Nico Huber has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/31448 )
Change subject: src/device/pci: Add support for discrete VGA initialization and OpROM loading ......................................................................
Patch Set 1: Code-Review-1
Mike, so turns out I did already look into this (CB:20638) and asked you to test the effect of MULTIPLE_VGA_ADAPTERS. Can you please do that?
Also, IIRC, I asked to check what Linux actually requires to bring graphics up. So we don't have to twist coreboot for some legacy stuff that isn't really required. If the rumors are true, Linux only needs a way to find the Atom- BIOS code and doesn't require the firmware to execute any of it. So please, find out what ways Linux' driver sup- ports to acquire the AtomBIOS. There might be much clea- ner ways than running this nasty stuff in coreboot.
AFAIK it is forbidden to route the IO and MMIO regions related to VGA Option Rom to two different PCI functions.
Yeah that just wouldn't work.
Not sure how you could even run two option roms without redoing the routing in between.
I'm not sure about this. But a hunch tells me that the option rom shouldn't assume the routing but check it and act accordingly.