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My Laptop (Dell Latitude 5480) does not recognize a VGA monitor(Samsung SyncMaster 2243BW) using Ubuntu 16.04LTS. If I plug it in, nothing happens, I can only use the built-in screen (or any HDMI monitor I plug it into).

The said VGA monitor itself works, as I use it with other devices and it connects fine through the cable. My laptop connected without any problems to a VGA monitor earlier this day (sadly I was just testing it out, and have no access to that display).

xrandr while the VGA is plugged in:

~$ xrandr
Screen 0: minimum 8 x 8, current 1920 x 1080, maximum 32767 x 32767
eDP1 connected primary 1920x1080+0+0 (normal left inverted right x axis y axis) 309mm x 173mm
   1920x1080     60.01*+  59.93    48.01  
   1680x1050     59.95    59.88  
   1600x1024     60.17  
   1400x1050     59.98  
   1600x900      60.00  
   1280x1024     60.02  
   1440x900      59.89  
   1280x960      60.00  
   1368x768      60.00  
   1360x768      59.80    59.96  
   1152x864      60.00  
   1280x720      60.00  
   1024x768      60.00  
   1024x576      60.00  
   960x540       60.00  
   800x600       60.32    56.25  
   864x486       60.00  
   640x480       59.94  
   720x405       60.00  
   640x360       60.00  
DP1 disconnected (normal left inverted right x axis y axis)
DP2 disconnected (normal left inverted right x axis y axis)
HDMI1 disconnected (normal left inverted right x axis y axis)
HDMI2 disconnected (normal left inverted right x axis y axis)
HDMI3 disconnected (normal left inverted right x axis y axis)
VIRTUAL1 disconnected (normal left inverted right x axis y axis)

Update: I have tried this VGA not listed in xrandr output: Projector not working, Intel Kabylake Graphics and now sending signal to all of the channels, but the monitor still does not recognizes any signal.

ForestG
  • 61

1 Answers1

2

As this came up quite often, I did a deeper research, and in fact, the mentioned thread contained the answer: I just needed to play a bit around to find a resolution that my monitor supported...

xrandr --addmode HDMI3 800x600
xrandr --output HDMI3 --mode 800x600

So for instance, the 1400x1050 resolution was not supported by the monitor.

The next task was to create a functional thirs desktop, not to mirror the first. The command I used was this:

~$ xrandr --output HDMI3 --mode 1680x1050 --right-of HDMI1 --output HDMI1 --auto --output eDP1 --auto --primary

I wanted to use the VGA monitor as a third one next to my built in (eDP1) and HDMI(HDMI1). It seems that the HDMI3 is in fact the VGA output, which is a converted HDMI after all. This solution works, I can use the 3 screens, but it is not recognized by the display setting tool, and does not have a background etc. but I can move windows to it, which satisfies my needs for now.

ForestG
  • 61