Re: [PATCH 2/4] x86/amd_nb: add support for newer PCI topologies

Srinivas Pandruvada
2018-11-07T23:30:52Z

[...]

> Sure, you can't *force* OEMs to supply a given ACPI device, but you
> can certainly say "if you want this functionality, supply INT3401
> devices." That's what you do with PNP0A03 (PCI host bridges), for
> example. If an OEM doesn't supply PNP0A03 devices, the system can
> boot just fine as long as you don't need PCI.
>
> This model of using the PCI IDs forces OS vendors to release updates
> for every new platform. I guess you must have considered that and
> decided whatever benefit you're getting was worth the cost.

Not worth cost. This is a pain. Every release we end up adding a single
line change to many drivers adding a PCI device id.
Since there is no unique class_mask for PCI device for these devices,
we need to add device_id for each generation even if there is no
change.
Instead if we have some feature to say don't enumerate for PCI device
id < X and a black list, it will save lot of work.

Thanks,
Srinivas