On Fri, Apr 1, 2016 at 3:33 AM, Patrick O'Callaghan <pocallaghan@gmail.com> wrote:
when I suspend the system and try to
restart it, nothing will happen until I physically remove the dongle
from the extension cable. The screen will then come back to life

At what point is the boot process when the screen comes back to life? Has the system actually booted or does the grub2 screen come up when you remove the dongle? If the latter, the system is probably trying to boot from USB. I have had that problem when having certain USB devices plugged in. If you don't ever need to boot from a USB device, you might be able to disable that in BIOS/UEFI.

--Greg