I have a Dell XPS 13 with Ubuntu 16.04. First time I've connected an external monitor (1080p TV) it works just fine. But some day Ubuntu stop detecting it.
If I boot the system from USB with a fresh Ubuntu 16.04 the monitor is detected correctly. It seems that some information in the system is preventing this monitor to be detected.
How can I reset the external display configuration to solve this? My system has Intel display controller.
This is the output of xrandr with the monitor connected (but not detected):
$ 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) 294mm x 165mm
1920x1080 59.93*+ 59.93
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)
VIRTUAL1 disconnected (normal left inverted right x axis y axis)
When working, DP1 is the one used by the system.
Thanks a lot, D.
