Comment 5 for bug 2066126

I had a ghost monitor indeed. Per's workaround from bug 2060268 worked to eliminate the ghost monitor:

"""
Another Workaround:
I believe this is the simpledrm driver not asking for the conflicting framebuffers to be unregistered.
You can try to add "initcall_blacklist=simpledrm_platform_driver_init" to your kernel command line parameters to make sure the simpledrm driver is not loading on boot.

Add to your kernel command line like this. Open your terminal:
sudo nano /etc/default/grub
add "initcall_blacklist=simpledrm_platform_driver_init" to where it says GRUB_CMDLINE_LINUX_DEFAULT=”quiet splash", so it looks like this:
GRUB_CMDLINE_LINUX_DEFAULT=”quiet splash initcall_blacklist=simpledrm_platform_driver_init”
ctrl+O for save and ctrl+X for quit. Back in the terminal write:
sudo update-grub
reboot

This fixed the issue for me.
"""

Let's see if the screen works properly now