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cpufreq/amd-pstate: Drop Kconfig option for dynamic EPP

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There are some performance issues being identified by dynamic EPP
and we don't want to have distributions turning it on by default
exposing them to users at this time.

Drop the kconfig option, and require an explicit opt in from kernel
command line or runtime sysfs option to turn it on.

Reported-by: Viktor Jägersküpper <viktor_jaegerskuepper@freenet.de>
Closes: https://lore.kernel.org/linux-pm/14a87c99-785c-4b16-bfce-35ecbf053448@freenet.de/
Reported-by: Stuart Meckle <stuartmeckle@gmail.com>
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=221473
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Reviewed-by: K Prateek Nayak <kprateek.nayak@amd.com>
Link: https://lore.kernel.org/r/20260512221947.1652988-1-mario.limonciello@amd.com
(fix sysfs file path)
Signed-off-by: Mario Limonciello (AMD) <superm1@kernel.org>
This commit is contained in:
Mario Limonciello 2026-05-12 17:19:47 -05:00 committed by Mario Limonciello (AMD)
parent f9f16835d4
commit e4e9b7b38d
3 changed files with 5 additions and 22 deletions
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11
Documentation/admin-guide/pm/amd-pstate.rst
View File

@ -358,9 +358,9 @@ Dynamic energy performance profile
The amd-pstate driver supports dynamically selecting the energy performance
profile based on whether the machine is running on AC or DC power.
Whether this behavior is enabled by default depends on the kernel
config option `CONFIG_X86_AMD_PSTATE_DYNAMIC_EPP`. This behavior can also be overridden
at runtime by the sysfs file ``/sys/devices/system/cpu/cpufreq/policyX/dynamic_epp``.
Whether this behavior is enabled by default depends on the kernel command line option
``amd_dynamic_epp`` is set. This behavior can also be overridden
at runtime by the sysfs file ``/sys/devices/system/cpu/amd_pstate/dynamic_epp``.
When set to enabled, the driver will select a different energy performance
profile when the machine is running on battery or AC power. The driver will
@ -485,9 +485,8 @@ kernel parameter ``amd_prefcore=disable``.
``amd_dynamic_epp``
When AMD pstate is in auto mode, dynamic EPP will control whether the kernel
autonomously changes the EPP mode. The default is configured by
``CONFIG_X86_AMD_PSTATE_DYNAMIC_EPP`` but can be explicitly enabled with
``amd_dynamic_epp=enable`` or disabled with ``amd_dynamic_epp=disable``.
autonomously changes the EPP mode. The default is disabled. It can be enabled
with the kernel parameter ``amd_dynamic_epp=enable``.
User Space Interface in ``sysfs`` - General
===========================================

12
drivers/cpufreq/Kconfig.x86
View File

@ -70,18 +70,6 @@ config X86_AMD_PSTATE_DEFAULT_MODE
For details, take a look at:
<file:Documentation/admin-guide/pm/amd-pstate.rst>.
config X86_AMD_PSTATE_DYNAMIC_EPP
bool "AMD Processor P-State dynamic EPP support"
depends on X86_AMD_PSTATE
default n
help
Allow the kernel to dynamically change the energy performance
value from events like ACPI platform profile and AC adapter plug
events.
This feature can also be changed at runtime, this configuration
option only sets the kernel default value behavior.
config X86_AMD_PSTATE_UT
tristate "selftest for AMD Processor P-State driver"
depends on X86 && ACPI_PROCESSOR

4
drivers/cpufreq/amd-pstate.c
View File

@ -87,11 +87,7 @@ static struct cpufreq_driver amd_pstate_driver;
static struct cpufreq_driver amd_pstate_epp_driver;
static int cppc_state = AMD_PSTATE_UNDEFINED;
static bool amd_pstate_prefcore = true;
#ifdef CONFIG_X86_AMD_PSTATE_DYNAMIC_EPP
static bool dynamic_epp = CONFIG_X86_AMD_PSTATE_DYNAMIC_EPP;
#else
static bool dynamic_epp;
#endif
static struct quirk_entry *quirks;
/*