Re: [PATCH v3 00/15] ACPI: CPPC: Fix register access and lifetime bugs

[Rafael J. Wysocki (Intel)]

On Tue, Aug 25, 2026 at 10:25 AM Christian Loehle
<christian.loehle@xxxxxxx> wrote:
>

[cut]

> >>> base-commit: ea2bff00da89d7767d677bb68470130ba96f4928
> >> Gentle ping on this in particular to the CCs not involved in the merge window.
> >> Even just a Tested-by: that the new CPC validation didn't break your platform would
> >> be appreciated!
> >
> > Tested the series on linux-next-20260824.
>
> Thanks for testing, can you dump the CPC descriptors for both revisions?
>
> >
> > With firmware reporting _CPC revision 3, every CPU logs:
> >   ACPI CPPC: CPU0: Performance Limited register cannot use an interlocked SystemMemory access
> >   ACPI CPPC: CPU0: ignoring inaccessible Performance Limited register
>
> Assuming the detection here this is expected.
>
> >
> > cppc_cpufreq still probes and frequency scaling works, though
> > perf_limited interface reads 0 rather than reporting the
> > register as unsupported.
>
> Ack, I'll fix the getter.

This means though that it will miss the 7.3 merge window mark and it
will become 7.4 material.