Ubuntu Detects 2 monitors when I only have one

This seems to be an issue with certain motherboards that have an HDMI and a Display Port. I figured out that either my Gateway ZX6800 Touch-Screen is using a certain Laptop motherboard with the on-board Intel HD chipset that supports this or it is seeing the IR Blaster or TV Tuner and driving it as a monitor.

Either way the fix is: Edit /etc/default/grub add "video=VGA-1:d" between the quotes in the GRUB_CMDLINE_LINUX line update-grub

Look in /sys/class/drm for a list of your computers outputs.Mine was labelled as "card0-VGA-1". Just remove the "card0-" and that's the name of the output in question.

I had similar issue with an integrated Intel HD graphics unit (JUSTOP G-PC iA8 Desktop) and missing mouse pointer.

I thought I would add additional help..

to get the correct video to disable...

ls /sys/class/drm

note the name that is similar to the output from

xrandr -q

e.g. my connected (but non existent extra screen was DSI1 in xrandr but card0-DSI-1 in /sys/class/drm)

based on this information the correct kernal data from /sys/class/drm I was then able to correct the syntax in my...

/etc/default/grub

file to read

GRUB_CMDLINE_LINUX="video=DSI-1:d"

then ran

sudo update-grub

and rebooted, now only one HDMI screen connected and working mouse. Hope this helps other people.