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Is it possible to have 2 extended monitors and get the third being a mirror of one of the two extended?

I'm pretty sure it's not possible through the interface but it may be possible through commands or configuration file.

If it's seems weird for you, here is my setup :

  • 2 monitors, pretty classic working with dual monitor
  • 1 big TV that I use as a projector to show things off to people (on meetings for example)

2 Answers 2

20

You need to look at xrandr command

May be something like:

xrandr --output SCREEN1 --output SCREEN2 --output SCREEN3 --same-as SCREEN2

where SCREEN3 mirrors SCREEN2.

Replace SCREEN1, SCREEN2, SCREEN3 with the appropriate name that you get with the xrandr command (without any option).

For example, LDVS1, HDMI1, VGA1, etc ...

5
  • 3
    Well well using xrandr was the first thing I tried and it didn't work, but thanks to you I tried it again and it worked. It wasn't straightforward I had to do some manipulation to get it working but at the end it worked. I'll see if I find out what exact manipulation was blocking it or which one deblocked it. Thks!
    – Ghetolay
    Apr 30, 2015 at 21:57
  • 4
    A good way to get a feel for xrandr is to install arandr, which is a GUI that will generate xrandr scripts to match your current configuration. From there you can tweak the script to achieve your desired state. Jan 13, 2018 at 19:31
  • Hi @Ghetolay could you please share how to use xrandr for 3 monitors, but only two are mirror of each other? Thanks!
    – swdev
    Jun 11, 2018 at 15:37
  • Exactly as stipulated on this anwser. In this example SCREEN2 and SCREEN3 will be mirrors.
    – Ghetolay
    Jun 12, 2018 at 8:50
  • And how can I make these settings permanent? Sep 22, 2019 at 3:08
5

If you have an NVIDIA graphics card, you can do this rather easily in NVIDIA X Server Settings.

Under X Server Display Configuration, select a monitor and for its position, select "Same as" and then the name of your monitor, for example "ViewSonic VX2552 Series".

Example of mirrored displays

Fortunately for me, my monitor and TV are the same resolution!

1
  • I'm on ATI but this will be useful for those owning a NVIDIA thks.
    – Ghetolay
    Jul 18, 2016 at 8:08

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