Specifications

Previous versions of this HOWTO suggested checking the output of /dev/sndstat. This is no longer supported
in the 2.4 and later kernels.
Now you should be ready to play a simple sound file. Get hold of a sound sample file, and send it to the
sound device as a basic check of sound output, e.g.
% cat endoftheworld >/dev/dsp
% cat crash.au >/dev/audio
(Make sure you don't omit the ">" in the commands above).
Note that, in general, using cat is not the proper way to play audio files, it's just a quick check. You'll want
to get a proper sound player program (described later) that will do a better job.
If the above commands return "I/O error", you should look at the end of the kernel messages listed using the
"dmesg" command. It's likely that an error message is printed there. Very often the message is "Sound: DMA
(output) timed out − IRQ/DRQ config error?". The above message means that the driver didn't get the
expected interrupt from the sound card. In most cases it means that the IRQ or the DMA channel configured
to the driver doesn't work. The best way to get it working is to try with all possible DMAs and IRQs
supported by the device.
Another possible reason is that the device is not compatible with the device the driver is configured for. This
is almost certainly the case when a supposedly "SoundBlaster (Pro/16) compatible" sound card doesn't work
with the SoundBlaster driver. In this case you should try to find out the device your sound card is compatible
with (by posting to the comp.os.linux.hardware newsgroup, for example).
Some sample sound files can be obtained from
ftp://tsx−11.mit.edu/pub/linux/packages/sound/snd−data−0.1.tar.Z>
Now you can verify sound recording. If you have sound input capability, you can do a quick test of this using
commands such as the following:
# record 4 seconds of audio from microphone
% dd bs=8k count=4 </dev/audio >sample.au
4+0 records in
4+0 records out
# play back sound
% cat sample.au >/dev/audio
Obviously for this to work you need a microphone connected to the sound card and you should speak into it.
You may also need to obtain a mixer program to set the microphone as the input device and adjust the
recording gain level.
If these tests pass, you can be reasonably confident that the sound D/A and A/D hardware and software are
working. If you experience problems, refer to the next section of this document.
4.6. Troubleshooting
If you still encounter problems after following the instructions in the HOWTO, here are some things to check.
The checks are listed in increasing order of complexity. If a check fails, solve the problem before moving to
The Linux Sound HOWTO
4.6. Troubleshooting 12