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After installing Ubuntu on my ThinkPad T510, the GDM screen and GNOME session would always start at 100% brightness.

I quickly found out, that this can be controlled via gnome-power-preferences, but I'd like to have GDM and the GNOME session follow the global backlight setting (ie., when I set it during POST, GRUB, GDM, a GNOME session, or on a TTY, I expect it not to automatically change).

So, how can I make gnome-power-manager stop automatically changing my backlight level?

htorque
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1 Answers1

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It seems this can only be disabled by editing a gconf setting using gconf-editor or the command line tool gconftool-2 (easier). As GDM is run by a special user (gdm), you got to disable it for the desktop user and that special user:

Run the following from a gnome-terminal:

gconftool-2 --set --type boolean  "/apps/gnome-power-manager/backlight/enable" false

This will deactivate the backlight control for your user. Now type:

sudo -u gdm gconftool-2 --set --type boolean  "/apps/gnome-power-manager/backlight/enable" false

This will deactivate the backlight control for the user that controls the GDM screen.

You should now no longer see automatic backlight level changes.

In Ubuntu 11.10 Oneiric Ocelot this changed to:

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

Still not sure how to disable it for the login screen.

htorque
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    This command for ubuntu oneiric doesn't work.. can you correct it? – fain182 Oct 15 '11 at 08:54
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    I think is `gsettings set org.gnome.settings-daemon.plugins.power idle-dim-battery false` – fain182 Oct 15 '11 at 10:13
  • Is the section about GDM's user still accurate (given that we're not on LightDM)? Edit: I see the revised section below now. – Oli Nov 02 '11 at 10:36
  • Not sure about GDM in 11.10. This should be tested with a fresh install, but I'm low on disk space on the device where I saw this happening. – htorque Nov 02 '11 at 16:57
  • Even after running the 11.10 commands here, it keeps maxing out the backlight every few seconds if I reduce it (on AC). Any idea why? – l0b0 Dec 03 '11 at 00:35
  • @l0b0 If you are using the binary Nvidia driver, then that's likely the culprit. Try the solutions to [this question](http://askubuntu.com/questions/74376/brightness-control-problem-on-sony-vaio-with-nvidia-gt-320m). – htorque Dec 03 '11 at 09:34
  • @htorque: Nope, don't need any proprietary driver for the Samsung 900X3A. – l0b0 Dec 04 '11 at 22:08