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authorLinus Torvalds <torvalds@linux-foundation.org>2026-04-14 05:47:52 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2026-04-14 05:47:52 +0300
commitd7c8087a9cd8979d70edfe7c7feda9423feae3ab (patch)
tree09a9885768964f8e6cc8e5c07681faafd1215c05 /Documentation
parent2e31b16101834bdc0b720967845d6a0a309cf27b (diff)
parentd923f70e37310fe613883a3a4c2ea2f31246253b (diff)
downloadlinux-d7c8087a9cd8979d70edfe7c7feda9423feae3ab.tar.xz
Merge tag 'pm-7.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
Pull power management updates from Rafael Wysocki: "Once again, cpufreq is the most active development area, mostly because of the new feature additions and documentation updates in the amd-pstate driver, but there are also changes in the cpufreq core related to boost support and other assorted updates elsewhere. Next up are power capping changes due to the major cleanup of the Intel RAPL driver. On the cpuidle front, a new C-states table for Intel Panther Lake is added to the intel_idle driver, the stopped tick handling in the menu and teo governors is updated, and there are a couple of cleanups. Apart from the above, support for Tegra114 is added to devfreq and there are assorted cleanups of that code, there are also two updates of the operating performance points (OPP) library, two minor updates related to hibernation, and cpupower utility man pages updates and cleanups. Specifics: - Update qcom-hw DT bindings to include Eliza hardware (Abel Vesa) - Update cpufreq-dt-platdev blocklist (Faruque Ansari) - Minor updates to driver and dt-bindings for Tegra (Thierry Reding, Rosen Penev) - Add MAINTAINERS entry for CPPC driver (Viresh Kumar) - Add support for new features: CPPC performance priority, Dynamic EPP, Raw EPP, and new unit tests for them to amd-pstate (Gautham Shenoy, Mario Limonciello) - Fix sysfs files being present when HW missing and broken/outdated documentation in the amd-pstate driver (Ninad Naik, Gautham Shenoy) - Pass the policy to cpufreq_driver->adjust_perf() to avoid using cpufreq_cpu_get() in the .adjust_perf() callback in amd-pstate which leads to a scheduling-while-atomic bug (K Prateek Nayak) - Clean up dead code in Kconfig for cpufreq (Julian Braha) - Remove max_freq_req update for pre-existing cpufreq policy and add a boost_freq_req QoS request to save the boost constraint instead of overwriting the last scaling_max_freq constraint (Pierre Gondois) - Embed cpufreq QoS freq_req objects in cpufreq policy so they all are allocated in one go along with the policy to simplify lifetime rules and avoid error handling issues (Viresh Kumar) - Use DMI max speed when CPPC is unavailable in the acpi-cpufreq scaling driver (Henry Tseng) - Switch policy_is_shared() in cpufreq to using cpumask_nth() instead of cpumask_weight() because the former is more efficient (Yury Norov) - Use sysfs_emit() in sysfs show functions for cpufreq governor attributes (Thorsten Blum) - Update intel_pstate to stop returning an error when "off" is written to its status sysfs attribute while the driver is already off (Fabio De Francesco) - Include current frequency in the debug message printed by __cpufreq_driver_target() (Pengjie Zhang) - Refine stopped tick handling in the menu cpuidle governor and rearrange stopped tick handling in the teo cpuidle governor (Rafael Wysocki) - Add Panther Lake C-states table to the intel_idle driver (Artem Bityutskiy) - Clean up dead dependencies on CPU_IDLE in Kconfig (Julian Braha) - Simplify cpuidle_register_device() with guard() (Huisong Li) - Use performance level if available to distinguish between rates in OPP debugfs (Manivannan Sadhasivam) - Fix scoped_guard in dev_pm_opp_xlate_required_opp() (Viresh Kumar) - Return -ENODATA if the snapshot image is not loaded (Alberto Garcia) - Remove inclusion of crypto/hash.h from hibernate_64.c on x86 (Eric Biggers) - Clean up and rearrange the intel_rapl power capping driver to make the respective interface drivers (TPMI, MSR, and MMOI) hold their own settings and primitives and consolidate PL4 and PMU support flags into rapl_defaults (Kuppuswamy Sathyanarayanan) - Correct kernel-doc function parameter names in the power capping core code (Randy Dunlap) - Remove unneeded casting for HZ_PER_KHZ in devfreq (Andy Shevchenko) - Use _visible attribute to replace create/remove_sysfs_files() in devfreq (Pengjie Zhang) - Add Tegra114 support to activity monitor device in tegra30-devfreq as a preparation to upcoming EMC controller support (Svyatoslav Ryhel) - Fix mistakes in cpupower man pages, add the boost and epp options to the cpupower-frequency-info man page, and add the perf-bias option to the cpupower-info man page (Roberto Ricci) - Remove unnecessary extern declarations from getopt.h in arguments parsing functions in cpufreq-set, cpuidle-info, cpuidle-set, cpupower-info, and cpupower-set utilities (Kaushlendra Kumar)" * tag 'pm-7.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (74 commits) cpufreq/amd-pstate: Add POWER_SUPPLY select for dynamic EPP cpupower: remove extern declarations in cmd functions cpuidle: Simplify cpuidle_register_device() with guard() PM / devfreq: tegra30-devfreq: add support for Tegra114 PM / devfreq: use _visible attribute to replace create/remove_sysfs_files() PM / devfreq: Remove unneeded casting for HZ_PER_KHZ MAINTAINERS: amd-pstate: Step down as maintainer, add Prateek as reviewer cpufreq: Pass the policy to cpufreq_driver->adjust_perf() cpufreq/amd-pstate: Pass the policy to amd_pstate_update() cpufreq/amd-pstate-ut: Add a unit test for raw EPP cpufreq/amd-pstate: Add support for raw EPP writes cpufreq/amd-pstate: Add support for platform profile class cpufreq/amd-pstate: add kernel command line to override dynamic epp cpufreq/amd-pstate: Add dynamic energy performance preference Documentation: amd-pstate: fix dead links in the reference section cpufreq/amd-pstate: Cache the max frequency in cpudata Documentation/amd-pstate: Add documentation for amd_pstate_floor_{freq,count} Documentation/amd-pstate: List amd_pstate_prefcore_ranking sysfs file Documentation/amd-pstate: List amd_pstate_hw_prefcore sysfs file amd-pstate-ut: Add a testcase to validate the visibility of driver attributes ...
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/admin-guide/kernel-parameters.txt7
-rw-r--r--Documentation/admin-guide/pm/amd-pstate.rst87
-rw-r--r--Documentation/devicetree/bindings/arm/tegra/nvidia,tegra-ccplex-cluster.yaml1
-rw-r--r--Documentation/devicetree/bindings/cpufreq/cpufreq-qcom-hw.yaml1
4 files changed, 86 insertions, 10 deletions
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index c17ad454dd81..2075e7a9dcde 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -501,6 +501,13 @@ Kernel parameters
disable
Disable amd-pstate preferred core.
+ amd_dynamic_epp=
+ [X86]
+ disable
+ Disable amd-pstate dynamic EPP.
+ enable
+ Enable amd-pstate dynamic EPP.
+
amijoy.map= [HW,JOY] Amiga joystick support
Map of devices attached to JOY0DAT and JOY1DAT
Format: <a>,<b>
diff --git a/Documentation/admin-guide/pm/amd-pstate.rst b/Documentation/admin-guide/pm/amd-pstate.rst
index e1771f2225d5..f8e7050fc762 100644
--- a/Documentation/admin-guide/pm/amd-pstate.rst
+++ b/Documentation/admin-guide/pm/amd-pstate.rst
@@ -239,8 +239,12 @@ control its functionality at the system level. They are located in the
root@hr-test1:/home/ray# ls /sys/devices/system/cpu/cpufreq/policy0/*amd*
/sys/devices/system/cpu/cpufreq/policy0/amd_pstate_highest_perf
+ /sys/devices/system/cpu/cpufreq/policy0/amd_pstate_hw_prefcore
/sys/devices/system/cpu/cpufreq/policy0/amd_pstate_lowest_nonlinear_freq
/sys/devices/system/cpu/cpufreq/policy0/amd_pstate_max_freq
+ /sys/devices/system/cpu/cpufreq/policy0/amd_pstate_floor_freq
+ /sys/devices/system/cpu/cpufreq/policy0/amd_pstate_floor_count
+ /sys/devices/system/cpu/cpufreq/policy0/amd_pstate_prefcore_ranking
``amd_pstate_highest_perf / amd_pstate_max_freq``
@@ -264,14 +268,46 @@ This attribute is read-only.
