Well, on my SparcClassic reloading the modules is not necessary at all - audioctl works out of the box. But could you tell me which modules exactly you are using (is alsa involved) for the cs4231? I am facing the same problems as you did, on a SunBlade 1000 (UltraSparc III, 2.6.8-sparc64) and I cant't actually find a way to get audio running on Linux - on Solaris 10 the onboard audio works pretty good, and I don't want to missit on Linux.
Honestly, I'm just about 20 hours old with Debian on ultrasparc. I'm really new. ALSA? I don't know if it's involved with cs4231. When I lsmod, it just shows 2 devices, audio and cs4231. I'm afraid, I won't be able to help you out. Thanks,
Neil