ron minnich has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/36221 )
Change subject: WIP: Add configurable ramstage support for minimal PCI scanning ......................................................................
Patch Set 14:
Patch Set 14:
So have we gone from wanting to not assign resources for certain devices to not assigning resources for almost all devices unless someone explicitly changes the code?
- I don't think that was our original problem. At least for USB4/thunderbolt there's a finite set of viddids we can purposefully not allocate resources for.
I.e. a blacklist? That actually looks more complex to me than this current fairly simple solution.
What if I express what you just said a little differently?
We are saying that for certain select mainboards, where such a capability is of interest, we can enable letting the payload do almost all the work of PCI configuration.
In that case, for those mainboards, yes, we can skip just about all devices, and this is something several companies would like to have. They've expressed interest at OSFC, on the coreboot telecon, on the mailing list, to me personally, and in this CL discussion.
We're not claiming this approach works for everything. Then again, we know the current system is not working for everything either, and as Jeremy points out, there are problems coming our way; a general solution that works for all payloads seems increasingly unlikely; and, even if likely, starts to look pretty complicated.
The jury is still out on this current approach; people are supposed to be reporting back to me with some results on real hardware but I have not heard anything yet.