I use ataraid (RAID-1) for my server, this is a ICH7 chipset (Atom 330). I'm also using gmirror at home.
When I got this machine a few months ago, I was actually rather suprised hardware RAID ever worked (Never had that happen!), I did some tests (Like yanking out drives, or simulating failure with dd command, and even hooking up a drive with bad sectors) and it gracefully recovered from all these scenarios...
Do you have other experiences phoenix?
btw.
You can view the source tree online here:
http://www.freebsd.org/cgi/cvsweb.cgi/src/
This includes the GENERIC files (sys/<arch>/conf/GENERIC).