On my ThinkPad W520 laptop, after a short period of inactivity (eg. no mouse movement) on battery, the screen dims for power saving. When I move the mouse (ie. , the screen lights back up, but not at the same level (darker) than it was before.

I've seen some code a while ago with X managing the dimness (?) but can't remember where it was. Maybe I can configure something in X or somehow do something with it?

Who is responsible for lighting the screen up when the mouse moves? How do I make it go back to its original setting when it becomes active again?

  • The question wasn't about turning off inactivity dimming, but how to gain back the same light intensity after moving the mouse, coming back from inactivity. – jonallard Apr 27 '12 at 18:16

For 11.04 and earlier:

This is done (screen dimming) as a part of power savings while on battery power.

You can change this in "Power Management" in System settings.

Unselect "Dim display when idle" on the On Battery Power tab.

Dim display

For additional information see


For 11.10 and newer:

It is a settings in System Settings > Brightness and Lock

Open System Settings and goto Brightness and Lock icon

Where to find Brightness and Lock

Yours might be looking like

One minute screen lock

Change the Turn screen off when inactive for: to Never

Never screen lock

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