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

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>

diff --git a/Documentation/admin-guide/pm/amd-pstate.rst b/Documentation/admin-guide/pm/amd-pstate.rst
index f8e7050..a95e2eb 100644 (file)
--- a/Documentation/admin-guide/pm/amd-pstate.rst
+++ b/Documentation/admin-guide/pm/amd-pstate.rst
@@ -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
 ===========================================

diff --git a/drivers/cpufreq/Kconfig.x86 b/drivers/cpufreq/Kconfig.x86
index 027e6ea..a9093cd 100644 (file)
--- a/drivers/cpufreq/Kconfig.x86
+++ b/drivers/cpufreq/Kconfig.x86
@@ -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

diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
index 9eb9c3f..62b5d99 100644 (file)
--- a/drivers/cpufreq/amd-pstate.c
+++ b/drivers/cpufreq/amd-pstate.c
@@ -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;
 
 /*