With Ubuntu 14.04 and my new System76 laptop. I shut down after being connected to a monitor at home. Came into work and connected to a monitor.
The monitor was not detected in
All Settings -> Displayed
I tried several other monitors and HDMI cables. All had the same problem. I tried rebooting the laptop and rebooting the monitor, all to no avail. When I looked at
xrandr to dive a level deeper, it did not list an HDMI adapter
doug@76:~$ xrandr Screen 0: minimum 320 x 200, current 1920 x 1080, maximum 32767 x 32767 eDP1 connected (normal left inverted right x axis y axis) 1920x1080 60.1 + 59.9 1680x1050 60.0 59.9 1600x1024 60.2 1400x1050 60.0 1280x1024 60.0 1440x900 59.9 1280x960 60.0 1360x768 59.8 60.0 1152x864 60.0 1024x768 60.0 800x600 60.3 56.2 640x480 59.9 VGA1 disconnected (normal left inverted right x axis y axis) VIRTUAL1 disconnected (normal left inverted right x axis y axis)
Finally I got fed up and explicitly shut down. Once I did this, the HDMI began to be detected.
I was trying to figure out if there was a simple human error involved or how I might go about troubleshooting this problem further?