``amd_pstate_hw_prefcore``
-Whether the platform supports the preferred core feature and it has been
-enabled. This attribute is read-only.
+Whether the platform supports the preferred core feature and it has
+been enabled. This attribute is read-only. This file is only visible
+on platforms which support the preferred core feature.
``amd_pstate_prefcore_ranking``
The performance ranking of the core. This number doesn't have any unit, but
larger numbers are preferred at the time of reading. This can change at
-runtime based on platform conditions. This attribute is read-only.
+runtime based on platform conditions. This attribute is read-only. This file
+is only visible on platforms which support the preferred core feature.
+
+``amd_pstate_floor_freq``
+
+The floor frequency associated with each CPU. Userspace can write any
+value between ``cpuinfo_min_freq`` and ``scaling_max_freq`` into this
+file. When the system is under power or thermal constraints, the
+platform firmware will attempt to throttle the CPU frequency to the
+value specified in ``amd_pstate_floor_freq`` before throttling it
+further. This allows userspace to specify different floor frequencies
+to different CPUs. For optimal results, threads of the same core
+should have the same floor frequency value. This file is only visible
+on platforms that support the CPPC Performance Priority feature.
+
+
+``amd_pstate_floor_count``
+
+The number of distinct Floor Performance levels supported by the
+platform. For example, if this value is 2, then the number of unique
+values obtained from the command ``cat
+/sys/devices/system/cpu/cpufreq/policy*/amd_pstate_floor_freq |
+sort -n | uniq`` should be at most this number for the behavior
+described in ``amd_pstate_floor_freq`` to take effect. A zero value
+implies that the platform supports unlimited floor performance levels.
+This file is only visible on platforms that support the CPPC
+Performance Priority feature.
+
+**Note**: When ``amd_pstate_floor_count`` is non-zero, the frequency to
+which the CPU is throttled under power or thermal constraints is
+undefined when the number of unique values of ``amd_pstate_floor_freq``
+across all CPUs in the system exceeds ``amd_pstate_floor_count``.
``energy_performance_available_preferences``
@@ -280,16 +316,22 @@ A list of all the supported EPP preferences that could be used for
These profiles represent different hints that are provided
to the low-level firmware about the user's desired energy vs efficiency
tradeoff. ``default`` represents the epp value is set by platform
-firmware. This attribute is read-only.
+firmware. ``custom`` designates that integer values 0-255 may be written
+as well. This attribute is read-only.
``energy_performance_preference``
The current energy performance preference can be read from this attribute.
and user can change current preference according to energy or performance needs
-Please get all support profiles list from
-``energy_performance_available_preferences`` attribute, all the profiles are
-integer values defined between 0 to 255 when EPP feature is enabled by platform
-firmware, if EPP feature is disabled, driver will ignore the written value
+Coarse named profiles are available in the attribute
+``energy_performance_available_preferences``.
+Users can also write individual integer values between 0 to 255.
+When dynamic EPP is enabled, writes to energy_performance_preference are blocked
+even when EPP feature is enabled by platform firmware. Lower epp values shift the bias
+towards improved performance while a higher epp value shifts the bias towards
+power-savings. The exact impact can change from one platform to the other.
+If a valid integer was last written, then a number will be returned on future reads.
+If a valid string was last written then a string will be returned on future reads.
This attribute is read-write.
``boost``
@@ -311,6 +353,24 @@ boost or `1` to enable it, for the respective CPU using the sysfs path
Other performance and frequency values can be read back from
``/sys/devices/system/cpu/cpuX/acpi_cppc/``, see :ref:`cppc_sysfs`.
