summaryrefslogtreecommitdiff
path: root/Documentation/admin-guide/pm
AgeCommit message (Collapse)Author
2021-06-29Merge tag 'pm-5.14-rc1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm Pull power management updates from Rafael Wysocki: "These add hybrid processors support to the intel_pstate driver and make it work with more processor models when HWP is disabled, make the intel_idle driver use special C6 idle state paremeters when package C-states are disabled, add cooling support to the tegra30 devfreq driver, rework the TEO (timer events oriented) cpuidle governor, extend the OPP (operating performance points) framework to use the required-opps DT property in more cases, fix some issues and clean up a number of assorted pieces of code. Specifics: - Make intel_pstate support hybrid processors using abstract performance units in the HWP interface (Rafael Wysocki). - Add Icelake servers and Cometlake support in no-HWP mode to intel_pstate (Giovanni Gherdovich). - Make cpufreq_online() error path be consistent with the CPU device removal path in cpufreq (Rafael Wysocki). - Clean up 3 cpufreq drivers and the statistics code (Hailong Liu, Randy Dunlap, Shaokun Zhang). - Make intel_idle use special idle state parameters for C6 when package C-states are disabled (Chen Yu). - Rework the TEO (timer events oriented) cpuidle governor to address some theoretical shortcomings in it (Rafael Wysocki). - Drop unneeded semicolon from the TEO governor (Wan Jiabing). - Modify the runtime PM framework to accept unassigned suspend and resume callback pointers (Ulf Hansson). - Improve pm_runtime_get_sync() documentation (Krzysztof Kozlowski). - Improve device performance states support in the generic power domains (genpd) framework (Ulf Hansson). - Fix some documentation issues in genpd (Yang Yingliang). - Make the operating performance points (OPP) framework use the required-opps DT property in use cases that are not related to genpd (Hsin-Yi Wang). - Make lazy_link_required_opp_table() use list_del_init instead of list_del/INIT_LIST_HEAD (Yang Yingliang). - Simplify wake IRQs handling in the core system-wide sleep support code and clean up some coding style inconsistencies in it (Tian Tao, Zhen Lei). - Add cooling support to the tegra30 devfreq driver and improve its DT bindings (Dmitry Osipenko). - Fix some assorted issues in the devfreq core and drivers (Chanwoo Choi, Dong Aisheng, YueHaibing)" * tag 'pm-5.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (39 commits) PM / devfreq: passive: Fix get_target_freq when not using required-opp cpufreq: Make cpufreq_online() call driver->offline() on errors opp: Allow required-opps to be used for non genpd use cases cpuidle: teo: remove unneeded semicolon in teo_select() dt-bindings: devfreq: tegra30-actmon: Add cooling-cells dt-bindings: devfreq: tegra30-actmon: Convert to schema PM / devfreq: userspace: Use DEVICE_ATTR_RW macro PM: runtime: Clarify documentation when callbacks are unassigned PM: runtime: Allow unassigned ->runtime_suspend|resume callbacks PM: runtime: Improve path in rpm_idle() when no callback PM: hibernate: remove leading spaces before tabs PM: sleep: remove trailing spaces and tabs PM: domains: Drop/restore performance state votes for devices at runtime PM PM: domains: Return early if perf state is already set for the device PM: domains: Split code in dev_pm_genpd_set_performance_state() cpuidle: teo: Use kerneldoc documentation in admin-guide cpuidle: teo: Rework most recent idle duration values treatment cpuidle: teo: Change the main idle state selection logic cpuidle: teo: Cosmetic modification of teo_select() cpuidle: teo: Cosmetic modifications of teo_update() ...
