kernel/Documentation/admin-guide/pm/cpufreq.rst, branch linux-rolling-stable

cpufreq: Drop unused symbol CPUFREQ_ETERNAL

2025-10-01T11:57:22Z

Drop CPUFREQ_ETERNAL that has no users any more along with all references to it in the documentation. No functional impact. Reviewed-by: Mario Limonciello (AMD) Reviewed-by: Jie Zhan Signed-off-by: Rafael J. Wysocki Acked-by: Viresh Kumar Reviewed-by: Qais Yousef

cpufreq: docs: userspace: Explain HW coordination influence

2025-06-18T19:33:01Z

Extend the "scaling_setspeed" sysfs attribute description in the userspace governor documentation to cover possible differences between the requested and actual CPU frequency. Signed-off-by: Shashank Balaji Link: https://patch.msgid.link/20250527-userspace-governor-doc-v2-2-0e22c69920f2@sony.com [ rjw: Subject and changelog edits ] Signed-off-by: Rafael J. Wysocki

cpufreq: editing corrections to cpufreq.rst

2025-04-14T16:29:32Z

Change a few words and abbreviations/punctuation. Change one echo command to include a trailing '`'. Signed-off-by: Randy Dunlap Cc: Rafael J. Wysocki Cc: Viresh Kumar Cc: linux-pm@vger.kernel.org Cc: Jonathan Corbet Signed-off-by: Jonathan Corbet Link: https://lore.kernel.org/r/20250405001447.4039463-1-rdunlap@infradead.org

cpufreq: Introduce an optional cpuinfo_avg_freq sysfs entry

2025-02-17T18:09:31Z

Currently the CPUFreq core exposes two sysfs attributes that can be used to query current frequency of a given CPU(s): namely cpuinfo_cur_freq and scaling_cur_freq. Both provide slightly different view on the subject and they do come with their own drawbacks. cpuinfo_cur_freq provides higher precision though at a cost of being rather expensive. Moreover, the information retrieved via this attribute is somewhat short lived as frequency can change at any point of time making it difficult to reason from. scaling_cur_freq, on the other hand, tends to be less accurate but then the actual level of precision (and source of information) varies between architectures making it a bit ambiguous. The new attribute, cpuinfo_avg_freq, is intended to provide more stable, distinct interface, exposing an average frequency of a given CPU(s), as reported by the hardware, over a time frame spanning no more than a few milliseconds. As it requires appropriate hardware support, this interface is optional. Note that under the hood, the new attribute relies on the information provided by arch_freq_get_on_cpu, which, up to this point, has been feeding data for scaling_cur_freq attribute, being the source of ambiguity when it comes to interpretation. This has been amended by restoring the intended behavior for scaling_cur_freq, with a new dedicated config option to maintain status quo for those, who may need it. CC: Jonathan Corbet CC: Thomas Gleixner CC: Ingo Molnar CC: Borislav Petkov CC: Dave Hansen CC: H. Peter Anvin CC: Phil Auld CC: x86@kernel.org CC: linux-doc@vger.kernel.org Signed-off-by: Beata Michalska Reviewed-by: Prasanna Kumar T S M Reviewed-by: Sumit Gupta Acked-by: Viresh Kumar Acked-by: Rafael J. Wysocki Link: https://lore.kernel.org/r/20250131162439.3843071-3-beata.michalska@arm.com Signed-off-by: Catalin Marinas

cpufreq: docs: Reflect latency changes in docs

2024-10-21T11:20:03Z

There were two changes related to transition latency recently. Namely commit e13aa799c2a6 ("cpufreq: Change default transition delay to 2ms") and commit 37c6dccd6837 ("cpufreq: Remove LATENCY_MULTIPLIER"). Both changed the defaults / maximums so let the documentation reflect that. Signed-off-by: Christian Loehle Link: https://patch.msgid.link/46853b6e-bad5-4ace-9b23-ff157f234ae3@arm.com Signed-off-by: Rafael J. Wysocki

cpufreq: docs: Add missing scaling_available_frequencies description

2024-07-02T18:51:08Z

Add a description of the scaling_available_frequencies attribute in sysfs to the documentation. Signed-off-by: Raphael Gallais-Pou Reviewed-by: Bagas Sanjaya Acked-by: Viresh Kumar Link: https://patch.msgid.link/20240701171040.369030-1-rgallaispou@gmail.com Signed-off-by: Rafael J. Wysocki

docs: remove some replace macros like |struct foo|

2020-10-15T05:49:40Z

There are three files with replace macros for structs, mapping them into Sphinx 2.x C domain references. Well, this is broken on Sphinx 3.x. Also, for Sphinx 2.x, the automarkup macro should be able to take care of them. So, let's just drop those. Signed-off-by: Mauro Carvalho Chehab

cpufreq: Specify default governor on command line

2020-07-02T11:03:30Z

Currently, the only way to specify the default CPUfreq governor is via Kconfig options, which suits users who can build the kernel themselves perfectly. However, for those who use a distro-like kernel (such as Android, with the Generic Kernel Image project), the only way to use a non-default governor is to boot to userspace, and to then switch using the sysfs interface. Being able to specify the default governor on the command line, like is the case for cpuidle, would allow those users to specify their governor of choice earlier on, and to simplify the userspace boot procedure slighlty. To support this use-case, add a kernel command line parameter allowing the default governor for CPUfreq to be specified, which takes precedence over the built-in default. This implementation has one notable limitation: the default governor must be registered before the driver. This is solved for builtin governors and drivers using appropriate *_initcall() functions. And in the modular case, this must be reflected as a constraint on the module loading order. Signed-off-by: Quentin Perret [ Viresh: Converted 'default_governor' to a string and parsing it only at initcall level, and several updates to cpufreq_init_policy(). ] Signed-off-by: Viresh Kumar [ rjw: Changelog ] Signed-off-by: Rafael J. Wysocki

Documentation: PM: Unify copyright notices

2019-04-08T10:57:47Z

Unify copyright notices in the .rst files under Documentation/driver-api/pm and Documentation/admin-quide/pm. Signed-off-by: Rafael J. Wysocki Acked-by: Viresh Kumar

Documentation: PM: Add SPDX license tags to multiple files

2019-04-08T10:57:47Z

Add SPDX license tags to .rst files under Documentation/driver-api/pm and Documentation/admin-quide/pm. Signed-off-by: Rafael J. Wysocki Acked-by: Viresh Kumar