To test my new OS's gaming capabilities, I d/led Return to Castle Wolfenstein Multiplayer Demo, and the sound isn't working. When I run it in console, part of the output is:

------- sound initialization -------
/dev/dsp: Input/output error
Could not mmap /dev/dsp
------------------------------------

I'm using ALSA on RedHat 8.0. My sound card is a TB Santa Cruz, for which I use the snd-cs46xx module. I checked and I think the permissions on /dev/dsp are correct. My fellow gamers, how can I fix this?

Thanks for any clues.

I happened to stumble across this post and noticed it had never been answered. The solution to this problem is to load the snd-cs46xx module with the mmap_valid=x option, setting x to a valid integer value between 1 and 8, like so:

modprobe snd-cs46xx mmap_valid=1

This is the method to do it manually. What you do to make it work automatically will vary depending on how you have ALSA set up. With the method outlined by ALSA instructions, you need this on an options line in your modules.conf file after your sound card alias. For example:

# ALSA portion
alias char-major-116 snd
alias snd-card-0 snd-cs46xx
options mmap_valid=1

Any other options you need should go on the same options line separated by a space for each option.

What I did:

The game needs access to some sound-device -->
I do
ls -la /dev/dsp*
in the console to see where /dev/dsp points to. For me that is /dev/sound/dsp or whatever. So the sound-devices the game is looking for are in /dev/sound. As /dev/sound/dsp does not work, I try something else, namely /dev/sound/adsp, and luckilliy this works :-)

To change the sound-device for the game (quake3 or enemy territory or whatever similar)
just start the game, then open the console with the tilde-key (for me <Alt Gr><~>, then <space>). Here you have to enter

snddevice "/dev/sound/adsp"

This works for me and you don't have to change any rights or whatever. Just restart the game and sound should be on.