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| author | Perry Yuan <perry.yuan@amd.com> | 2023-01-31 17:00:16 +0800 |
|---|---|---|
| committer | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2023-02-03 21:59:42 +0100 |
| commit | b9e6a2d47b2565eb450d3ee900fba49cc9b25cbd (patch) | |
| tree | 47b22aefaee9102e1e994b09305dcb89bc023bb9 | |
| parent | 3ec32b6d17c5b229c6f5d05849932af1f0c6f523 (diff) | |
Documentation: amd-pstate: introduce new global sysfs attributes
The amd-pstate driver supports switching working modes at runtime.
Users can view and change modes by interacting with the "status" sysfs
attribute.
1) check driver mode:
$ cat /sys/devices/system/cpu/amd-pstate/status
2) switch mode:
`# echo "passive" | sudo tee /sys/devices/system/cpu/amd-pstate/status`
or
`# echo "active" | sudo tee /sys/devices/system/cpu/amd-pstate/status`
Acked-by: Huang Rui <ray.huang@amd.com>
Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
Reviewed-by: Wyes Karny <wyes.karny@amd.com>
Tested-by: Wyes Karny <wyes.karny@amd.com>
Signed-off-by: Perry Yuan <perry.yuan@amd.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
| -rw-r--r-- | Documentation/admin-guide/pm/amd-pstate.rst | 29 |
1 files changed, 29 insertions, 0 deletions
diff --git a/Documentation/admin-guide/pm/amd-pstate.rst b/Documentation/admin-guide/pm/amd-pstate.rst index b6aee69f564f..5304adf2fc2f 100644 --- a/Documentation/admin-guide/pm/amd-pstate.rst +++ b/Documentation/admin-guide/pm/amd-pstate.rst @@ -339,6 +339,35 @@ processor must provide at least nominal performance requested and go higher if c operating conditions allow. +User Space Interface in ``sysfs`` +================================= + +Global Attributes +----------------- + +``amd-pstate`` exposes several global attributes (files) in ``sysfs`` to +control its functionality at the system level. They are located in the +``/sys/devices/system/cpu/amd-pstate/`` directory and affect all CPUs. + +``status`` + Operation mode of the driver: "active", "passive" or "disable". + + "active" + The driver is functional and in the ``active mode`` + + "passive" + The driver is functional and in the ``passive mode`` + + "disable" + The driver is unregistered and not functional now. + + This attribute can be written to in order to change the driver's + operation mode or to unregister it. The string written to it must be + one of the possible values of it and, if successful, writing one of + these values to the sysfs file will cause the driver to switch over + to the operation mode represented by that string - or to be + unregistered in the "disable" case. + ``cpupower`` tool support for ``amd-pstate`` =============================================== |