Jtdcftul

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.

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:

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

Turn screen of when inactive for: Never

I just ran sudo xset s off from a terminal and it may be fixed.

There is a checkbox in "System Settings" -> "Brightness And Lock" screen whose label is "Dim screen to save power". You must uncheck it.

The answer provided by chaos is very informative. However, even after following those instructions, I still had this problem intermittently. There is some sort of background process or settings manager that keeps resetting the screensaver, no matter what I do.

I've found a brute-force solution. Just add a line to your crontab to turn off DPMS and the screensaver every single minute. Ugly, but effective.

Type this at the terminal

crontab -e

And then add the following lines at the bottom of the file

* * * * * DISPLAY=:0.0 xset -dpms

* * * * * DISPLAY=:0.0 xset s off

You can also comment these lines out by prepending a '#' when you want to re-enable the screensaver.

In Ubuntu 12.10, If you have KDE as the windowing manager:

Disable monitor dimming and energy saving tool:

1. Click System Settings.


2. In the "Hardware" tab choose "Power Management"


3. Choose "Energy saving settings"

there are two checkboxes: Dim Display and Screen Energy Saving. Make sure those are unchecked.

In Ubuntu 12.10, If you are using the default unity windowing manager:

1. Click System Settings.


2. In the "Hardware" tab choose "Power"


3. Click the link: "Brightness settings"


4. There is a dropdown called: "Turn screen off when inactive for"

Set the dropdown to 'Never'.