I have dual monitor setup: 27-inch Dell via DisplayPort and 24-inch Iiyama via HDMI. From time to time the Dell monitor via the display port after boot is showing:

"No signal"

and then goes into sleep mode. If I open displays from:

  • Start menu
  • Preferences
  • Displays

Linux Mint/Ubuntu no signal HDMI/DP

  • identify the problem:
    • xrandr
    • monitors.xml - nano ~/.config/monitors.xml
    • xorg.conf - nano /etc/X11/xorg.conf
  • fix the problem
    • rm ~/.config/monitors.xml

If you have more problems with Linux Mint and displays you can check this article:

How to identify the monitor problems

I can see that monitor is recognized and working - but the monitor is not working. Mouse is moving on the not working monitor and also application are "displayed" there. The problem was persistent after reboot.

python_online_editor_2020

If I change some settings like change the primary monitor the problem is solved. I can see picture on both monitors.

The monitor is visible from - xrandr:

xrandr

Screen 0: minimum 8 x 8, current 4480 x 1440, maximum 32767 x 32767
DVI-D-0 disconnected (normal left inverted right x axis y axis)
HDMI-0 connected primary 1920x1080+2560+0 (normal left inverted right x axis y axis) 527mm x 296mm
   1920x1080     60.00*+  59.94    50.00    60.00    50.04  
   1680x1050     59.95  
   1600x1200     60.00  
   1440x900      59.89  
   1280x1024     75.02    60.02  
   1280x960      60.00  
   1280x720      59.94    50.00  
   1152x720      60.00  
   1024x768      75.03    60.00  
   800x600       75.00    60.32  
   720x576       50.00  
   720x480       59.94  
   640x480       75.00    59.94    59.93  
DP-0 disconnected (normal left inverted right x axis y axis)
DP-1 disconnected (normal left inverted right x axis y axis)
DP-2 connected 2560x1440+0+0 (normal left inverted right x axis y axis) 597mm x 336mm
   2560x1440     59.95*+
   2048x1080     60.00    24.00  
   1920x1080     60.00    59.94    50.00  
   1600x1200     60.00  
   1280x1024     75.02    60.02  
   1280x720      60.00    59.94    50.00  
   1152x864      75.00  
   1024x768      75.03    60.00  
   800x600       75.00    60.32  
   720x576       50.00  
   720x480       59.94  
   640x480       75.00    59.94    59.93  
DP-3 disconnected (normal left inverted right x axis y axis)

Nothing suspicious in: xorg.conf:

nano /etc/X11/xorg.conf

If you have similar problems you can check your monitor configuration by:

nano ~/.config/monitors.xml

How to fix the no signal issue

The first time I saw this problem was when I change my monitor - I got the new 27-inch Dell which replaced old Benq connected with DVI. I run the command above and found out that old monitor was present in the configuration but the new one was missing.

In order to solve the problem I've just deleted the file:

rm ~/.config/monitors.xml

This solve the problem and next boot up monitor was working as expected.

Bonus 1: Move mouse courser to problematic monitor

It may sounds weird but best solution seems to be moving the mouse cursor on the monitor which get no signal. Let say you have two monitors:

  • M1 - HDMI - working fine
  • M2 - DP - no signal after login

Then you need to place the mouse courser on the M2 before loging. Sometimes the mouse will be moved back to M1 but you can move it again to M2 - which seems to be best option in order to keep DP with signal.

Bonus 2: Problem could be related to encryption

If the Linux Mint installation is encrypted this might slow down loading of the settings which can lead to:

  • The monitor report no signal
  • Linux Mint show that signal is sent

In this case I've notice that best is to wait few seconds after the unlock of the encrypted volume and before entering the Linux Mint password. This ensures that setup and drivers are loaded and working fine.

Note: I've notice similar behavior for program RedShift - the program needs some time before to start working normally - something like 1 minute delay.