help needed debugging SCSI bus problem

[Joan Picanyol]

[not subscribed to -scsi, if OT for stable please keep me in
Mail-Followup-To:]

Hi,

I can hang my system at will reading from my SCSI CD-RW. My hardware is
(excerpt from dmesg):

ahc0: <Adaptec 2940 Ultra2 SCSI adapter> port 0x1000-0x10ff mem
0xd0020000-0xd00
20fff irq 11 at device 14.0 on pci0
aic7890/91: Ultra2 Wide Channel A, SCSI Id=7, 32/253 SCBs
[...]
cd0 at ahc0 bus 0 target 2 lun 0
cd0: <YAMAHA CRW2100S 1.0G> Removable CD-ROM SCSI-2 device
cd0: 20.000MB/s transfers (20.000MHz, offset 7)
[...]
da0 at ahc0 bus 0 target 0 lun 0
da0: <SEAGATE ST318438LW 0003> Fixed Direct Access SCSI-3 device
da0: 80.000MB/s transfers (40.000MHz, offset 63, 16bit), Tagged Queueing Enabled
da0: 19001MB (38914049 512 byte sectors: 255H 63S/T 2422C)
[...]
da1 at ahc0 bus 0 target 6 lun 0
da1: <IBM DNES-309170W SA30> Fixed Direct Access SCSI-3 device
da1: 80.000MB/s transfers (40.000MHz, offset 31, 16bit), Tagged Queueing Enabled
da1: 8748MB (17916240 512 byte sectors: 255H 63S/T 1115C)

I can't paste the error messages, but I see a Dumping Card Ends. The
first error is an SCB timeout (0x25) on 0:6:0 (the IBM drive). I also
see other SCB timeout on 0:0:0 (the Seagate drive).

I can break into the debugger, but that's not much use (I'm always on
the keyboard interrupt handling routine) and I wouldn't know where to go
from there anyway. Would a panic be helpful (I'd would be painful to
setup but I would if needed)?

Oh, I'm running -stable from last week:
(12:26:50 <~>) 0 $ uname -v
FreeBSD 4.9-RC #1: Fri Oct  3 21:02:09 CEST 2003
joan at grummit.biaix.org:/fs/
tmp/mount/tmp/build/obj/fs/bulk/mount/FreeBSD/src/sys/GRUMMITD

I really don't know how to go on, any hints on what to do to help
debugging or what the source of the problem might be are most welcomed.

tks
-- 
pica