Re: [PATCH v2 1/2] ACPI: CPPC: Add support for CPPC v4

Pierre Gondois
2026-04-30T16:26:31Z

Hello Sumit,

On 4/30/26 16:24, Sumit Gupta wrote:
> CPPC v4 (ACPI 6.6, Section 8.4.6) adds two optional entries to the
> _CPC package:
>
> 1. OSPM Nominal Performance (8.4.6.1.2.6): A write-only register that
> lets OSPM inform the platform what it considers nominal performance.
> The platform classifies performance above this level as boost and
> below as throttle for its power/thermal decisions.
>
> 2. Resource Priority (8.4.6.1.2.7): A Package of Resource Priority
> Register Descriptor sub-packages that allow OSPM to set relative
> priority among processors for shared resources (boost, throttle,
> L2/L3 cache, memory bandwidth). Parsing the full structure is not
> yet supported; such entries are marked as unsupported.
>
> Add v4 _CPC table parsing (25 entries) and update REG_OPTIONAL to
> mark the two new registers as optional.
>
> Signed-off-by: Sumit Gupta <sumitg@nvidia.com>
> Reviewed-by: Mario Limonciello (AMD) <superm1@kernel.org>

Reviewed-by: Pierre Gondois <pierre.gondois@arm.com>