I checked just now, and ARC says my CPU (i5-3470) supports VT-d and my motherboard has it has an option.
I enabled it in the bios but I am not sure I have done it correctly as
Virtualisation: VT-x? I don’t know if that is relevant though.
I would love to get GPU pass-through working - or at least use it as a way to test the GPU further - so any pointers on that would be greatly appreciated.
Interestingly enough i still had a monitor connected to the DVI connection from testing all ports yesterday when i rebooted to change the BIOS… If i have a monitor connected to the GPU when i reboot it uses that as the output and it works initially but the OS never loads. It always stops just after starting gnome (photo below). this gives me both hope and concern, hope that it may work somehow, but concern that the issue is more serious and even if i try and use it in some headless form it will not work.
FWIW I also booted windows. similarly it boots but plugging in a monitor does nothing. in device manager i get a warning triangle and the message:
This device cannot find enough free resources that it can use. (Code 12)
If you want to use this device, you will need to disable one of the other devices on this system.
the resources tab shows the same message and no options.
just so its all in one place here is a summary of the permutations i have tested:
onboard graphics as primary, no monitor connected to GPU:
boots and runs fine ubuntu see GPU but i dont know if its working. plugging in a monitor appears to do nothing (montior wakes for second then goes to sleep with no signal message)
onboard graphics as primary, monitor connected to onboard and gpu (DVI,HDMI&DP):
outbputs to GPU as main monitor always. ubuntu loading screen comes up, then switches to progress output and hangs around when gnome is launched
gpu as main output, monitor connected to GPU at boot (onboard connection can be plugged in or not):
freezes at bios splashscreen and after a while gives a single beep
gpu as main output and no montor connected to GPU (again onboard having a monitor plugged in seems irrelevant):
5 beeps from bios.