Re: [PATCH v6 2/5] cpufreq/amd-pstate: add kernel command line to override dynamic epp

[Gautham R. Shenoy]

Hello Mario,

On Sun, Mar 29, 2026 at 03:38:08PM -0500, Mario Limonciello (AMD) wrote:
> 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@xxxxxxxxxx>

This looks good to me.

Reviewed-by: Gautham R. Shenoy <gautham.shenoy@xxxxxxx>


-- 
Thanks and Regards
gautham.
> ---
> v5->v6:
>  * Fix the amd_dynamic_epp kernel parameter name in amd-pstate.rst
> ---
>  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: <a>,<b>
> diff --git a/Documentation/admin-guide/pm/amd-pstate.rst b/Documentation/admin-guide/pm/amd-pstate.rst
> index 0e4355fe13558..210207d301aa5 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 2e3fb1fd280a0..e96f1da5c7b38 100644
> --- a/drivers/cpufreq/amd-pstate.c
> +++ b/drivers/cpufreq/amd-pstate.c
> @@ -2224,8 +2224,19 @@ 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@xxxxxxx>");
>  MODULE_DESCRIPTION("AMD Processor P-state Frequency Driver");
> -- 
> 2.43.0
>