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Message-ID: <20221117071910.3347052-1-Perry.Yuan@amd.com>
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
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