I figured out a solution that works indefinitely, at least till an
update comes along anyway. Go to applications>settings>Xfce 4 Settings
Manager>Power Management and  all settings for monitor and brightness to
never. So far this has worked, as long as I don't try to adjust the
brightness because that would trigger our little problem again which I don't
wanna do. So until there is a fix this works fine, actually I'll keep my
settings this way just in case. Hope this helps.

On Tue, Nov 3, 2009 at 4:04 AM, Samuel G. I. <email address hidden> wrote:

> *** This bug is a duplicate of bug 415023 ***
>    https://bugs.launchpad.net/bugs/415023
>
> ** Also affects: gnome-power-manager (Arch Linux)
>   Importance: Undecided
>       Status: New
>
> --
> brightness autonomously toggles after increasing brightness
> https://bugs.launchpad.net/bugs/460062
> You received this bug notification because you are a direct subscriber
> of a duplicate bug (via bug 415023).
>
> Status in “gnome-power-manager” package in Ubuntu: New
> Status in “gnome-power-manager” package in Arch Linux: New
>
> Bug description:
> Binary package hint: gnome-power-manager
>
> This bug is very similar to bug 456057, but there are a couple of critical
> differences that I think warrant a new bug:
> a) The user in bug 4567057 found that he couldn't change brightness without
> gnome-power-manager running. I can on my laptop.
> b) Bug 456057 could apparently be reproduced without gnome-power-manager
> (i.e. xubuntu/xfce), whereas I've found killing gnome-power-manager actively
> solves my problem.
>
> On to my bug:
>
> I have an MSI Wind U100 laptop (model MS-N011 according to the sticker on
> the bottom). The laptop has hot-keys to control the backlight brightness
> (Fn+F4/F5). If I lower the brightness this way, everything is OK. If I raise
> the brightness, something autonomously keeps toggling the brightness up/down
> one level (or some fairly small amount). I am running a standard Gnome
> desktop in Karmic UNR (dist-upgrade'd from Jaunty UNR). Things I have
> observed:
>
> 1) The toggling starts soon after the gdm login screen starts after reboot
> 2) The toggling starts when I increase the brightness using the keyboard
> 3) The toggling starts if I execute .
> /usr/share/acpi-support/key-constants; sudo acpi_fakekey $KEY_BRIGHTNESSUP"
> 4) The toggling lasts while (many seconds;maybe 10-30) and usually stops on
> its own. Just occasionally it doesn't ever stop on it's own.
> 5) The toggling stops within a few seconds if I VT-switch to a console
> 6) The toggling stops immediately if I "kill `pidof gnome-power-manager`"
> 7) The toggling doesn't start if I adjust the brightness using the keyboard
> whilst in a VT console
> 8) The toggling doesn't start if I execute the commands from (3) above in a
> VT console (and those commands have no effect)
> 9) The toggling doesn't start if I log into a "Gnome failsafe" session.
> 10) The toggling doesn't start if I log into an "Xterm" session.
> 11) I can adjust the brightness using the keyboard after having killed
> gnome-power-manager.
> 12) If I restart gnome-power-manager, the brightness immediately shoots up
> to full, and starts toggling between max and max-1.
>
> I have gnome-power-manager package 2.28.1-0ubuntu1.
>