Still having problems with ahc

["Steve Shockley" <steve_(_dot_)_shockley_(_at_)_shockley_(_dot_)_net>]

Some time ago, I posted about some problems with the "new" ahc driver.  The
errors I'm getting on the console are:

ahc1: Data Parity Error has been reported via PERR#
ahc1: PCI error Interrupt at seqaddr = 0x7
ahc1: Signal System Error Detected
ahc1: Received a Master Abort
ahc1: Received a Target Abort
ahc1: Signaled a Target Abort

The seqaddr are usually 0x7, 0x8 or 0x9.

I originally suspected I might have a problem with an old drive, but since
then I've upgraded the controller, cable and drive.  From recent research,
it seems that PERR# means it's a PCI bus error, not a SCSI bus error.  These
messages didn't occur with the "old" ahc driver.  I haven't noticed any data
corruption or loss.

At the moment the machine's been up for four hours, and it's had the error
38 times.

The driver reports that the transfer rate is 20MHz, when in theory it should
be 40.  That's the least of my worries, though.

The machine is a Compaq Deskpro 2000 5233mmx.

dmesg:
OpenBSD 3.2-beta (GENERIC) #31: Wed Sep 11 17:06:58 MDT 2002
    deraadt_(_at_)_i386_(_dot_)_openbsd_(_dot_)_org:/usr/src/sys/arch/i386/compile/GENERIC
RTC BIOS diagnostic error 2
cpu0: F00F bug workaround installed
cpu0: Intel Pentium/MMX ("GenuineIntel" 586-class) 233 MHz
cpu0: FPU,V86,DE,PSE,TSC,MSR,MCE,CX8,MMX
real mem  = 100249600 (97900K)
avail mem = 87191552 (85148K)
using 1249 buffers containing 5115904 bytes (4996K) of memory
RTC BIOS diagnostic error 2
mainbus0 (root)
bios0 at mainbus0: AT/286+(ff) BIOS, date 12/10/98, BIOS32 rev. 0 @ 0xf1700
pcibios0 at bios0: rev. 2.1 @ 0xf1700/0x2100
pcibios0: PCI IRQ Routing Table rev. 1.0 @ 0xf1cc0/112 (5 entries)
pcibios0: PCI IRQ Routing Table rev. 1.0 @ 0xf7350/112 (5 entries)
pcibios0: PCI Interrupt Router at 000:07:0 ("VIA VT82C586 PCI-ISA" rev 0x00)
pcibios0: PCI bus #0 is the last bus
bios0: ROM list: 0xc0000/0x8000 0xc8000/0x6000
pci0 at mainbus0 bus 0: configuration mode 1 (bios)
pchb0 at pci0 dev 0 function 0 "VIA VT82C1595 Host-PCI" rev 0x06
dc0 at pci0 dev 2 function 0 "ADMtek AN983" rev 0x11: irq 11 address
00:04:5a:67:1c:35
ukphy0 at dc0 phy 1: Generic IEEE 802.3u media interface
ukphy0: OUI 0x000749, model 0x0001, rev. 1
xl0 at pci0 dev 3 function 0 "3Com 3c905 100Base-TX" rev 0x00: irq 11
address 00:60:97:db:45:68
nsphy0 at xl0 phy 24: DP83840 10/100 media interface, rev. 1
ahc1 at pci0 dev 4 function 0 "Adaptec AHA-2940U" rev 0x00: irq 11
ahc1: aic7880: Ultra Wide Channel A, SCSI Id=7, 16/255 SCBs
scsibus0 at ahc1: 16 targets
ahc1: target 0 synchronous at 20.0MHz, offset = 0x8
ahc1: target 0 using tagged queuing
sd0 at scsibus0 targ 0 lun 0: <SEAGATE, ST118273LW, 6246> SCSI2 0/direct
fixed
sd0: 17366MB, 7501 cyl, 20 head, 237 sec, 512 bytes/sec, 35566480 sec total
pcib0 at pci0 dev 7 function 0 "VIA VT82C586 PCI-ISA" rev 0x41
pciide0 at pci0 dev 7 function 1 "VIA VT82C571 IDE" rev 0x06: ATA33, channel
0 configured to compatibility, channel 1 configured to compatibility
uhci0 at pci0 dev 7 function 2 "VIA VT83C572 USB" rev 0x02: irq 11
usb0 at uhci0: USB revision 1.0
uhub0 at usb0
uhub0: vendor 0x0000 UHCI root hub, class 9/0, rev 1.00/1.00, addr 1
uhub0: 2 ports with 2 removable, self powered
"VIA VT82C586 Power Mgmt" rev 0x10 at pci0 dev 7 function 3 not configured
vga1 at pci0 dev 15 function 0 "S3 Trio64V2/DX" rev 0x16
wsdisplay0 at vga1: console (80x25, vt100 emulation)
wsdisplay0: screen 1-5 added (80x25, vt100 emulation)
isa0 at pcib0
isadma0 at isa0
pckbc0 at isa0 port 0x60/5
pckbd0 at pckbc0 (kbd slot)
pckbc0: using irq 1 for kbd slot
wskbd0 at pckbd0: console keyboard, using wsdisplay0
pmsi0 at pckbc0 (aux slot)
pckbc0: using irq 12 for aux slot
wsmouse0 at pmsi0 mux 0
pcppi0 at isa0 port 0x61
midi0 at pcppi0: <PC speaker>
sysbeep0 at pcppi0
lpt0 at isa0 port 0x378/4 irq 7
npx0 at isa0 port 0xf0/16: using exception 16
pccom0 at isa0 port 0x3f8/8 irq 4: ns16550a, 16 byte fifo
fdc0 at isa0 port 0x3f0/6 irq 6 drq 2
fd0 at fdc0 drive 0: 1.44MB 80 cyl, 2 head, 18 sec
biomask 840 netmask 840 ttymask 18c2
pctr: 586-class performance counters and user-level cycle counter enabled
dkcsum: sd0 matched BIOS disk 80
root on sd0a
rootdev=0x400 rrootdev=0xd00 rawdev=0xd02