Enable ACPI on kernel-image-2.4.22?

[Damien Solley <dsolley@student.usyd.edu.au>]

Hi
How do I enable ACPI with the debian kernel package
kernel-image-2.4.22-1-686 (in Sarge)? I see that ACPI has been disabled
by default with this kernel (closing bugs #210512,  #210563, #210727,
#211594). However, when I boot with "acpi=on" as a kernel argument, I
get no ACPI.
Dmesg shows "ACPI: Interpreter disabled."
And, predictably, trying to modprobe battery, thermal or ac modules all
complain "No such device". 
Note that booting with a kernel.org 2.4.22 provides me with working
ACPI, including ac, battery, thermal. With this standard kernel I get
"ACPI: Interpreter enabled" and lots of normal ACPI dmesg output.

Some relevant output follows:

$ uname -a 
Linux laptop-sd.ucc.usyd.edu.au 2.4.22-1-686 #6 Sat Oct 4 14:09:08 EST
2003 i686 GNU/Linux
$ dmesg |grep -i acpi
ACPI: have wakeup address 0xc0001000
Kernel command line: hda=ide-scsi ro vga=773  root=/dev/hdc3 acpi=on
ACPI: Subsystem revision 20030813
ACPI: Interpreter disabled.
PCI: ACPI tables contain no PCI IRQ routing entries


Relevant GRUB entry:
"title Debian Linux (kernel 2.4.22)
root (hd0,0)
kernel /vmlinuz-2.4.22-1-686  hda=ide-scsi ro vga=773  root=/dev/hdc3 ac
pi=on 1
initrd /initrd.img-2.4.22-1-686"

Regards
Damien