Could you send me your devicetree.cb or Config.lb?
My thought is that you can put chip drivers/generic/generic around the video card so that it doesn't get the 780 ops.
Does it get any 780 ops at all? I'd think it only does when a struct pci_driver is catching it?
I haven't seen the device tree, but the 780 code is initializing it. That seems to be the only difference between the failing and functioning logs.
Thanks, Myles