Ubuntu – Ubuntu 12.10 “Turn screen off when inactive for: Never” still turns off

12.10displaypower-managementscreen

After a fresh install of Ubuntu 12.10, my screen still goes off after about ten minutes. I've been to the Brightness and Lock control panel. The Turn screen off when inactive for: setting is set to Never.

I've been through the dconf editor searching for power, screen, and idle changing parameters. This doesn't seem to have any effect on the display timeout.

Here's one more interesting thing, the screen doesn't go off, it just goes black. The back lighting is still on, and all the pixels are black.

When it goes black, it does a very pleasant quick dim to black.
Similarly, it quickly un-dim's after a key press, mouse movement, or mouse click.

Best Answer

There are multiple different layers, that influence the behavior of the monitor. To completely disable any suspension of the monitor you need to disable it in every of those layers:

1. layer: virtual consoles

Sets the interval of inactivity, in minutes, after which the screen will be automatically blanked:

setterm -blank 0

Sets the VESA powerdown interval in minutes:

setterm -powerdown 0

2. layer: X

Turn the screen saver function off. The s option lets you set the screen saver parameters.

xset s off

Disable DPMS if enabled:

xset -dpms

To find out which values are set type xset -q in a terminal. A part of the output should look like this:

Screen Saver:
  prefer blanking:  yes    allow exposures:  yes
  timeout:  0    cycle:  0

and this:

DPMS (Energy Star):
  Standby: 0    Suspend: 0    Off: 0
  DPMS is Disabled

3. layer: Last but not least; the application layer (XScreenSaver)

xscreensaver-demo

Choose Disable Screen Saver:

xscreensaver

And deactivate screensaver in System Settings -> Brightness & Lock (depends on your desktop environment):

Turn screen of when inactive for: Never

Brightness & Lock

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