diff options
| author | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2026-07-31 19:36:04 +0200 |
|---|---|---|
| committer | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2026-07-31 19:36:04 +0200 |
| commit | eb49643e66e0dd0b989e30a1c556e8c5d5398dc0 (patch) | |
| tree | 86d7e8dfebd3873b8cdc771692a6fe5400b6e5fa /Documentation/admin-guide/pm | |
| parent | 9e4cb21f2940230efc09f90c8335b5cbb3e26c41 (diff) | |
| parent | d06c75c22d5c95ee27e01fedcaa07231c9bd5c88 (diff) | |
Merge tag 'amd-pstate-v7.3-2026-07-30' of ssh://gitolite.kernel.org/pub/scm/linux/kernel/git/superm1/linux
Pull amd-pstate 7.3 content (07/30/26) from Mario Limonciello:
"* Changes for dynamic EPP
* Adjustments to the bios min perf feature
* Fixes to kernel doc"
* tag 'amd-pstate-v7.3-2026-07-30' of ssh://gitolite.kernel.org/pub/scm/linux/kernel/git/superm1/linux:
cpufreq/amd-pstate: Document missing kernel-doc members
cpufreq/amd-pstate-ut: Add unit test for CPPC Performance Priority
cpufreq/amd-pstate-ut: Add unit test for "dynamic" EPP mode
cpufreq/amd-pstate: Reduce the scope of exported symbols
Documentation/amd-pstate: Update dynamic_epp documentation with new behavior
cpufreq/amd-pstate: Remove "amd_dynamic_epp" cmdline and "dynamic_epp" sysfs
cpufreq/amd-pstate: Add dynamic EPP as an "energy_performance_preference" mode
cpufreq/amd-pstate: Extract platform profile to EPP conversion into a helper
cpufreq/amd-pstate: Remove the defensive check for bios_min_perf
cpufreq/amd-pstate: Set min_limit_freq based on bios_min_perf
Diffstat (limited to 'Documentation/admin-guide/pm')
| -rw-r--r-- | Documentation/admin-guide/pm/amd-pstate.rst | 45 |
1 files changed, 22 insertions, 23 deletions
diff --git a/Documentation/admin-guide/pm/amd-pstate.rst b/Documentation/admin-guide/pm/amd-pstate.rst index a95e2ebce005..c7bf7cc2db87 100644 --- a/Documentation/admin-guide/pm/amd-pstate.rst +++ b/Documentation/admin-guide/pm/amd-pstate.rst @@ -317,7 +317,9 @@ 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. ``custom`` designates that integer values 0-255 may be written -as well. This attribute is read-only. +as well. ``dynamic`` designates that the EPP is modified dynamically +on kernel events. See ``Dynamic energy performance profile`` section below to +know more about the ``dynamic`` mode. This attribute is read-only. ``energy_performance_preference`` @@ -326,13 +328,11 @@ and user can change current preference according to energy or performance needs 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. +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`` The `boost` sysfs attribute provides control over the CPU core @@ -356,21 +356,20 @@ Other performance and frequency values can be read back from 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 command line option -``amd_dynamic_epp`` is set. This behavior can also be overridden -at runtime by the sysfs file ``/sys/devices/system/cpu/amd_pstate/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. +profile based on the system profile and the current power source in active mode. + +The ``dynamic`` mode is listed in +``/sys/devices/system/cpu/cpuX/cpufreq/energy_performance_available_preferences`` +when available while running under the ``powersave`` governor. The ``dynamic`` +mode can be toggled on by writing the same to the sysfs file +``/sys/devices/system/cpu/cpuX/cpufreq/energy_performance_preference`` when +available. + +When ``energy_performance_preference`` is set to ``dynamic``, 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. ``amd-pstate`` vs ``acpi-cpufreq`` ====================================== |
