How Can I Only Make a Specific Screen Sleep?

Question

I use my laptop with multiscreen: laptop screen on one side, my TV displaying my media center (Kodi) on the other side. Problem, when I use my media center to watch a movie, the laptop screen never switch to sleep mode.

I'm looking for a command to sleep the laptop screen, but ONLY this screen, and go out of this mode by using the touchpad. I was thinking to use xrandr, but it seems I can only deactivate (with option --off) the screen, and not just sleep it.

Any idea that would help?

Accepted Answer

Toggle- dim a specific screen

The command to dim the screen (not switch off, but not "sleep" either) would be:

xrandr --output $monitor --brightness 0

You can however easily toggle- dim the targeted screen with a keyboard shortcut. Add the script below to a shortcut:

#!/bin/bash
# --- set your monitor below
monitor=VGA-0
# ---
if [ -z "$(xrandr --verbose | grep 'Brightness: 0.0')" ]; then
  xrandr --output $monitor --brightness 0
else
  xrandr --output $monitor --brightness 1
fi

To use

Copy the script into an empty file, save it as dim_screen.sh, and make it executable
In the head of the script, set the name of your targeted screen. Run the command xrandr to find out if you don't know.
Add it to a shortut key: Choose: System Settings > "Keyboard" > "Shortcuts" > "Custom Shortcuts". Click the "+" and add the command:

    /path/to/dim_screen.sh

Must Read

Explanation

The test:

[ -z "$(xrandr --verbose | grep 'Brightness: 0.0')" ]

will see if the command xrandr --verbose | grep 'Brightness: 0.0' has an output, in other words, if your screen is dimmed. If so, it will set the targeted screen to "normal" brightness (1.0):

xrandr --output $monitor --brightness 1

...else it will dim the screen with the command:

xrandr --output $monitor --brightness 0

Note

It seems impossible to only put a specific screen to sleep. This answer is written, assuming you want the screen, dimmed, but switching it off, including the black out of both screens, is too much a fuzz.

Answer 2

From How do I turn off the backlight but leave the LCD on?:

$ sudo -i
# Turn backlight off
echo 4 > /sys/class/backlight/intel_backlight/bl_power
# Turn backlight on
echo 0 > /sys/class/backlight/intel_backlight/bl_power
exit
$

I've just tried this and it works fine on my laptop.