Ubuntu – Can’t physically turn-off built in display

20.04displaylaptopnvidia

TLDR; Is it possible to physically turn off a built in display for a laptop so a docking station could utilise all available display outs.

I am struggling to physically turn-off a laptops built in display for Ubuntu 20.04. Due to the built in display always being available, when I attempt to connect more than a total of 3 [internal or external] monitors to my Dell Docking Station WD19 Thunderbolt in Settings > Screen Display I receive the error (in the windows title bar):

Changes Cannot be Applied
This could be due to hardware limitations

It is worth noting that the documentation for the docking station states:

NOTE: : Linux operating system is unable to physically turn-off built-in display, the external display numbers will be one less than the display numbers listed in above tables.

Additional Info:

  • Graphics card: NVIDIA GeForce GTX 1650 4GB GDDR5
  • Graphics driver: NVIDIA Corporation: TU117M [GeForce GTX 1650 Mobile / Max-Q] - Using NVIDIA driver metapackage from nvidia-driver-440

Best Answer

You can by using the preferences command for X server (http://systembash.com/content/how-to-turn-off-your-monitor-via-command-line-in-ubuntu/)

  • To turn off the monitor $ xset dpms force off

  • To turn on the monitor $ xset dpms force on Well if you press any key, the monitor will wake up, so to turn the screen off without turning it on use the below command:

    sleep 3; xset dpms force off

To determine the display you can use the command

'$ xrandr'

You can even run xrandr --output <DISPLAY_NAME> --brightness 0 to manually turn off display for a selected monitor.

NOTE: Once You $ sleep 3; xset dpms force off, you won't be able to turn on the display by clicking or pressing any key, then you've to blindly enter the code or use secondary display.

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