I inherited this from honey when he got a new Vaio.
There is a bug in the XFree86 4.1.x ct655xx driver, and it does not work on any machine I have tried. XFree86 4.0.3 or 4.2.0 or later should be ok.
One thing that wasn't obvious to me was that this machine will do 16 bit color, but you have to explicitly ask for this in your XF86 config file (see below). I also had to specify the chip set, which wasn't properly auto detected (this seems to be fixed in 4.0.3 and above).
If you can't get the audio to work, check the irq. OpenBSD wants it on 5, but the default seems to be 7.
Other resources on the web:
kernel config
dmesg
XF86Config
wdc
Always use 10 second timeout in wdcwait().
Try this if your disk fails to work after having been spun down.