Having just installed Debian on a CF-27, I can reassure you that the sound works perfectly using OSS under 2.4.
The chip is an AD1848 (ISA device). You may have trouble getting it working if you don't go into the bios (F2 on startup) and find the setting relating to sound; by default this is set to "Auto" IIRC, set this to enable, and you will see it "hard wires" the values for IO, IRQ, etc. You shouldn't need to change them though, just set it to enable.
I just ran sndconfig and it did the job fine for OSS; personally I've never had any success in getting alsaconf to detect the card on any machine!
There is an ALSA driver for the card, I've not bothered to try it yet.
BTW, this is a useful page for linux on the CF-27
That's google's cache, I couldn't get the original page last time I tried.