Comment 3 for bug 145857

Apologies for targeting the initial report to acpi-support.

Further information:

This occurs on a fresh install using http://cdimage.ubuntu.com/xubuntu/daily-live/20070923/gutsy-desktop-i386.iso. I reinstalled to minimize upgrade errors. The kernel update afterwards produces the same oops (and is what was used in the dmesg).

several of the /proc/acpi/ibm/ entries are missing which can cause monitoring applications to fail.
$ ls /proc/acpi/ibm/
driver hotkey light video

I tried patching the ubuntu source with thinkpad_acpi 0.16 (patches clean with offsets) but that still produces an oops.

I then tried vanilla 2.6.22.9 from kernel.org and patch with 0.16 and there is no oops and the missing entries are back.
$ ls /proc/acpi/ibm
beep driver fan led thermal volume
brightness ecdump hotkey light video

In both cases .config was produced by copying /boot/config-2.6.22-12-generic and then 'make oldconfig' to try and eliminate configuration differences as a variable. I followed the procedure in https://wiki.ubuntu.com/KernelCustomBuild.