I'm progressing with my mongrel 1.4.1 i586 setup, and just installed an
Adaptec AHA-1542CF to drive a Tandberg TD4120 tape and a Plextor RX-20TS
cdrom.  The card and devices probe and are identified correctly with no
apparent resource conflicts (addresses, irqs and drqs all clear comparing
dmesg w/ and w/o the card present), the cable is good (works on the linux
box that surrendered it), and no complaints from the Adaptec about
termination or other.  When I try to access either device I get a
"cd0(aha0:3:0): timed out" or "st0(aha0:2:0): timed out" message followed
by a "timed out AGAIN" a few seconds later and a long system hang.  I can
login on a second VT and continue (slowly), but a shutdown -h at that
point will hang after syncing.

The appropriate dmesg lines are as follows:
(bha probe): bha_cmd, cmd/data port empty 13
aha0: Model AHA-1542CF, firmware B.0
aha0: unlocking mailbox interface
aha0: async, parity
scsibus0 at aha0: 8 targets 8 luns per target
st0 at scsibus0 targ 2 lun 0 <TANDBERG, TD4100, =05:> SCSI2 1/sequential
removable
st0: drive empty
cd0 at scsibus0 targ 3 lun 0 <PLEXTOR, CD-ROM PX-20TS, 1.02> SCSI2 5/cdrom
removable

Any ideas what I'm missing?  For what its worth, this is a dual boot box
with FreeBSD 3.2, and their boot sequence goes into what appears to be a
terminal hang during the probe.  At least ours boots :-)

George E Sollish	Chief Engineer  	 Auto Gear Equipment
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			Project Manager		 The Payne Lake Project