I have also been running this nice piece of hardware on my gentoo box for some time now. After I found a kernel patch everything worked like a charm.
I have a RAID 1 setup with two 200GB disks.
05:0e.0 RAID bus controller: Promise Technology, Inc. Unknown device 8350
Subsystem: Promise Technology, Inc. Unknown device 0374
Flags: bus master, stepping, 66MHz, medium devsel, latency 96, IRQ 17
Memory at d4000000 (32-bit, non-prefetchable)
Expansion ROM at d3000000 [disabled]
Capabilities: [c0] Power Management version 2
Capabilities: [d0] Message Signalled Interrupts: 64bit+ Queue=0/1 Enable-
Capabilities: [e0] PCI-X non-bridge device
Mainbord is: nVidia Corporation CK804
Patches that I used: