The Dell PV132T tape library's changer apparently used to expect the
SMS_DBD bit to be _set_ in Mode Sense requests, or it just sulks, see
link [1] and dmesg excerpt [2] below. This was incorrect behaviour on
its part, AFAIK.

So, I began to imagine some sort of a SDEV_MSDBDON SCSI quirk, but
turns out it's fixed by latest firmware. Upgrading firmware of the
tape library to the recently released 310D (Dell support file:
R121419.EXE of 2006-06-20) fixes it [3].

Probably not worth worrying about to the extent of adding a quirk for
now-obsolete firmware, but figured I should report it as someone else
might well be trying to use the device with OpenBSD: OpenBSD after all
is quite a likely choice for a trusted backup server.

[1] http://www.webservertalk.com/archive...-2-126606.html

[2] Dell PV132T library firmware 227D doesn't work (dmesg excerpt)
....
ch0 at scsibus1 targ 0 lun 0: <DELL, PV-132T, 227D> SCSI2 8/changer \
removable
....
ch0(ahc0:0:0): Check Condition (error 0x70) on opcode 0x1a
SENSE KEY: Illegal Request
ASC/ASCQ: Illegal Field in CDB
SKSV: Error in CDB, Offset 1, bit 3
ch0(ahc0:0:0): Check Condition (error 0x70) on opcode 0x5a
SENSE KEY: Illegal Request
ASC/ASCQ: Invalid Command Operation Code
ch0: could not sense element address page
ch0: offline


[3] Dell PV132T library firmware 310D works (dmesg excerpt)
....
ch0 at scsibus1 targ 0 lun 0: <DELL, PV-132T, 310D> SCSI2 8/changer \
removable
....
ch0: 22 slots, 1 drive, 1 picker, 1 portal