Troubleshooting Sound Cards

If, after you configure the sound driver, the sound card does not produce sound when you play a sound file or an audio CD-ROM, try the following steps to diagnose and fix the problem:

Check to see whether or not the sound driver is included in the kernel. One way to check is to look at the contents of the /proc/devices file. The following is an example:
```
cat /proc/devices | more
Character devices:
  1 mem
  2 pty
  3 ttyp
  4 ttyS
  5 cua
  6 lp
  7 vcs
 10 misc
 13 input
 14 sound
 29 fb
 36 netlink
128 ptm
... lines deleted ...
```
The listing should show the character device 14 sound. If you don’t see this device, the kernel may not be configured properly or the sound driver module may not be loaded properly.
Verify that the sound driver detected the sound card when it was loaded. Type tail 100 /var/log/messages to look at the recent log messages; then check for a line reporting that the sound card was found. If the sound driver does not report the sound card, it’s possible that the sound card is not properly installed and configured.

First, make sure that the sound card works under DOS or Windows. Determine the I/O address, IRQ, and DMA channel, and reconfigure the kernel to include support for your sound card with the same parameters as under DOS.

If nothing works, you may want to read the latest Sound-HOWTO file. To read this file, point your Web browser to http://www.ibiblio.org/pub/Linux/docs/HOWTO/Sound-HOWTO. You can also find documentation for specific sound drivers in the /usr/src/linux-2.4/Documentation/sound directory. Note that this directory exists only if you have installed the Linux source code (see Chap- ter 21 for more information).

Insider Insight

If you still cannot get the sound card to work under Linux, you may want to post a news item to one of the comp.os.linux newsgroups. Chapter 16 discusses how to connect to the Internet and access the newsgroups. You might also consider purchasing the low-cost ($20) commercial version of the Open Sound System (OSS) driver from 4Front Technologies (http://www.opensound.com/). The commercial OSS driver supports more sounds cards (in particular, sound cards with proprietary programming information) than the OSS driver included with the Linux kernel.