Brightness buttons very slow

Binary package hint: acpi

1) 9.10 karmic
2) acpi 1.4-2 ** I am not sure acpi is the right package **
3) I expected intensity of the display backlight to change at least within a second when pressing XF86MonBrightnessDown and XF86MonBrightnessUp keys.
4) Brightness changes, but there is a huge delay between each step. In jaunty changes have a small delay, and there were no or very short lag when changing in multiple steps.

When pressing BrightnessDown intensity lowers after a second, it then takes another second for the osd to display/update. If I press multiple times it takes one + one second for each step. The same happens with BrightnessUp. Times are estimates.

I had a similar experience in hardy and intrepid, although that got corrected somewhere along the way, and worked fine in jaunty. See bug #286102. (This bug is not a dup of the old bug, although they are similar)

My system is a laptop:
Hewlett-Packard
HP Pavilion dv2000 (RN081EA#UUW)
F.34

ProblemType: Bug
Architecture: amd64
Date: Mon Oct 12 20:33:21 2009
DistroRelease: Ubuntu 9.10
NonfreeKernelModules: nvidia
Package: acpi 1.4-2
ProcEnviron:
 LANG=sv_SE.UTF-8
 SHELL=/bin/bash
ProcVersionSignature: Ubuntu 2.6.31-13.44-generic
SourcePackage: acpi
Uname: Linux 2.6.31-13-generic x86_64