Screen brightness increases by itself

[Giovanni Pardini]

If I decrease the screen brightness using the Fn-F5 key to the lowest level, after a few seconds of inactivity (without touching the keyboard nor the touchpad) the screen brightness goes up automatically to a medium level.
Then, as soon as I move the pointer, the brightness is increased to the maximum level.

From this point on, the screen brighness alternates automatically between medium/maximum level. That is, it decreases when idle, and increases when using the keyboard or mouse.

The expected behaviour is that brightness does not change by itself once set using the Fn keys.

This bug happens when on battery power.
I didn't try on AC power.

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: gnome-power-manager 3.2.1-2
ProcVersionSignature: Ubuntu 3.2.0-8.15-generic 3.2.0
Uname: Linux 3.2.0-8-generic x86_64
ApportVersion: 1.90-0ubuntu2
Architecture: amd64
Date: Sat Jan 14 21:44:39 2012
ProcEnviron:
 PATH=(custom, no user)
 LANG=it_IT.UTF-8
 SHELL=/bin/bash
SourcePackage: gnome-power-manager
UpgradeStatus: No upgrade log present (probably fresh install)

[Giovanni Pardini (gio.pardini)]

I found a workaround, which is to disable automatic dimming when idle, using the following command:

gsettings set org.gnome.settings-daemon.plugins.power idle-dim-battery false

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[tacka (tacuszka)]

Same thing here (eee x101).

[Manaf Yusuf (manaf-yousif)]

[SOLVED workaround]

using function keys to decrease the brightness works temporarily but once you open the birghtness & lock settings or the screen dims then moving the pointer increases to fullest.

It looks like the fuction key settings is not linked to the birghtness & lock settings when I decrease/increase the brightness the slider does not move and stays constant.

The best way is to decrease brightness from the slider in the "brightness & lock" settings

see screenshot