2021-06-29Merge branches 'pm-cpufreq' and 'pm-cpuidle'Rafael J. Wysocki
* pm-cpufreq: cpufreq: Make cpufreq_online() call driver->offline() on errors cpufreq: loongson2: Remove unused linux/sched.h headers cpufreq: sh: Remove unused linux/sched.h headers cpufreq: stats: Clean up local variable in cpufreq_stats_create_table() cpufreq: intel_pstate: hybrid: Fix build with CONFIG_ACPI unset cpufreq: sc520_freq: add 'fallthrough' to one case cpufreq: intel_pstate: Add Cometlake support in no-HWP mode cpufreq: intel_pstate: Add Icelake servers support in no-HWP mode cpufreq: intel_pstate: hybrid: CPU-specific scaling factor cpufreq: intel_pstate: hybrid: Avoid exposing two global attributes * pm-cpuidle: cpuidle: teo: remove unneeded semicolon in teo_select() cpuidle: teo: Use kerneldoc documentation in admin-guide cpuidle: teo: Rework most recent idle duration values treatment cpuidle: teo: Change the main idle state selection logic cpuidle: teo: Cosmetic modification of teo_select() cpuidle: teo: Cosmetic modifications of teo_update() intel_idle: Adjust the SKX C6 parameters if PC6 is disabled
2021-06-17docs: admin-guide: pm: avoid using ReST :doc:`foo` markupMauro Carvalho Chehab
The :doc:`foo` tag is auto-generated via automarkup.py. So, use the filename at the sources, instead of :doc:`foo`. Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org> Link: https://lore.kernel.org/r/04616d9fc0b4a0d33486fa0018631a2db2eba860.1623824363.git.mchehab+huawei@kernel.org Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2021-06-11cpuidle: teo: Use kerneldoc documentation in admin-guideRafael J. Wysocki
There are two descriptions of the TEO (Timer Events Oriented) cpuidle governor in the kernel source tree, one in the C file containing its code and one in cpuidle.rst which is part of admin-guide. Instead of trying to keep them both in sync and in order to reduce text duplication, include the governor description from the C file directly into cpuidle.rst. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2021-05-21cpufreq: intel_pstate: hybrid: Avoid exposing two global attributesRafael J. Wysocki
The turbo_pct and num_pstates sysfs attributes represent CPU properties that may be different for differenty types of CPUs in a hybrid processor, so avoid exposing them in that case. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2020-12-08Documentation: fix multiple typos found in the admin-guide subdirectoryAndrew Klychkov
Fix thirty five typos in dm-integrity.rst, dm-raid.rst, dm-zoned.rst, verity.rst, writecache.rst, tsx_async_abort.rst, md.rst, bttv.rst, dvb_references.rst, frontend-cardlist.rst, gspca-cardlist.rst, ipu3.rst, remote-controller.rst, mm/index.rst, numaperf.rst, userfaultfd.rst, module-signing.rst, imx-ddr.rst, intel-speed-select.rst, intel_pstate.rst, ramoops.rst, abi.rst, kernel.rst, vm.rst Signed-off-by: Andrew Klychkov <andrew.a.klychkov@gmail.com> Link: https://lore.kernel.org/r/20201204072848.GA49895@spblnx124.lan Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2020-11-02Documentation: PM: cpuidle: correct path nameJulia Lawall
cpu/ is needed before cpu<N>/ Signed-off-by: Julia Lawall <Julia.Lawall@inria.fr> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2020-11-02Documentation: PM: cpuidle: correct typoJulia Lawall
cerainly -> certainly Signed-off-by: Julia Lawall <Julia.Lawall@inria.fr> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2020-10-15docs: remove some replace macros like |struct foo|Mauro Carvalho Chehab
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 <mchehab+huawei@kernel.org>
2020-10-05Merge back cpuidle material for 5.10.Rafael J. Wysocki
* pm-cpuidle: cpuidle: record state entry rejection statistics cpuidle: psci: Allow PM domain to be initialized even if no OSI mode firmware: psci: Extend psci_set_osi_mode() to allow reset to PC mode ACPI: processor: Print more information when acpi_processor_evaluate_cst() fails cpuidle: tegra: Correctly handle result of arm_cpuidle_simple_enter()
2020-09-30Documentation: PM: Fix a reStructuredText syntax errorYoann Congal
Fix a reStructuredText syntax error in the cpuidle PM admin-guide documentation: the ``...'' quotation marks are parsed as partial ''...'' reStructuredText markup and break the output formatting. This change them to "...". Signed-off-by: Yoann Congal <yoann.congal@smile.fr> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2020-09-23cpuidle: record state entry rejection statisticsLina Iyer
CPUs may fail to enter the chosen idle state if there was a pending interrupt, causing the cpuidle driver to return an error value. Record that and export it via sysfs along with the other idle state statistics. This could prove useful in understanding behavior of the governor and the system during usecases that involve multiple CPUs. Signed-off-by: Lina Iyer <ilina@codeaurora.org> [ rjw: Changelog and documentation edits ] Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2020-09-01cpufreq: intel_pstate: Tweak the EPP sysfs interfaceRafael J. Wysocki
Modify the EPP sysfs interface to reject attempts to change the EPP to values different from 0 ("performance") in the active mode with the "performance" policy (ie. scaling_governor set to "performance"), to avoid situations in which the kernel appears to discard data passed to it via the EPP sysfs attribute. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Reviewed-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com> Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
2020-08-24Documentation: fix pm/intel_pstate build warning and wordingRandy Dunlap
Fix documentation build warning and sentence wording: Documentation/admin-guide/pm/intel_pstate.rst:568: WARNING: Unexpected indentation. Fixes: f473bf398bf1 ("cpufreq: intel_pstate: Allow raw energy performance preference value") Signed-off-by: Randy Dunlap <rdunlap@infradead.org> Cc: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com> Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2020-08-14Merge branch 'pm-cpufreq'Rafael J. Wysocki
* pm-cpufreq: cpufreq: intel_pstate: Implement passive mode with HWP enabled
2020-08-11cpufreq: intel_pstate: Implement passive mode with HWP enabledRafael J. Wysocki
