linux-kernel - [PATCH v2 0/5] AMD Pstate driver Urgent Change

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Date:   Thu, 17 Nov 2022 15:19:05 +0800
From:   Perry Yuan <Perry.Yuan@....com>
To:     <rafael.j.wysocki@...el.com>, <ray.huang@....com>,
        <viresh.kumar@...aro.org>, <Mario.Limonciello@....com>
CC:     <Nathan.Fontenot@....com>, <Alexander.Deucher@....com>,
        <Deepak.Sharma@....com>, <Shimmer.Huang@....com>,
        <Li.Meng@....com>, <Xiaojian.Du@....com>, <wyes.karny@....com>,
        <gautham.shenoy@....com>, <ananth.narayan@....com>,
        <linux-pm@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        Perry Yuan <Perry.Yuan@....com>
Subject: [PATCH v2 0/5] AMD Pstate driver Urgent Change

The patchset changed amd-pstate driver as built-in type to resolve the
driver loading sequence problem, otherwise the acpi-cpufreq driver will
be loaded as the default cpufreq scaling driver instead of amd-pstate.

Some new kernel parameters are added to allow user to disable pstate driver
and load driver with passive mode which use governors to do the
frequency scaling control.

* `amd_pstate=disabled` or no parameters will not load pstate driver.
* `amd_pstate=passive` will load pstate driver with passive mode.

Set the `amd_pstate` driver disabled by default because of performance
degradation on a number of AMD ASICs in the passive mode driver,
especially the shared memory support processors.

EPP support for the amd_pstate driver is under review. With EPP support,
the said performance issue is resolved. Once that gets upstream,
the `active` mode amd_pstate_epp driver may be enabled by default.

Changes from v1:
 * fix commit info in v1 patch PATCH 4/5 
 * pick up Reviewed-by flag of Gautham R. Shenoy 
 * pick up Tested-by flag of  Wyes Karny 

Perry Yuan (4):
  cpufreq: amd-pstate: change amd-pstate driver to be built-in type
  cpufreq: amd-pstate: add amd-pstate driver parameter for mode
    selection
  Documentation: amd-pstate: add driver working mode introduction
  Documentation: add amd-pstate kernel command line options

Wyes Karny (1):
  cpufreq: amd-pstate: cpufreq: amd-pstate: reset MSR_AMD_PERF_CTL
    register at init

 .../admin-guide/kernel-parameters.txt         | 11 +++++
 Documentation/admin-guide/pm/amd-pstate.rst   | 30 +++++-------
 drivers/cpufreq/Kconfig.x86                   |  2 +-
 drivers/cpufreq/amd-pstate.c                  | 49 +++++++++++++------
 4 files changed, 59 insertions(+), 33 deletions(-)

-- 
2.25.1