cpufreq/amd-pstate: add kernel command line to override dynamic epp

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>
Signed-off-by: Mario Limonciello (AMD) <superm1@kernel.org>

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 03a550630644f43d36b69ae79e6d66f42d75426d..9552819051cd8a1e900244a4fa7811f9b6e76a74 100644 (file)
--- 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: <a>,<b>

diff --git a/Documentation/admin-guide/pm/amd-pstate.rst b/Documentation/admin-guide/pm/amd-pstate.rst
index bb1341763882b130604bd2029b7a2e24dc68e3f0..01e6ab10f996edbfbe0c2f4252a0c9224e0ff501 100644 (file)
--- 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 379e7dd442522dad363bd8655862e8cee2543f7e..301e603e49660d9ec84066c2471de50d0f9faf27 100644 (file)
--- a/drivers/cpufreq/amd-pstate.c
+++ b/drivers/cpufreq/amd-pstate.c
@@ -2227,8 +2227,19 @@ 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");