>I *thought* that
>chip was supported by FreeBSD 3.0, but since it didn't work clearly I
>was confused.
>
>					- Bill

Support for these chips appeared in FreeBSD 3.0R (and in snapshot releases
before then):

ahc0: <Adaptec 2940 Ultra2 SCSI adapter> rev 0x00 int a irq 15 on pci0.9.0
ahc0: aic7890/91 Wide Channel A, SCSI Id=7, 16/255 SCBs
da0 at ahc0 bus 0 target 0 lun 0
da0: <SEAGATE ST34572W 0718> Fixed Direct Access SCSI-2 device 
da0: 40.0MB/s transfers (20.0MHz, offset 15, 16bit), Tagged Queueing Enabled
da0: 4340MB (8888924 512 byte sectors: 255H 63S/T 553C)
da1 at ahc0 bus 0 target 1 lun 0
da1: <QUANTUM XP34550S LYK8> Fixed Direct Access SCSI-2 device 
da1: 20.0MB/s transfers (20.0MHz, offset 31), Tagged Queueing Enabled
da1: 4341MB (8890760 512 byte sectors: 255H 63S/T 553C)

Ultra2 speeds work as well, but this machine doesn't have any of those
drives attached.

--
Justin