AMD Prepping Fixes & Enhancements For P-State CPUFreq Driver

The AMD P-State CPU frequency scaling driver for Zen 2 and newer processors has been working out well in its roughly two years of being in the mainline Linux kernel. The AMD P-State driver has helped with ensuring modern Ryzen systems are delivering optimal performance and power efficiency. Recently AMD Linux engineers have been working on a few fixes and enhancements to this CPUFreq driver.

Sent out today was the eleventh take on various fixes and enhancements to the AMD P-State Linux driver. Nothing major just some corner-case fixes and minor refinements. Likely most noticeable is the tuned latency and delay values for more accurate timing. The delay and latency values are to be read from the BIOS ACPI tables that are set according to the platform design/requirements rather than relying on previously hardcoded defaults within the AMD P-State driver.

This patch series is also enabling ACPI Collaborative Processor Performance Controls v2 (CPPCv2) for select Zen 2 CPUs too where previously lacking.

The patch series is summed up as:

"It enables CPPC v2 for certain processors in the family 17H, as requested by TR40 processor users who expect improved performance and lower system temperature.

changes latency and delay values to be read from platform firmware firstly for more accurate timing.

A new quirk is introduced for supporting amd-pstate on legacy processors which either lack CPPC capability, or only only have CPPC v2 capability"

The patches continue to be tested and reviewed but will hopefully be mainlined in an upcoming merge window.

Update: Also sent out today are updated AMD P-State Performance Boost patches for those interested.