Ok just to close the loop here. Problem persisted with Intel Arc (the only thing I forgot to do was disable REBAR, but I don't think this is a related issue).

Upon installing Radeon RX 6400, pass through worked without any issue. Of note, on the Arc I got two separately numbered PCI devices 0000:0b and 0000:0a where as with the AMD it was 0000.08.01 and .02. I'm not sure if that helps hint at the issue --something to do with grouping and not grouping? This is way above my head but I noticed the difference.

I'm still having issues with pass through into Linux but that is a separate topic. Looks like we have a good discussion of this issue on the other post and so I will stay on that one going forward.

Thank you!

@olivierlambert ok perhaps I didn't include the full address. I've got the card replaced and now managed to corrupt grub (it's a Sunday...) so once I fix that we'll see what this new card has to offer in comparison. As a note I will say the AMD card did immediately pick up the console so I can already see there seems to be a better level of compatibility.

More to come later...!

@TeddyAstie great will take a look this weekend. Is there anything in particular you want us to test / check out?

@andSmv

From LSPCI:

0a:00.0 Audio device: Intel Corporation DG2 Audio Controller
0b:00.0 VGA compatible controller: Intel Corporation DG2 [Arc A310] (rev 05)

With xl pci-assignable-list :

0000:01:00.6
0000:01:00.4
0000:0b:00.0
0000:01:00.0
0000:01:00.3

Here you go...hope this helps!

@olivierlambert I'm going to swap in an AMD card today and will let you know if anything changes!