[PATCH 0/1][SRU][OEM-5.17/Unstable] Support AMD P-State cpufreq control mechanism

[You-Sheng Yang]

BugLink: https://bugs.launchpad.net/bugs/1956509

[Impact]

AMD P-State CPU performance scaling driver not yet supported on AMD Zen
based CPU series.

[Fix]

Mainline commits starting at commit d341db8f48ea ("x86/cpufeatures: Add
AMD Collaborative Processor Performance Control feature flag") from v5.17.

Even this committed, the defconfig will build it as module, and that
prevents AMD P-State driver from actually taking effect. Therefore an
additional fix to the kernel configs is necessary.

[Test Case]

$ sudo cpupower frequency-info
analyzing CPU 0:
  driver: amd-pstate
  CPUs which run at the same hardware frequency: 0
  CPUs which need to have their frequency coordinated by software: 0
  maximum transition latency: 131 us
  hardware limits: 400 MHz - 3.10 GHz
  available cpufreq governors: conservative ondemand userspace powersave
performance schedutil
  current policy: frequency should be within 1.60 GHz and 3.10 GHz.
                  The governor "ondemand" may decide which speed to use
                  within this range.
  current CPU frequency: Unable to call hardware
  current CPU frequency: 1.59 GHz (asserted by call to kernel)
  boost state support:
    Supported: yes
    Active: yes
    Boost States: 0
    Total States: 3
    Pstate-P0: 3100MHz
    Pstate-P1: 1800MHz
    Pstate-P2: 1600MHz

[Where problems could occur]

The CPPC feature is implemented in two ways depending on underlying HW
details for the APU/CPU:
* Dedicated MSR
* Shared memory

The metrics used to measure power/performance efficiency don't show any
improvement on the designs that use shared memory. They do show
improvements in the MSR designs.

So the code will only enable it by default on the MSR implementation.

[Other Info]

Althought the v5.17 kernel and newer should have already this committed,
an additional fix to the kernel configs is necessary, and
unstable/oem-5.17 are also nominated (in a separate thread for they don't
need other parts but the config).

You-Sheng Yang (1):
  UBUNTU: [Config] enable X86_AMD_PSTATE as built-in on amd64

 debian.master/config/annotations          | 1 +
 debian.master/config/config.common.ubuntu | 2 +-
 2 files changed, 2 insertions(+), 1 deletion(-)

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2.34.1