Re: [PATCH v3 06/12] x86/amd_nb: Use topology info to get AMD node count

[Mario Limonciello]

On 10/23/25 12:06 PM, Michal Pecio wrote:
> On Thu, 23 Oct 2025 11:22:29 -0500, Mario Limonciello wrote:
> > As this is an ancient BIOS this reminds me of some related commits:
> >
> > aa06e20f1be6 ("x86/ACPI: Don't add CPUs that are not online capable")
> > a74fabfbd1b70 ("x86/ACPI/boot: Use FADT version to check support for
> > online capable")
> >
> > Does reverting that second one help?
>
> Not sure if it's worth trying? My BIOS predates the ACPI 6.3 spec by
> several years and (if I understand correctly) MADT revision is 1.
>
> It seems Yazen guessed right: they list 6 APICs and mark absent ones
> as not enabled. But I don't think we can assume any ACPI 6.3 flags to
> be valid here.
>
> I wonder if some quick check could recognize those consumer CPUs and
> simply ignore hotplug there? AFAIK it was never a thing on AM3.
>
> Michal

Oh if the MADT revision is that old, then yeah reverting won't do 
anything here.