From: Perry Yuan <[email protected]>
Introduce ``amd-pstate`` CPPC has two operation modes:
* CPPC Autonomous (active) mode
* CPPC non-autonomous (passive) mode.
active mode and passive mode can be chosen by different kernel parameters.
Signed-off-by: Perry Yuan <[email protected]>
---
Documentation/admin-guide/pm/amd-pstate.rst | 26 +++++++++++++++++++--
1 file changed, 24 insertions(+), 2 deletions(-)
diff --git a/Documentation/admin-guide/pm/amd-pstate.rst b/Documentation/admin-guide/pm/amd-pstate.rst
index 33ab8ec8fc2f..62744dae3c5f 100644
--- a/Documentation/admin-guide/pm/amd-pstate.rst
+++ b/Documentation/admin-guide/pm/amd-pstate.rst
@@ -299,8 +299,30 @@ module which supports the new AMD P-States mechanism on most of the future AMD
platforms. The AMD P-States mechanism is the more performance and energy
efficiency frequency management method on AMD processors.
-Kernel Module Options for ``amd-pstate``
-=========================================
+
+AMD Pstate Driver Operation Modes
+=================================
+
+``amd_pstate`` CPPC has two operation modes: CPPC Autonomous(active) mode and
+CPPC non-autonomous(passive) mode.
+active mode and passive mode can be chosen by different kernel parameters.
+When in Autonomous mode, CPPC ignores requests done in the Desired Performance
+Target register and takes into account only the values set to the Minimum requested
+performance, Maximum requested performance, and Energy Performance Preference
+registers. When Autonomous is disabled, it only considers the Desired Performance Target.
+
+Active Mode
+------------
+
+``amd_pstate=active``
+
+This is the low-level firmware control mode which is implemented by ``amd_pstate_epp``
+driver with ``amd_pstate=active`` passed to the kernel in the command line.
+In this mode, ``amd_pstate_epp`` driver provides a hint to the hardware if software
+wants to bias toward performance (0x0) or energy efficiency (0xff) to the CPPC firmware.
+then CPPC power algorithm will calculate the runtime workload and adjust the realtime
+cores frequency according to the power supply and thermal, core voltage and some other
+hardware conditions.
Passive Mode
------------
--
2.34.1
On 12/19/2022 00:40, Perry Yuan wrote:
> From: Perry Yuan <[email protected]>
>
> Introduce ``amd-pstate`` CPPC has two operation modes:
Drop the word Introduce.
> * CPPC Autonomous (active) mode
> * CPPC non-autonomous (passive) mode.
> active mode and passive mode can be chosen by different kernel parameters.
>
> Signed-off-by: Perry Yuan <[email protected]>
With nit fixed:
Reviewed-by: Mario Limonciello <[email protected]>
> ---
> Documentation/admin-guide/pm/amd-pstate.rst | 26 +++++++++++++++++++--
> 1 file changed, 24 insertions(+), 2 deletions(-)
>
> diff --git a/Documentation/admin-guide/pm/amd-pstate.rst b/Documentation/admin-guide/pm/amd-pstate.rst
> index 33ab8ec8fc2f..62744dae3c5f 100644
> --- a/Documentation/admin-guide/pm/amd-pstate.rst
> +++ b/Documentation/admin-guide/pm/amd-pstate.rst
> @@ -299,8 +299,30 @@ module which supports the new AMD P-States mechanism on most of the future AMD
> platforms. The AMD P-States mechanism is the more performance and energy
> efficiency frequency management method on AMD processors.
>
> -Kernel Module Options for ``amd-pstate``
> -=========================================
> +
> +AMD Pstate Driver Operation Modes
> +=================================
> +
> +``amd_pstate`` CPPC has two operation modes: CPPC Autonomous(active) mode and
> +CPPC non-autonomous(passive) mode.
> +active mode and passive mode can be chosen by different kernel parameters.
> +When in Autonomous mode, CPPC ignores requests done in the Desired Performance
> +Target register and takes into account only the values set to the Minimum requested
> +performance, Maximum requested performance, and Energy Performance Preference
> +registers. When Autonomous is disabled, it only considers the Desired Performance Target.
> +
> +Active Mode
> +------------
> +
> +``amd_pstate=active``
> +
> +This is the low-level firmware control mode which is implemented by ``amd_pstate_epp``
> +driver with ``amd_pstate=active`` passed to the kernel in the command line.
> +In this mode, ``amd_pstate_epp`` driver provides a hint to the hardware if software
> +wants to bias toward performance (0x0) or energy efficiency (0xff) to the CPPC firmware.
> +then CPPC power algorithm will calculate the runtime workload and adjust the realtime
> +cores frequency according to the power supply and thermal, core voltage and some other
> +hardware conditions.
>
> Passive Mode
> ------------