Last year with the ACPI 6.6 specification release came revised Collaborative Processor Performance Control (CPPC) support for enhancing the capabilities around this standard for OS management of the performance of CPU cores using an abstract performance scale. That CPPC v4 support is now being worked on for the acpi_cppc Linux driver by NVIDIA engineers.

Multiple processor vendors continue leveraging ACPI CPPC for performance management. For those CPU vendors using the generic CPPC Linux driver, CPPC v4 support is being wired up by NVIDIA. NVIDIA engineer Sumit Gupta explained of the CPPC v4 changes in the ACPI 6.6 specification:

"Add initial kernel support for CPPC v4 (ACPI 6.6, Section 8.4.6), which extends the _CPC package from 23 to 25 entries with two optional fields:

- OSPM Nominal Performance (8.4.6.1.2.6): write-only register used by OSPM to tell the platform what it considers nominal. The platform classifies performance above this as boost and below as throttle for power/thermal decisions.

- Resource Priority (8.4.6.1.2.7): Package of Resource Priority Register Descriptor sub-packages. Full parsing is not yet implemented; such entries are marked as unsupported."

[1]The patch series is out for review on the Linux kernel mailing list. Presumably NVIDIA's upcoming Vera CPUs will be supporting CPPC v4 capabilities given the timing of these patches.



[1] https://lore.kernel.org/linux-acpi/20260427051823.280419-1-sumitg@nvidia.com/