RE: [PATCH v9 13/13] Documentation: amd-pstate: introduce new global sysfs attributes

Yuan, Perry
2023-01-05T06:21:49Z

[AMD Official Use Only - General]

Hi Mario.

> -----Original Message-----
> From: Limonciello, Mario <Mario.Limonciello@amd.com>
> Sent: Wednesday, January 4, 2023 8:35 AM
> To: Yuan, Perry <Perry.Yuan@amd.com>; rafael.j.wysocki@intel.com; Huang,
> Ray <Ray.Huang@amd.com>; viresh.kumar@linaro.org
> Cc: Sharma, Deepak <Deepak.Sharma@amd.com>; Fontenot, Nathan
> <Nathan.Fontenot@amd.com>; Deucher, Alexander
> <Alexander.Deucher@amd.com>; Huang, Shimmer
> <Shimmer.Huang@amd.com>; Du, Xiaojian <Xiaojian.Du@amd.com>; Meng,
> Li (Jassmine) <Li.Meng@amd.com>; Karny, Wyes <Wyes.Karny@amd.com>;
> linux-pm@vger.kernel.org; linux-kernel@vger.kernel.org
> Subject: Re: [PATCH v9 13/13] Documentation: amd-pstate: introduce new
> global sysfs attributes
>
> On 12/25/2022 10:34, 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`
> >
> > Signed-off-by: Perry Yuan <perry.yuan@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 62744dae3c5f..5f6379475b32 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 cause
> > + the driver
>
> "will cause the driver to cause the driver to"?
>
> Presumably you mean just "will cause the driver to"
>
> With that fixed:
>
> Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>

Thanks for the review, will fix the words and pick up the RB tag in v10.

Perry.

>
> > + 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``
> > ===============================================
> >