Comment # 15 on bug 798308 from Koenraad Lelong

Created attachment 657910 [details]
xrandr with DP- and VGA cables attached

This is the xrandr-output when cables from the same laptop are connected to the
DP- and VGA-port of the SAME monitor.

When I connect only the VGA-cable and boot,I have a image via the VGA-port, the
LED of the monitor is blue.

When I connect only the DP-cable and boot, I don't have an image on the
monitor. There is no backlight, the LED is orange.
When I force the monitor to scan it's ports, the LED turns blue, the backlight
goes on (because there is text on the monitor, saying it's scanning the
inputs). Since the monitor does not find input, the LED goes orange after a
while (after 5 to 10 seconds scanning). xrandr does find the monitor though.

Disconnecting and connecting the DP-cable triggers something so xrandr shows
different output, according to the connected state of the cable.

I hope all is still clear.
Unfortunately, I don't have anything that has a DP so I could try the monitor
with that.