drivers/cpufreq/Kconfig.x86 v5.13-rc1

X86_INTEL_PSTATE

Intel P state control

This driver provides a P state for Intel core processors.
The driver implements an internal governor and will become
the scaling driver and governor for Sandy bridge processors.

When this driver is enabled it will become the preferred
scaling driver for Sandy bridge processors.

If in doubt, say N.

X86_PCC_CPUFREQ

Processor Clocking Control interface driver

This driver adds support for the PCC interface.

For details, take a look at:
<file:Documentation/admin-guide/pm/cpufreq_drivers.rst>.

To compile this driver as a module, choose M here: the
module will be called pcc-cpufreq.

If in doubt, say N.

X86_ACPI_CPUFREQ

ACPI Processor P-States driver

This driver adds a CPUFreq driver which utilizes the ACPI
Processor Performance States.
This driver also supports Intel Enhanced Speedstep and newer
AMD CPUs.

To compile this driver as a module, choose M here: the
module will be called acpi-cpufreq.

For details, take a look at <file:Documentation/cpu-freq/>.

If in doubt, say N.

X86_ACPI_CPUFREQ_CPB

Legacy cpb sysfs knob support for AMD CPUs

The powernow-k8 driver used to provide a sysfs knob called "cpb"
to disable the Core Performance Boosting feature of AMD CPUs. This
file has now been superseded by the more generic "boost" entry.

By enabling this option the acpi_cpufreq driver provides the old
entry in addition to the new boost ones, for compatibility reasons.

ELAN_CPUFREQ

AMD Elan SC400 and SC410

This adds the CPUFreq driver for AMD Elan SC400 and SC410
processors.

You need to specify the processor maximum speed as boot
parameter: elanfreq=maxspeed (in kHz) or as module
parameter "max_freq".

For details, take a look at <file:Documentation/cpu-freq/>.

If in doubt, say N.

SC520_CPUFREQ

AMD Elan SC520

This adds the CPUFreq driver for AMD Elan SC520 processor.

For details, take a look at <file:Documentation/cpu-freq/>.

If in doubt, say N.


X86_POWERNOW_K6

AMD Mobile K6-2/K6-3 PowerNow!

This adds the CPUFreq driver for mobile AMD K6-2+ and mobile
AMD K6-3+ processors.

For details, take a look at <file:Documentation/cpu-freq/>.

If in doubt, say N.

X86_POWERNOW_K7

AMD Mobile Athlon/Duron PowerNow!

This adds the CPUFreq driver for mobile AMD K7 mobile processors.

For details, take a look at <file:Documentation/cpu-freq/>.

If in doubt, say N.

X86_POWERNOW_K8

AMD Opteron/Athlon64 PowerNow!

This adds the CPUFreq driver for K8/early Opteron/Athlon64 processors.
Support for K10 and newer processors is now in acpi-cpufreq.

To compile this driver as a module, choose M here: the
module will be called powernow-k8.

For details, take a look at <file:Documentation/cpu-freq/>.

X86_AMD_FREQ_SENSITIVITY

AMD frequency sensitivity feedback powersave bias

This adds AMD-specific powersave bias function to the ondemand
governor, which allows it to make more power-conscious frequency
change decisions based on feedback from hardware (available on AMD
Family 16h and above).

Hardware feedback tells software how "sensitive" to frequency changes
the CPUs' workloads are. CPU-bound workloads will be more sensitive
-- they will perform better as frequency increases. Memory/IO-bound
workloads will be less sensitive -- they will not necessarily perform
better as frequency increases.

If in doubt, say N.

X86_GX_SUSPMOD

Cyrix MediaGX/NatSemi Geode Suspend Modulation

This add the CPUFreq driver for NatSemi Geode processors which
support suspend modulation.

For details, take a look at <file:Documentation/cpu-freq/>.

If in doubt, say N.

X86_SPEEDSTEP_CENTRINO

Intel Enhanced SpeedStep (deprecated)

This is deprecated and this functionality is now merged into
acpi_cpufreq (X86_ACPI_CPUFREQ). Use that driver instead of
speedstep_centrino.
This adds the CPUFreq driver for Enhanced SpeedStep enabled
mobile CPUs.  This means Intel Pentium M (Centrino) CPUs
or 64bit enabled Intel Xeons.

To compile this driver as a module, choose M here: the
module will be called speedstep-centrino.

For details, take a look at <file:Documentation/cpu-freq/>.

If in doubt, say N.

X86_SPEEDSTEP_CENTRINO_TABLE

Built-in tables for Banias CPUs

Use built-in tables for Banias CPUs if ACPI encoding
is not available.

If in doubt, say N.

X86_SPEEDSTEP_ICH

Intel Speedstep on ICH-M chipsets (ioport interface)

This adds the CPUFreq driver for certain mobile Intel Pentium III
(Coppermine), all mobile Intel Pentium III-M (Tualatin) and all
mobile Intel Pentium 4 P4-M on systems which have an Intel ICH2,
ICH3 or ICH4 southbridge.

For details, take a look at <file:Documentation/cpu-freq/>.

If in doubt, say N.

X86_SPEEDSTEP_SMI

Intel SpeedStep on 440BX/ZX/MX chipsets (SMI interface)

This adds the CPUFreq driver for certain mobile Intel Pentium III
(Coppermine), all mobile Intel Pentium III-M (Tualatin)
on systems which have an Intel 440BX/ZX/MX southbridge.

For details, take a look at <file:Documentation/cpu-freq/>.

If in doubt, say N.

X86_P4_CLOCKMOD

Intel Pentium 4 clock modulation

This adds the CPUFreq driver for Intel Pentium 4 / XEON
processors.  When enabled it will lower CPU temperature by skipping
clocks.

This driver should be only used in exceptional
circumstances when very low power is needed because it causes severe
slowdowns and noticeable latencies.  Normally Speedstep should be used
instead.

To compile this driver as a module, choose M here: the
module will be called p4-clockmod.

For details, take a look at <file:Documentation/cpu-freq/>.

Unless you are absolutely sure say N.

X86_CPUFREQ_NFORCE2

nVidia nForce2 FSB changing

This adds the CPUFreq driver for FSB changing on nVidia nForce2
platforms.

For details, take a look at <file:Documentation/cpu-freq/>.

If in doubt, say N.

X86_LONGRUN

Transmeta LongRun

This adds the CPUFreq driver for Transmeta Crusoe and Efficeon processors
which support LongRun.

For details, take a look at <file:Documentation/cpu-freq/>.

If in doubt, say N.

X86_LONGHAUL

VIA Cyrix III Longhaul

This adds the CPUFreq driver for VIA Samuel/CyrixIII,
VIA Cyrix Samuel/C3, VIA Cyrix Ezra and VIA Cyrix Ezra-T
processors.

For details, take a look at <file:Documentation/cpu-freq/>.

If in doubt, say N.

X86_E_POWERSAVER

VIA C7 Enhanced PowerSaver (DANGEROUS)

This adds the CPUFreq driver for VIA C7 processors.  However, this driver
does not have any safeguards to prevent operating the CPU out of spec
and is thus considered dangerous.  Please use the regular ACPI cpufreq
driver, enabled by CONFIG_X86_ACPI_CPUFREQ.

If in doubt, say N.

shared options

X86_SPEEDSTEP_RELAXED_CAP_CHECK

Relaxed speedstep capability checks

Don't perform all checks for a speedstep capable system which would
normally be done. Some ancient or strange systems, though speedstep
capable, don't always indicate that they are speedstep capable. This
option lets the probing code bypass some of those checks if the
parameter "relaxed_check=1" is passed to the module.