Ubuntu – How to enable monitor from terminal

command linedisplaymultiple-monitors

I accidentally disabled my monitors, so when I log in I land on a blank, back-lit screen. I can open terminals with Ctrl+Alt+F#, so how do I enable the monitor from terminal?

I tried xrandr, but it can't open display. xset does not work either. I found this question which closely resembles my problem. The answer provides a script to be put in /etc/X11/Xreset.d.

Running it does not solve my problem (though it is likely I don't understand how to use it properly). I think I somehow made the new default to be "disable monitors".

Running Ubuntu Studio 13.10. I do not have nVidia drivers. I can't find an xorg.conf file to remove. Thankful for any and all input!

Edit: Output of command xrandr -d :0

Screen 0: minimum 320x200, current 1366 x 768, maximum 32767 x 32767
LVDS1 connected 1366x768+-32768+-32768 (normal left inverted right x axis y axis) 344mm x 192mm
    1366x768    60.0*
    1360x768    59.8    60.0
    1024x768    60.0
    800x600     60.3    56.2
    640x480     59.9
VGA1 disconnected (normal left inverted right x axis y axis)
HDMI1 disconnected (normal left inverted right x axis y axis)
DP1 disconnected (normal left inverted right x axis y axis)
VIRTUAL1 disconnected (normal left inverted right x axis y axis)

Still being a CLI beginner I fail to understand from man xrandr how to switch on (there is an off option) or enable displays. Output of xrandr --auto is Can't open display

Edit 2: Output of xrandr -d :0 --auto

Configure crtc 0 failed

Maybe I just have to reinstall X11?

Edit 3: Outputs of suggested commands / which xset commands I tried:

xrandr -d :0 output LVDS1 --auto

    configure crtc 0 failed

xset q and xset dpms force on both return

    unable to open display ''''

No difference for sudo commands.

Edit 4: More futile attempts and the potential discovery of a security issue

  • 4.1 I've tried to reinstall Xorg and X11, then I ran sudo apt-get install --reinstall xserver* which failed with this output:

    (many versions of this:)
    Note, selecting 'xserver-xorg-something' for regex 'xserver*'
    Some packages could not be installed. This may mean that you have
    requested an impossible situation or if you are using the unstable
    distribution that some required packages have not yet been created
    or been moved out of Incoming.

    The following information may help to resolve the situation:
    The following packages have unmet dependencies:
    xserver-xorg-input-mtrack : Conflicts: xserver-xorg-input-multitouch
    but 1.0~rc2+git20110312-2build4 is to be installed
    E: Unable to correct problems, you have held broken packages.
  • 4.2 Next I logged in as guest and logged in as myself through tty Ctrl+Alt+F# and ran the same xrand commands as above (OP and edits 1-3), with the same output as far as I can see.

  • 4.3 Then I created a new_user with full admin rights and repeated 4.2 via tty.

  • 4.4 SECURITY ISSUE? No, just a need of awareness. Not related to this subject, details at launchpad

It begins looking like a system reinstall is necessary 🙁

Best Answer

After running this command switch immediately to the tty where the screen is black, and after 5 seconds the screen should show up.

sleep 5 && xrandr -d :0 --output LVDS --auto

The xrandr command will turn on your main screen. It only seems to work if you're currently on the tty where your display manager is run, hence the sleep to give you some time to be able to switch.