On some systems, the boost ratio cannot be accurately calculated
using linear interpolation of CPPC performance values because the
performance-to-frequency mapping is not linear across all cores.

This series introduces support for the CPPC HighestFreq register.  This
register is under a proposal with ASWG at the moment and trending for
inclusion in ACPI 6.7.

This optionally provides the actual highest frequency eliminating
the need for interpolation. When available, this frequency value is used
for more accurate CPU capacity calculations and boost ratio determination.

This series brings the existing CPPC definitions up to ACPI 6.6 and then
adds support for the ACPI 6.7 proposal.

---
v2:
 * Drop CPPC v4 patches, these are submitted separately by Sumit Gupta [1]

Link: https://lore.kernel.org/linux-pm/20260430142430.755437-1-sumitg@nvidia.com/ [1]

Mario Limonciello (5):
  Revert "ACPI: CPPC: Adjust debug messages in amd_set_max_freq_ratio()
    to warn"
  ACPI: CPPC: Add support for reading HighestFreq
  ACPI: CPPC: Refactor boost ratio handling
  cpufreq/acpi-cpufreq: Use amd_get_boost_ratio()
  cpufreq/amd-pstate: Get highest freq from CPPC if available

 arch/x86/kernel/acpi/cppc.c    | 122 ++++++++++++++++++---------------
 drivers/acpi/cppc_acpi.c       |  31 ++++++---
 drivers/cpufreq/acpi-cpufreq.c |  17 +++--
 drivers/cpufreq/amd-pstate.c   |  18 +++--
 include/acpi/cppc_acpi.h       |  16 ++++-
 5 files changed, 123 insertions(+), 81 deletions(-)

-- 
2.43.0

Hello Mario,

On 5/5/2026 4:31 AM, Mario Limonciello wrote:
> On some systems, the boost ratio cannot be accurately calculated
> using linear interpolation of CPPC performance values because the
> performance-to-frequency mapping is not linear across all cores.
> 
> This series introduces support for the CPPC HighestFreq register.  This
> register is under a proposal with ASWG at the moment and trending for
> inclusion in ACPI 6.7.
> 
> This optionally provides the actual highest frequency eliminating
> the need for interpolation. When available, this frequency value is used
> for more accurate CPU capacity calculations and boost ratio determination.
> 
> This series brings the existing CPPC definitions up to ACPI 6.6 and then
> adds support for the ACPI 6.7 proposal.
> 
> ---
> v2:
>  * Drop CPPC v4 patches, these are submitted separately by Sumit Gupta [1]
> 
> Link: https://lore.kernel.org/linux-pm/20260430142430.755437-1-sumitg@nvidia.com/ [1]

I tested the series on top of v7.1-rc2 + Sumit's patch with both
amd-pstate and acpi-cpufreq on my 3rd Generation EPYC and everything
seems to be in order. Feel free to include:

Reviewed-by: K Prateek Nayak <kprateek.nayak@amd.com>
Tested-by: K Prateek Nayak <kprateek.nayak@amd.com>

-- 
Thanks and Regards,
Prateek