I run NetBSD/i386 1.3.2 on a 400 MHz P-II with 512 MB ECC RAM and an
Adaptec 2940UW with two 9 GB Quantum Viking disks. dmesg(8) output
included at the end of this message.

The system has been running stably for over a year. Beginning a few weeks
ago the machine started sometimes rebooting itself and sometimes hanging,
in the latter case needing a toggle of the reset switch. The spontaneous 
reboots are fairly rare, most often the machine hangs (about once every
two or three days).

When the machine hangs, the kernel writes these messages on the console,
about two messages/second or so:


ahc0: target 0 synchronous at 20.0MHz, offset = 0x8
ahc0: target 0 synchronous at 20.0MHz, offset = 0x8
ahc0: target 0 synchronous at 20.0MHz, offset = 0x8
... and so on, for ever...


One one occasion a few days ago it said "target 1", but on most hangs it
writes the above message about "target 0". Targets 0 and 1 are identical
Quantum disks. The machine also has a CD-ROM at target 2 and a DLT tape
at target 3, but neither have been mentioned in the kernel messages on the
console during a hang.

Whether the machine spontaneously reboots or hangs there are no traces 
anywhere of what caused the problem. No crashdump and no entries in
syslog.

When I hit the reset switch the machine boots without problems. No disk
errors, no SCSI bus resets, no retries, nothing. The machine just boots as
if nothing had happened. I would have figured that if this was a hardware
problem that the problem would still be there when the machine
rebooted? (Especially since I never cycle the power). If it's a software
problem (ahc driver) why has the machine been running solid as a rock for
over a year?

Ideas anyone? Where do I start? Replace the controller?

Gunnar

--
Gunnar Helliesen   | Bergen IT Consult AS  | NetBSD/VAX on a uVAX II
Systems Consultant | Bergen, Norway        | '86 Jaguar Sovereign 4.2
gunnar@bitcon.no   | http://www.bitcon.no/ | '73 Mercedes 280 (240D)



Copyright (c) 1996, 1997, 1998
    The NetBSD Foundation, Inc.  All rights reserved.
Copyright (c) 1982, 1986, 1989, 1991, 1993
    The Regents of the University of California.  All rights reserved.

NetBSD 1.3.2 (LYONS) #0: Tue Mar 30 18:34:53 CEST 1999
    root@lyons.jag-lovers.org:/usr/src/sys/arch/i386/compile/LYONS
cpu0: family 6 model 5 step 1
cpu0: Intel Pentium Pro (686-class)
real mem  = 536477696
avail mem = 526512128
using 2822 buffers containing 26927104 bytes of memory
mainbus0 (root)
pci0 at mainbus0 bus 0: configuration mode 1
Intel product 0x7190 (host bridge, revision 0x02) at pci0 dev 0 function 0 
not configured
ppb0 at pci0 dev 1 function 0: Intel product 0x7191 (rev. 0x02)
pci1 at ppb0 bus 1
pcib0 at pci0 dev 7 function 0
pcib0: Intel 82371AB PCI-to-ISA Bridge (PIIX4) (rev. 0x02)
Intel 82371AB IDE controller (PIIX4) (IDE mass storage, interface 0x80,
revision 0x01) at pci0 dev 7 function 1 not configured
Intel 82371AB USB Host Controller (PIIX4) (USB serial bus, revision
0x01) at pci0 dev 7 function 2 not configured
Intel 82371AB Power Management Controller (PIIX4) (miscellaneous bridge,
revision 0x02) at pci0 dev 7 function 3 not configured
ahc0 at pci0 dev 8 function 0
ahc0: interrupting at irq 10
ahc0: aic7880 Wide Channel, SCSI Id=7, 16 SCBs
scsibus0 at ahc0 channel 0: 16 targets
ahc0: target 0 using 16Bit transfers
ahc0: target 0 synchronous at 20.0MHz, offset = 0x8
sd0 at scsibus0 targ 0 lun 0: <QUANTUM, VIKING II 9.1WLS, 3506> SCSI2
0/direct fixed
sd0: 8709MB, 8338 cyl, 10 head, 213 sec, 512 bytes/sect x 17836668 sectors
ahc0: target 1 using 16Bit transfers
ahc0: target 1 synchronous at 20.0MHz, offset = 0x8
sd1 at scsibus0 targ 1 lun 0: <QUANTUM, VIKING II 9.1WLS, 3506> SCSI2
0/direct fixed
sd1: 8709MB, 8338 cyl, 10 head, 213 sec, 512 bytes/sect x 17836668 sectors
ahc0: target 2 synchronous at 16.0MHz, offset = 0xf
cd0 at scsibus0 targ 2 lun 0: <PIONEER, CD-ROM DR-U06S, 1.05> SCSI2
5/cdrom removable
ahc0: target 3 synchronous at 10.0MHz, offset = 0xf
st0 at scsibus0 targ 3 lun 0: <Quantum, DLT4000, D473> SCSI2 1/sequential
removable
st0: drive empty
S3 product 0x8a01 (VGA display, revision 0x01) at pci0 dev 9 function 0
not configured
de0 at pci0 dev 10 function 0
de0: interrupting at irq 9
de0: DEC DE450-CA 21041 [10Mb/s] pass 1.1
de0: address 00:00:f8:30:fe:b9
isa0 at pcib0
com0 at isa0 port 0x3f8-0x3ff irq 4: ns16550a, working fifo
com1 at isa0 port 0x2f8-0x2ff irq 3: ns16550a, working fifo
lpt0 at isa0 port 0x378-0x37b irq 7
npx0 at isa0 port 0xf0-0xff: using exception 16
pc0 at isa0 port 0x60-0x6f irq 1: color
spkr0 at pc0 port 0x61
pc0: console
fdc0 at isa0 port 0x3f0-0x3f7 irq 6 drq 2
fd0 at fdc0 drive 0: 1.44MB, 80 cyl, 2 head, 18 sec
biomask 440 netmask 640 ttymask 6c2
boot device: sd0
root on sd0a dumps on sd0b
root file system type: ffs
de0: enabling BNC port