I realize that the 3/DC isn't officially supported by the amr driver,  
so I tried to run it in I2O mode, but it didn't work at all there. It  
seems like if I leave the controller in the default "mass storage"  
mode, I get the non-working isp0 device. If I set it to I2O mode, I  
get a working isp0 that is able to see the drives and SCSI backplane,  
I guess because the iop didn't initialize. Is the 3/dc just an ugly  
duckling that nobody knows how to support yet?

ppb1 at pci0 dev 2 function 0: Intel S21152BA,S21154AE/BE PCI-PCI  
Bridge (rev. 0
x00)
pci4 at ppb1 bus 1
pci4: i/o space, memory space enabled
ppb2 at pci4 dev 0 function 0: Intel S21152BA,S21154AE/BE PCI-PCI  
Bridge (rev. 0
x00)
pci5 at ppb2 bus 2
pci5: i/o space, memory space enabled
amr0 at pci5 dev 0 function 0: AMI RAID <PERC 3/DC>
amr0: interrupting at ioapic1 pin 4 (irq 5)
amr0: firmware 197O, BIOS 3.35, 128MB RAM
ld0 at amr0 unit 0: RAID 1, optimal
ld0: 17278 MB, 8776 cyl, 64 head, 63 sec, 512 bytes/sect x 35385344  
sectors
isp0 at pci4 dev 1 function 0: QLogic Dual Channel Ultra-3 Wide SCSI HBA
isp0: interrupting at ioapic1 pin 5 (irq 5)
isp0: interrupt (ISR=4 SEMA=0) when not ready
isp0: interrupt (ISR=4 SEMA=0) when not ready
isp0: Polled Mailbox Command (0x8) Timeout
isp0: interrupt (ISR=4 SEMA=0) when not ready
isp0: interrupt (ISR=4 SEMA=0) when not ready
isp0: interrupt (ISR=4 SEMA=0) when not ready
isp0: interrupt (ISR=4 SEMA=0) when not ready
isp0: interrupt (ISR=4 SEMA=0) when not ready
isp0: Polled Mailbox Command (0x33) Timeout
isp0: failed to set tag age limit (8,8)
isp1 at pci0 dev 4 function 0: QLogic FC-AL and Fabric HBA
isp1: interrupting at ioapic1 pin 6 (irq 11)
isp1: bad execution throttle of 0- using 16
scsibus2 at isp1: 256 targets, 8 luns per target