Welcome to LQ!
Which kernel are you running? In a terminal issue "uname -a" and
post the output. Please use code tags in your post, so we can more
easily read your output. Put [*code] without the * (asterisk) before
your output, and [*/code] without the * after your output.
There is no need to compile ALSA from source for Slackware anymore.
It is included in Slackware-11.0.
Some tentative thoughts, after reading through this ALSA
I don't see these "snd-opl3" entries on the ALSA web page. Are you
certain you need that for your soundcard? If not, you should issue
"modprobe -r snd-opl3-synth" and "modprobe -r snd-opl3-lib" to remove
them from your system.
Actually, you might not need all the sound modules you have loaded,
and your system doesn't seem to see the ISA soundcard when looking at
your lspci output. I've never used an ISA device in Linux, so maybe
it doesn't show up in "lspci" -- list PCI devices.
If you didn't configure anything to load those modules when you boot,
please reboot your computer and then open a terminal and as root issue:
If that finds you soundcard, you're probably in business. If not, then
we've got to find out why the kernel hasn't located it. Afterwards, issue:
modprobe snd-sb16;modprobe snd-pcm-oss;modprobe snd-mixer-oss;modprobe snd-seq-oss
per the ALSA instructions. Then issue "alsamixer" and unmute everything
with the M key, then turn up the volumes on at least Master and PCM. Then
hit ESC to close the ALSA mixer, then issue "alsactl store" to save settings.
Test if you have sound by issuing:
cat /dev/urandom >/dev/dsp
and be ready to hit Ctrl+C because if you do have sound, there's going to be
some nasty noise coming from your speakers.
Post back if you have sound, and your new "lsmod" output please.