+Dynamic energy performance profile
+==================================
+The amd-pstate driver supports dynamically selecting the energy performance
+profile based on whether the machine is running on AC or DC power.
+
+Whether this behavior is enabled by default depends on the kernel
+config option `CONFIG_X86_AMD_PSTATE_DYNAMIC_EPP`. This behavior can also be overridden
+at runtime by the sysfs file ``/sys/devices/system/cpu/cpufreq/policyX/dynamic_epp``.
+
+When set to enabled, the driver will select a different energy performance
+profile when the machine is running on battery or AC power. The driver will
+also register with the platform profile handler to receive notifications of
+user desired power state and react to those.
+When set to disabled, the driver will not change the energy performance profile
+based on the power source and will not react to user desired power state.
+
+Attempting to manually write to the ``energy_performance_preference`` sysfs
+file will fail when ``dynamic_epp`` is enabled.
``amd-pstate`` vs ``acpi-cpufreq``
======================================
@@ -422,6 +482,13 @@ For systems that support ``amd-pstate`` preferred core, the core rankings will
always be advertised by the platform. But OS can choose to ignore that via the
kernel parameter ``amd_prefcore=disable``.
+``amd_dynamic_epp``
+
+When AMD pstate is in auto mode, dynamic EPP will control whether the kernel
+autonomously changes the EPP mode. The default is configured by
+``CONFIG_X86_AMD_PSTATE_DYNAMIC_EPP`` but can be explicitly enabled with
+``amd_dynamic_epp=enable`` or disabled with ``amd_dynamic_epp=disable``.
+
User Space Interface in ``sysfs`` - General
===========================================
@@ -790,13 +857,13 @@ Reference
===========
.. [1] AMD64 Architecture Programmer's Manual Volume 2: System Programming,
- https://www.amd.com/system/files/TechDocs/24593.pdf
+ https://docs.amd.com/v/u/en-US/24593_3.44_APM_Vol2
.. [2] Advanced Configuration and Power Interface Specification,
https://uefi.org/sites/default/files/resources/ACPI_Spec_6_4_Jan22.pdf
.. [3] Processor Programming Reference (PPR) for AMD Family 19h Model 51h, Revision A1 Processors
- https://www.amd.com/system/files/TechDocs/56569-A1-PUB.zip
+ https://docs.amd.com/v/u/en-US/56569-A1-PUB_3.03
.. [4] Linux Kernel Selftests,
https://www.kernel.org/doc/html/latest/dev-tools/kselftest.html
diff --git a/Documentation/devicetree/bindings/arm/tegra/nvidia,tegra-ccplex-cluster.yaml b/Documentation/devicetree/bindings/arm/tegra/nvidia,tegra-ccplex-cluster.yaml
index 36dbd0838f2d..fe9c8791f227 100644
--- a/Documentation/devicetree/bindings/arm/tegra/nvidia,tegra-ccplex-cluster.yaml
+++ b/Documentation/devicetree/bindings/arm/tegra/nvidia,tegra-ccplex-cluster.yaml
@@ -24,6 +24,7 @@ properties:
enum:
- nvidia,tegra186-ccplex-cluster
- nvidia,tegra234-ccplex-cluster
+ - nvidia,tegra238-ccplex-cluster
reg:
maxItems: 1
diff --git a/Documentation/devicetree/bindings/cpufreq/cpufreq-qcom-hw.yaml b/Documentation/devicetree/bindings/cpufreq/cpufreq-qcom-hw.yaml
index 22eeaef14f55..98eb36bff172 100644
--- a/Documentation/devicetree/bindings/cpufreq/cpufreq-qcom-hw.yaml
+++ b/Documentation/devicetree/bindings/cpufreq/cpufreq-qcom-hw.yaml
@@ -35,6 +35,7 @@ properties:
- description: v2 of CPUFREQ HW (EPSS)
items:
- enum:
+ - qcom,eliza-cpufreq-epss
- qcom,milos-cpufreq-epss
- qcom,qcs8300-cpufreq-epss
- qcom,qdu1000-cpufreq-epss