[BUG] intel_pstate: CPU frequencies miscalculated/incorrectly detected on Arrow Lake hardware

[Aaron Rainbolt]

On Wed, 26 Nov 2025 17:00:31 -0600
Aaron Rainbolt <arainbolt at kfocus.org> wrote:

> (Sorry for this rather malformed email, Claws *still* can't find the
> thread for some reason so I'm having to resort to a "mailto" link off
> of lore.kernel.org.)
> 
> > I asked for some dumps before. We can try to inform the OEM of the
> > system as this is a BIOS tables issue. What is the make and model of
> > your system?
> >
> > Thanks,
> > Srinivas  
> 
> We're actively working on getting the dumps you mentioned previously
> for all three affected machines, along with the model info and some
> benchmarking results with our current production kernel and the latest
> mainline kernel. It's taking a bit longer than we expected, but we're
> pretty close. I should have more info by Monday if all goes according
> to plan on our end.

Hi Srinivas,

We ended up finding out that the frequency misreporting issue impacted
more machines than we thought, in different ways than we thought, so we
ended up a bit delayed. We did get many of the dumps you requested, and
also did some tests to see exactly how frequencies were getting
mis-reported. The actual dumps and the results of testing are long, so
I've attached them instead of pasting them in.

Some key things to note are:

* The manufacturer and model codes for each machine we tested are in the
  "2025-11-26_cpu_freq_report.md" file.
* We're seeing the misreporting problems on at least five models of
  machines from three different manufacturers (ASUS, Clevo, and
  TongFang). Every Arrow Lake system we've checked is affected. This
  doesn't rule out BIOS issues I guess, but it seems somewhat unlikely
  that three manufacturers would mess up their BIOS in the same way.
  The reports are for three models of Clevo machines and one ASUS NUC,
  we haven't gotten final test results for the TongFang machine in
  question.
* On all affected systems we've seen, *either* P-core frequency is
  mis-reported, *or* E-core frequency is mis-reported, but never both.
  One core type always has its frequencies reported correctly, the
  other core type's frequencies are reported incorrectly.
* All systems tested were using the latest BIOS from the manufacturer,
  to our awareness.

Thanks again, and let me know if there's any other info we can provide.

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