Crashes when accessing several devices

[Wessel Dankers]

Hi!

I'm experiencing problems with the Linux 2.0.31 kernel. I flicked all
aic7xxx switches to ON, because I thought my 2940AU would support it.
This 2940AU has a hard disk (Quantum Fireball TM2110S), a Pioneer
CD-ROM drive (DR-U12X) and an Iomega Zip drive attached to it.

The problem is, I now get kernel Oops's and (if I ignore these) errors
about interrupt code being called outside an interrupt, etc. if I access
two SCSI devices at the same time, for example:

cat /dev/scd0 >/dev/null &
find / -name hdjfhgsjhgdf

(My root is mounted on sda3.) The 2.1.59 version is even worse, it gets a
NULL-pointer-oops whenever I get data from the Zip-drive.

I'd be glad to supply additional information, I just don't know what is
relevant yet.

--
Wessel Dankers

(From dmesg)

aic7xxx: <Adaptec AHA-2940A Ultra SCSI host adapter> at PCI 9
aic7xxx: BIOS enabled, IO Port 0xe000, IO Mem 0xfb000000, IRQ 11, Revision C
aic7xxx: Single Channel, SCSI ID 7, 3/8 SCBs, QFull 8, QMask 0xf
scsi0 : Adaptec AHA274x/284x/294x (EISA/VLB/PCI-Fast SCSI) 4.1/3.2
scsi : 1 host.
scsi0: Scanning channel A for devices.
  Vendor: QUANTUM   Model: FIREBALL_TM2110S  Rev: 300X
  Type:   Direct-Access                      ANSI SCSI revision: 02
Detected scsi disk sda at scsi0, channel 0, id 0, lun 0
scsi0: Target 5, channel A, refusing synchronous negotiation; using asynchronous transfers.
  Vendor: IOMEGA    Model: ZIP 100           Rev: E.03
  Type:   Direct-Access                      ANSI SCSI revision: 02
Detected scsi removable disk sdb at scsi0, channel 0, id 5, lun 0
  Vendor: PIONEER   Model: CD-ROM DR-U12X    Rev: 1.06
  Type:   CD-ROM                             ANSI SCSI revision: 02
scsi : detected 2 SCSI disks total.
SCSI device sda: hdwr sector= 512 bytes. Sectors= 4124736 [2014 MB] [2.0 GB]
sdb : READ CAPACITY failed.
sdb : status = 1, message = 00, host = 0, driver = 28 
sdb : extended sense code = 2 
sdb : block size assumed to be 512 bytes, disk size 1GB.  
Partition check:
 sda: sda1 sda2 sda3
 sdb:scsidisk I/O error: dev 08:10, sector 0, absolute sector 0