Setup: Laptop with two external monitors. One monitor connected by the HDMI port on the laptop. The other monitor connected by usb using a Sabrent usb to HDMI adapter. OS: Ubuntu 16.04.
After doing a Ubuntu dist-upgrade and rebooting my video cards started acting goofy. When my Sabrent usb to hdmi card is plugged into my laptop only it gets the picture assigned to it. If I unplug it and reboot the laptop screen and HDMI monitor both get the picture. I was suspicious that Nvidia drivers has been installed. This was the case. Here was my fix:
- sudo apt-get purge nvidia-*
- sudo apt-get remove –purge xserver-xorg
- sudo apt-get install xserver-xorg
- sudo dpkg-reconfigure xserver-xorg
I shut down my system, plugged in the HDMI and the USB monitors and rebooted. All three monitors worked.