After installing Slackware 14.1 on a new machine, I got unexpected output
when tried to run rexima interactive mixer (by the way, it's in
extra section of Slackware packages, so search might silently skip it, just
slackpkg install rexima to install it). The output was:
$ rexima rexima: couldn't open mixer device.
Examining with strace gave such results:
$ strace -e trace=open rexima open("/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3 open("/lib64/libncurses.so.5", O_RDONLY|O_CLOEXEC) = 3 open("/lib64/libc.so.6", O_RDONLY|O_CLOEXEC) = 3 open("/lib64/libdl.so.2", O_RDONLY|O_CLOEXEC) = 3 open("/dev/mixer", O_RDWR) = -1 ENOENT (No such file or directory) rexima: couldn't open mixer device. +++ exited with 1 +++
$ ls /dev/mixer /bin/ls: cannot access /dev/mixer: No such file or directory
No wonder it couldn't open mixer device...
Searching for possible solution revealed this forum post (excerpt):
/dev/mixer and /dev/dsp are legacies from the OSS days, as I understand it.. You'll only be able to use them if you've got those emulation modules loaded and working.
Don't know enough about sound subsystem, but those modules were definitely absent on my machine:
# lsmod | grep oss
So I installed
snd_mixer_oss (got its name from that forum post):
# modprobe snd_mixer_oss # ls /dev/mixer /dev/mixer
rexima works well now. Well, until reboot. For persistance I created
$ cat /etc/modprobe.d/sound-oss.conf # enable /dev/mixer device to be able to use rexima install snd_mixer_oss