(In reply to Lukas Wunner from comment #66)
> Hm, the multifunction bit is set. Try adding an msleep(100) after setting
> the bit at offset 0x488 and before re-reading the header type register. 100
> ms is likely way too much, this is just to ensure it's not too short.
No success. 
> Also, try changing DECLARE_PCI_FIXUP_CLASS_HEADER to
> DECLARE_PCI_FIXUP_CLASS_EARLY. Shouldn't make a difference but maybe I
> missed something.
No success.
> Does it work if you just set gpu->multifunction = 1?
Nope.
Completely absurd. Looks a bit like the mentioned bug in 4.9 though it vanishes
after pci init.