| Message ID | 20230118075210.447418-12-perry.yuan@amd.com |
|---|---|
| State | Superseded |
| Headers | show |
| Series | Implement AMD Pstate EPP Driver | expand |
On 1/18/2023 1:22 PM, Perry Yuan wrote: > 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> > Tested-by: Wyes Karny <wyes.karny@amd.com> > Reviewed-by: Mario Limonciello <mario.limonciello@amd.com> > Signed-off-by: Perry Yuan <perry.yuan@amd.com> Reviewed-by: Wyes Karny <wyes.karny@amd.com> > --- > Documentation/admin-guide/pm/amd-pstate.rst | 29 +++++++++++++++++++++ > 1 file changed, 29 insertions(+) > > 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`` > =============================================== >
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`` ===============================================