Closed pyamsoft closed 6 years ago
Taken from the intel_pstate kernel documentation:
For contemporary Intel processors, the frequency is controlled by the processor itself and the P-states exposed to software are related to performance levels. The idea that frequency can be set to a single frequency is fiction for Intel Core processors. Even if the scaling driver selects a single P state the actual frequency the processor will run at is selected by the processor itself.
The pstate driver also seems to ignore the values set in the cpufreq and intel_pstate sys directories after a resume from system suspend.
The pstate-driver does not respect the settings for minimum, and maximum performance percentages. As a result, even when setting the maximum to be low, the driver will sometimes still run at a max frequency. It also will not respect settings for no_turbo.
This is due in part to the fact that the max cpu_frequency is defined in
as the turbo boosted frequency max. The acpi-cpufreq driver reports the proper frequency and the rules that are set are observed by the driver and cpu frequencies.