I started using my own driver (for a
PPC405 based board (ML403)). I just cross-compiled and installed
alsa-lib and alsa-tools (to have aplay and arecord).


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