Re: [PATCH] cpufreq: intel_pstate: Use HYBRID_SCALING_FACTOR_ADL for Bartlett Lake

[Henry Tseng <henrytseng@qnap.com>]

On Wed, 13 May 2026 12:40:36 +0200, "Rafael J. Wysocki" <rafael@kernel.org> wrote:
> On Wed, May 13, 2026 at 12:29 PM Henry Tseng <henrytseng@qnap.com> wrote:
> >
> > Bartlett Lake P-core only SKUs (e.g. Intel Core 9 273PE)
> > do not report X86_FEATURE_HYBRID_CPU and are not in
> > intel_hybrid_scaling_factor[].  In hwp_get_cpu_scaling(), the
> > non-hybrid fallback then applies core_get_scaling() (100000),
> > producing cpuinfo_max_freq values that exceed the documented Max
> > Turbo Frequency:
> >
> >   intel_pstate: CPU0: PERF_CTL turbo = 57
> >   intel_pstate: CPU0: HWP_CAP guaranteed = 30
> >   intel_pstate: CPU0: HWP_CAP highest = 70
> >   intel_pstate: CPU0: HWP-to-frequency scaling factor: 100000
> >   intel_pstate: set_policy cpuinfo.max 7000000 policy->max 7000000
> >   ...
> >   intel_pstate: CPU12: PERF_CTL turbo = 57
> >   intel_pstate: CPU12: HWP_CAP guaranteed = 30
> >   intel_pstate: CPU12: HWP_CAP highest = 73
> >   intel_pstate: CPU12: HWP-to-frequency scaling factor: 100000
> >   intel_pstate: set_policy cpuinfo.max 7300000 policy->max 7300000
> >   ...
> >
> > Per the Intel datasheet [1], the Intel Core 9 273PE specifies:
> >
> >   Performance-cores:                                 12
> >   Efficient-cores:                                   0
> >   Max Turbo Frequency:                               5.7 GHz
> >   Intel Thermal Velocity Boost Frequency:            5.7 GHz
> >   Intel Turbo Boost Max Technology 3.0 Frequency:    5.6 GHz
> >   Performance-core Max Turbo Frequency:              5.4 GHz
> >   Performance-core Base Frequency:                   2.3 GHz
> >
> > Bartlett Lake P-cores are Raptor Cove cores, per
> > commit d466304c4322 ("x86/cpu: Add CPU model number for Bartlett
> > Lake CPUs with Raptor Cove cores").  The Alder Lake and Raptor Lake
> > P-core entries in intel_hybrid_scaling_factor[] use
> > HYBRID_SCALING_FACTOR_ADL (78741).  The same factor applies to
> > Bartlett Lake.
> >
> > Add Bartlett Lake to intel_hybrid_scaling_factor[] with
> > HYBRID_SCALING_FACTOR_ADL so HWP performance levels map to the
> > correct CPU frequencies matching the datasheet's Max Turbo Frequency.
> >
> > [1] https://www.intel.com/content/www/us/en/products/sku/245717/intel-core-9-processor-273pe-36m-cache-up-to-5-70-ghz/specifications.html
> >
> > Signed-off-by: Henry Tseng <henrytseng@qnap.com>
> > ---
> >  drivers/cpufreq/intel_pstate.c | 1 +
> >  1 file changed, 1 insertion(+)
> >
> > diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c
> > index 1292da53e5fc..2737e51cff34 100644
> > --- a/drivers/cpufreq/intel_pstate.c
> > +++ b/drivers/cpufreq/intel_pstate.c
> > @@ -3734,6 +3734,7 @@ static const struct x86_cpu_id intel_hybrid_scaling_factor[] = {
> >         X86_MATCH_VFM(INTEL_RAPTORLAKE, HYBRID_SCALING_FACTOR_ADL),
> >         X86_MATCH_VFM(INTEL_RAPTORLAKE_P, HYBRID_SCALING_FACTOR_ADL),
> >         X86_MATCH_VFM(INTEL_RAPTORLAKE_S, HYBRID_SCALING_FACTOR_ADL),
> > +       X86_MATCH_VFM(INTEL_BARTLETTLAKE, HYBRID_SCALING_FACTOR_ADL),
> >         X86_MATCH_VFM(INTEL_METEORLAKE_L, HYBRID_SCALING_FACTOR_MTL),
> >         X86_MATCH_VFM(INTEL_LUNARLAKE_M, HYBRID_SCALING_FACTOR_LNL),
> >         {}
> > --
> 
> Do I understand correctly that
> 
> https://lore.kernel.org/linux-pm/4523296.ejJDZkT8p0@rafael.j.wysocki/
> 
> works for you?
> 

With these patches applied, it works on Intel Core 9 273PE (Bartlett
Lake).  hybrid_get_cpu_type() returns 0 and cpuinfo_max_freq matches
the datasheet.

Thanks,
Henry