Why the amd p-state isn't available after enabling and compiling it in the kernel?

Question

Im trying to test the amd p-state recently released , but after compiling the whole kernel, or applying the respective patch the amd-pstate isn't available for the system.

On the source dir:

ls  ~/linux-amd-pstate-dev-v5/drivers/cpufreq/amd*

amd-pstate-trace.c           
amd-pstate-trace.h           
amd-pstate.c  

after enabling the relevant parts in the config file

Processor type and features  --->
  [*] Symmetric multi-processing support
  [*] Support x2apic
  [*] AMD ACPI2Platform devices support
  Processor family (Opteron/Athlon64/Hammer/K8)  --->
    (X) Opteron/Athlon64/Hammer/K8
  [*] Supported processor vendors  --->
    [*]   Support AMD processors (NEW)
  [*] SMT (Hyperthreading) scheduler support
  [*] Multi-core scheduler support
  [*] Machine Check / overheating reporting
  [*]   AMD MCE features
  Performance monitoring  --->
    <*> AMD Processor Power Reporting Mechanism
  [*]   AMD microcode loading support
Power management and ACPI options  --->
  CPU Frequency scaling  --->
      Default CPUFreq governor (ondemand)  --->
      CPU Frequency scaling drivers
         [*]   AMD Processor P-state driver


    <*>   ACPI Processor P-States driver
    [ /*]     Legacy cpb sysfs knob support for AMD CPUs
    < >   AMD Opteron/Athlon64 PowerNow!
    <*>   AMD frequency sensitivity feedback powersave bias
Device Drivers  --->
  Generic Driver Options --->
    (amd-ucode/microcode_amd_fam17h.bin) External firmware blobs to build into the kernel binary
    (/lib/firmware) Firware blobs root directory
  [*] IOMMU Hardware Support  --->
    [*]   AMD IOMMU support
    <*>     AMD IOMMU Version 2 driver

And after compiling the kernel, the driver used by cpufreq is

driver: acpi-cpufreq  

I have blacklisted acpi-cpufreq and added to the loadline of the kernel at boot. And the amd-pstate is inserted using

modprobe amd-pstate  

And it seems to be loading but there is nothing on the terminal.

Then how can compile and enable these module. I have a ton of ryzens cpus and perhaps going to buy more, so it could be interesting to save a bit of power. Thanks.

Answer 1

Have you tried using amd_pstate.enable=1 as GRUB parameter?

source: https://www.phoronix.com/forums/forum/hardware/processors-memory/1297365-amd-p-state-cpu-frequency-control-driver-revised-a-6th-time?p=1297378#post1297378