linux.git/Documentation/admin-guide/pm/amd-pstate.rst, branch master

cpufreq/amd-pstate: Drop Kconfig option for dynamic EPP

2026-05-14T13:47:48+00:00

There are some performance issues being identified by dynamic EPP
and we don't want to have distributions turning it on by default
exposing them to users at this time.

Drop the kconfig option, and require an explicit opt in from kernel
command line or runtime sysfs option to turn it on.

Reported-by: Viktor Jägersküpper 
Closes: https://lore.kernel.org/linux-pm/14a87c99-785c-4b16-bfce-35ecbf053448@freenet.de/
Reported-by: Stuart Meckle 
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=221473
Signed-off-by: Mario Limonciello 
Reviewed-by: K Prateek Nayak 
Link: https://lore.kernel.org/r/20260512221947.1652988-1-mario.limonciello@amd.com
(fix sysfs file path)
Signed-off-by: Mario Limonciello (AMD)

cpufreq/amd-pstate: Add support for raw EPP writes

2026-04-02T16:29:25+00:00

The energy performance preference field of the CPPC request MSR
supports values from 0 to 255, but the strings only offer 4 values.

The other values are useful for tuning the performance of some
workloads.

Add support for writing the raw energy performance preference value
to the sysfs file.  If the last value written was an integer then
an integer will be returned.  If the last value written was a string
then a string will be returned.

Reviewed-by: Gautham R. Shenoy 
Signed-off-by: Mario Limonciello (AMD)

cpufreq/amd-pstate: Add support for platform profile class

2026-04-02T16:29:15+00:00

The platform profile core allows multiple drivers and devices to
register platform profile support.

When the legacy platform profile interface is used all drivers will
adjust the platform profile as well.

Add support for registering every CPU with the platform profile handler
when dynamic EPP is enabled.

The end result will be that changing the platform profile will modify
EPP accordingly.

Reviewed-by: Gautham R. Shenoy 
Signed-off-by: Mario Limonciello (AMD)

cpufreq/amd-pstate: add kernel command line to override dynamic epp

2026-04-02T16:29:11+00:00

Add `amd_dynamic_epp=enable` and `amd_dynamic_epp=disable` to override
the kernel configuration option `CONFIG_X86_AMD_PSTATE_DYNAMIC_EPP`
locally.

Signed-off-by: Mario Limonciello (AMD) 
Reviewed-by: Gautham R. Shenoy 
Signed-off-by: Mario Limonciello (AMD)

cpufreq/amd-pstate: Add dynamic energy performance preference

2026-04-02T16:29:02+00:00

Dynamic energy performance preference changes the EPP profile based on
whether the machine is running on AC or DC power.

A notification chain from the power supply core is used to adjust EPP
values on plug in or plug out events.

When enabled, the driver exposes a sysfs toggle for dynamic EPP, blocks
manual writes to energy_performance_preference while it "owns" the EPP
updates.

For non-server systems:
    * the default EPP for AC mode is `performance`.
    * the default EPP for DC mode is `balance_performance`.

For server systems dynamic EPP is mostly a no-op.

Reviewed-by: Gautham R. Shenoy 
Signed-off-by: Mario Limonciello (AMD)

Documentation: amd-pstate: fix dead links in the reference section

2026-04-02T16:28:58+00:00

The links for AMD64 Architecture Programmer's Manual and PPR for AMD
Family 19h Model 51h, Revision A1 Processors redirect to a generic page.
Update the links to the working ones.

Signed-off-by: Ninad Naik 
Link: https://lore.kernel.org/r/20260330190855.1115304-1-ninadnaik07@gmail.com
Acked-by: Mario Limonciello (AMD) 
Signed-off-by: Mario Limonciello (AMD)

Documentation/amd-pstate: Add documentation for amd_pstate_floor_{freq,count}

2026-04-02T16:28:51+00:00

Add documentation for the sysfs files
/sys/devices/system/cpu/cpufreq/policy*/amd_pstate_floor_freq
and
/sys/devices/system/cpu/cpufreq/policy*/amd_pstate_floor_count.

Reviewed-by: Mario Limonciello (AMD) 
Signed-off-by: Gautham R. Shenoy 
Signed-off-by: Mario Limonciello (AMD)

Documentation/amd-pstate: List amd_pstate_prefcore_ranking sysfs file

2026-04-02T16:28:48+00:00

Add the missing amd_pstate_prefcore_ranking filenames in the sysfs
listing example leading to the descriptions of these
parameters. Clarify when will the file be visible.

Fixes: 15a2b764ea7c ("amd-pstate: Add missing documentation for `amd_pstate_prefcore_ranking`")
Reviewed-by: Mario Limonciello (AMD) 
Signed-off-by: Gautham R. Shenoy 
Signed-off-by: Mario Limonciello (AMD)

Documentation/amd-pstate: List amd_pstate_hw_prefcore sysfs file

2026-04-02T16:28:44+00:00

Add the missing amd_pstate_hw_prefcore filenames in the sysfs listing
example leading to the descriptions of these parameters. Clarify when
will the file be visible.

Fixes: b96b82d1af7f ("cpufreq: amd-pstate: Add documentation for `amd_pstate_hw_prefcore`")
Reviewed-by: Mario Limonciello (AMD) 
Signed-off-by: Gautham R. Shenoy 
Signed-off-by: Mario Limonciello (AMD)

Documentation: amd-pstate:fix minimum performance state label error

2025-07-16T19:55:58+00:00

In the AMD P-States Performance Scale diagram, the labels for "Max Perf"
and "Lowest Perf" were incorrectly used to define the range for
"Desired Perf".The "Desired performance target" should be bounded by the
"Maximum requested performance" and the "Minimum requested performance",
which corresponds to "Max Perf" and "Min Perf", respectively.

Signed-off-by: Shouye Liu 
Reviewed-by: Mario Limonciello 
Link: https://lore.kernel.org/r/20250522070140.17557-1-shouyeliu@gmail.com
Signed-off-by: Mario Limonciello