[PATCH v7 2/5] cpufreq/amd-pstate: add kernel command line to override dynamic epp

Mario Limonciello (AMD)
2026-03-31T19:59:17Z

Add `amd_dynamic_epp=enable` and `amd_dynamic_epp=disable` to override
the kernel configuration option `CONFIG_X86_AMD_PSTATE_DYNAMIC_EPP`
locally.

Signed-off-by: Mario Limonciello (AMD) <superm1@kernel.org>
Reviewed-by: Gautham R. Shenoy <gautham.shenoy@amd.com>
---
Documentation/admin-guide/kernel-parameters.txt | 7 +++++++
Documentation/admin-guide/pm/amd-pstate.rst | 7 +++++++
drivers/cpufreq/amd-pstate.c | 11 +++++++++++
3 files changed, 25 insertions(+)

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 03a550630644f..9552819051cd8 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -493,6 +493,13 @@ Kernel parameters
disable
Disable amd-pstate preferred core.

+ amd_dynamic_epp=
+ [X86]
+ disable
+ Disable amd-pstate dynamic EPP.
+ enable
+ Enable amd-pstate dynamic EPP.
+
amijoy.map= [HW,JOY] Amiga joystick support
Map of devices attached to JOY0DAT and JOY1DAT
Format: ,
diff --git a/Documentation/admin-guide/pm/amd-pstate.rst b/Documentation/admin-guide/pm/amd-pstate.rst
index bb1341763882b..01e6ab10f996e 100644
--- a/Documentation/admin-guide/pm/amd-pstate.rst
+++ b/Documentation/admin-guide/pm/amd-pstate.rst
@@ -474,6 +474,13 @@ For systems that support ``amd-pstate`` preferred core, the core rankings will
always be advertised by the platform. But OS can choose to ignore that via the
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``.
+
User Space Interface in ``sysfs`` - General
===========================================

diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
index d3c8eaab88286..de22d9bd28cc6 100644
--- a/drivers/cpufreq/amd-pstate.c
+++ b/drivers/cpufreq/amd-pstate.c
@@ -2230,8 +2230,19 @@ static int __init amd_prefcore_param(char *str)
return 0;
}

+static int __init amd_dynamic_epp_param(char *str)
+{
+ if (!strcmp(str, "disable"))
+ dynamic_epp = false;
+ if (!strcmp(str, "enable"))
+ dynamic_epp = true;
+
+ return 0;
+}
+
early_param("amd_pstate", amd_pstate_param);
early_param("amd_prefcore", amd_prefcore_param);
+early_param("amd_dynamic_epp", amd_dynamic_epp_param);

MODULE_AUTHOR("Huang Rui <ray.huang@amd.com>");
MODULE_DESCRIPTION("AMD Processor P-state Frequency Driver");
--
2.43.0