Linux: Xrandr failed to get size of gamma for output - you can do that

Xrandr failed to get size of gamma for output is a bug on Linux that can be easily fixed. You can find out more about this in the following practical tip.

Xrandr failed to get size of gamma for output on Linux - that's the reason

This error usually occurs when, for example, you want to assign a new profile with a changed screen resolution to a screen.

• The new profile is created with "xrandr --newmode".
• A common mistake here is to prepend "sudo". This creates the profile with administrative rights.
• This leads to the error message "Xrandr failed to get size of gamma for output".

Change screen resolution with Xrandr on Linux

Add a new resolution profile to your screen as follows.

1. First calculate the settings required later with the command cvt 1200 1000 60.
2. Here a profile with the resolution 1200x1000 and 60 Hz is calculated. The output should look something like this: # 1200x1000 59.91 Hz (CVT) hsync: 62.19 kHz; pclk: 99.50 MHz Modeline "1200x1000_60.00" 99.50 1200 1280 1400 1600 1000 1003 1013 1038 -hsync + vsync.
3. Now enter the second line of the output in the next command with which you create the profile: xrandr --newmode "1200_1000_60" 99.50 1200 1280 1400 1600 1000 1003 1013 1038 -hsync + vsync.
4. Then add the profile to the screen: xrandr --addmode 1200x1000_60.00.
5. Here you replace with the type of connection with which your monitor is connected. Common values ​​are VGA1, DP1 or HDMI1. To find out your connection type, enter "xrandr" in your terminal.