Re: [PATCH] x86/pm: Save AMD CPUID leaf 7 across S3

[Mario Limonciello <mario.limonciello@amd.com>]

On 8/10/26 14:42, Sean Rhodes wrote:
> On Mon, 10 Aug 2026 at 19:31, Mario Limonciello
> <mario.limonciello@amd.com> wrote:
>>
>>
>>
>> On 8/5/26 20:29, Borislav Petkov wrote:
>>> On Tue, Aug 04, 2026 at 08:22:36PM +0100, Sean Rhodes wrote:
>>>> If you're saying that because there might be a firmware solution, I am
>>>> all ears, but this issue is present with AMI CRB and coreboot+FSP -
>>>> hit a wall trying to fix it there.
>>>
>>
>> Does this only happen in coreboot + FSP?  Or it also happens in latest UEFI?
> 
> Also UEFI

Can you confirm the version you tested?  Is it the latest one?

> 
>>
>> Does it only happen in S3 or also S0i3?
>> How about S4?
> 
> Only S3

OK if it's only S3 it's unlikely that this problem exists on the newer 
systems.  They have switched to only supporting S0i3.

I think you should narrow down your proposed quirk to the single 
affected processor.

> 
>>
>>> I'm making sure you're using the latest one which might potentially have
>>> a fix...
>>>
>>>> Why not?
>>>
>>> Because we're not fixing three things with one patch and without a proper
>>> justification for the other two.
>>>
>>
>> I would expect the restore of this register to be the platform
>> firmware's responsibility.
>>
>> I don't know right now if this a BIOS bug, an suspend/resume bug, or how
>> wide of an impact it is.
>>
>> Your fix might make sense for "this single platform", but we don't have
>> any evidence it's needed for any other one just yet.
>>
>> We shouldn't make changes because there "might" be a problem.  We need
>> affirmation from testing or an assertion from the BIOS team.
> 
> Ack