Messages in this thread | | | Date | Mon, 19 Dec 2022 17:28:11 -0600 | Subject | Re: [PATCH v8 10/13] Documentation: amd-pstate: add amd pstate driver mode introduction | From | "Limonciello, Mario" <> |
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On 12/19/2022 00:40, Perry Yuan wrote: > From: Perry Yuan <Perry.Yuan@amd.com> > > 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 <Perry.Yuan@amd.com>
With nit fixed:
Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
> --- > 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 > ------------
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