ACPI breakage

Hi,

On trying to boot a recent CURRENT kernel on one of my machines (i386 kernel,
Pentium III (Katmai) 500 MHz CPU, Abit BH6 motherboard), I get a panic:
...
pcib1: <PCI-PCI bridge> at device 1.0 on pci0
pci1: <ACPI PCI bus> on pcib1
pcib0: slot 1 INTA is routed to irq 12
pcib1: slot 0 INTA is routed to irq 12

Fatal trap 12: page fault while in kernel mode
fault virtual address = 0x15

(Unfortunately this was transcribed by hand and does not show bootverbose
output or a backtrace. I can't provide these right now.)

With an identical source tree, I *don't* get a panic on another system
(amd64 kernel, Athlon 64 3000+ CPU, ASUS K8V Deluxe motherboard ver. 1005)

Reverting to sys/dev/acpica/acpi_ec.c revision 1.47 makes the panic disappear.
In case it's useful, this is what the dmesg looks like with the old
version of acpi_ec.c:
...
pcib1: <PCI-PCI bridge> at device 1.0 on pci0
pci1: <PCI bus> on pcib1
pcib0: slot 1 INTA is routed to irq 12
pcib1: slot 0 INTA is routed to irq 12
pci1: <display, VGA> at device 0.0 (no driver attached)
isab0: <PCI-ISA bridge> at device 7.0 on pci0
isa0: <ISA bus> on isab0
...

The only interesting difference I can see here is that pci1 has gone
from being a "PCI bus" with rev. 1.47 to an "ACPI PCI bus" with rev. 1.49.
pci0 always shows up as an "ACPI PCI bus".

Suggestions? I would try to debug this a little further myself, but as
the machine in question acts as my dialup gateway, it's rather inconvenient
to reboot it often or take it offline.


Tim