Allow intel_pstate to work in the passive mode with HWP enabled and make it set the HWP minimum performance limit (HWP floor) to the P-state value given by the target frequency supplied by the cpufreq governor, so as to prevent the HWP algorithm and the CPU scheduler from working against each other, at least when the schedutil governor is in use, and update the intel_pstate documentation accordingly. Among other things, this allows utilization clamps to be taken into account, at least to a certain extent, when intel_pstate is in use and makes it more likely that sufficient capacity for deadline tasks will be provided. After this change, the resulting behavior of an HWP system with intel_pstate in the passive mode should be close to the behavior of the analogous non-HWP system with intel_pstate in the passive mode, except that the HWP algorithm is generally allowed to make the CPU run at a frequency above the floor P-state set by intel_pstate in the entire available range of P-states, while without HWP a CPU can run in a P-state above the requested one if the latter falls into the range of turbo P-states (referred to as the turbo range) or if the P-states of all CPUs in one package are coordinated with each other at the hardware level. [Note that in principle the HWP floor may not be taken into account by the processor if it falls into the turbo range, in which case the processor has a license to choose any P-state, either below or above the HWP floor, just like a non-HWP processor in the case when the target P-state falls into the turbo range.] With this change applied, intel_pstate in the passive mode assumes complete control over the HWP request MSR and concurrent changes of that MSR (eg. via the direct MSR access interface) are overridden by it. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com> Reviewed-by: Francisco Jerez <currojerez@riseup.net>
2020-08-04Merge tag 'docs-5.9' of git://git.lwn.net/linuxLinus Torvalds
Pull documentation updates from Jonathan Corbet: "It's been a busy cycle for documentation - hopefully the busiest for a while to come. Changes include: - Some new Chinese translations - Progress on the battle against double words words and non-HTTPS URLs - Some block-mq documentation - More RST conversions from Mauro. At this point, that task is essentially complete, so we shouldn't see this kind of churn again for a while. Unless we decide to switch to asciidoc or something...:) - Lots of typo fixes, warning fixes, and more" * tag 'docs-5.9' of git://git.lwn.net/linux: (195 commits) scripts/kernel-doc: optionally treat warnings as errors docs: ia64: correct typo mailmap: add entry for <alobakin@marvell.com> doc/zh_CN: add cpu-load Chinese version Documentation/admin-guide: tainted-kernels: fix spelling mistake MAINTAINERS: adjust kprobes.rst entry to new location devices.txt: document rfkill allocation PCI: correct flag name docs: filesystems: vfs: correct flag name docs: filesystems: vfs: correct sync_mode flag names docs: path-lookup: markup fixes for emphasis docs: path-lookup: more markup fixes docs: path-lookup: fix HTML entity mojibake CREDITS: Replace HTTP links with HTTPS ones docs: process: Add an example for creating a fixes tag doc/zh_CN: add Chinese translation prefer section doc/zh_CN: add clearing-warn-once Chinese version doc/zh_CN: add admin-guide index doc:it_IT: process: coding-style.rst: Correct __maybe_unused compiler label futex: MAINTAINERS: Re-add selftests directory ...
2020-07-05Documentation/admin-guide: intel-speed-select: drop doubled wordsRandy Dunlap
Drop the doubled words "that" and "and". Signed-off-by: Randy Dunlap <rdunlap@infradead.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: linux-doc@vger.kernel.org Cc: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com> Cc: platform-driver-x86@vger.kernel.org Link: https://lore.kernel.org/r/20200704032020.21923-11-rdunlap@infradead.org Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2020-07-05Documentation/admin-guide: intel_pstate: drop doubled wordRandy Dunlap
Drop the doubled word "to". Signed-off-by: Randy Dunlap <rdunlap@infradead.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: linux-doc@vger.kernel.org Cc: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com> Cc: Len Brown <lenb@kernel.org> Cc: linux-pm@vger.kernel.org Link: https://lore.kernel.org/r/20200704032020.21923-10-rdunlap@infradead.org Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2020-07-02cpufreq: Specify default governor on command lineQuentin Perret
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 <qperret@google.com> [ 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 <viresh.kumar@linaro.org> [ rjw: Changelog ] Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2020-07-02cpufreq: intel_pstate: Allow raw energy performance preference valueSrinivas Pandruvada
Currently using attribute "energy_performance_preference", user space can write one of the four per-defined preference string. These preference strings gets mapped to a hard-coded Energy-Performance Preference (EPP) or Energy-Performance Bias (EPB) knob. These four values are supposed to cover broad spectrum of use cases, but are not uniformly distributed in the range. There are number of cases, where this is not enough. For example: Suppose user wants more performance when connected to AC. Instead of using default "balance performance", the "performance" setting can be used. This changes EPP value from 0x80 to 0x00. But setting EPP to 0, results in electrical and thermal issues on some platforms. This results in aggressive throttling, which causes a drop in performance. But some value between 0x80 and 0x00 results in better performance. But that value can't be fixed as the power curve is not linear. In some cases just changing EPP from 0x80 to 0x75 is enough to get significant performance gain. Similarly on battery the default "balance_performance" mode can be aggressive in power consumption. But picking up the next choice "balance power" results in too much loss of performance, which results in bad user experience in use cases like "Google Hangout". It was observed that some value between these two EPP is optimal. This change allows fine grain EPP tuning for platform like Chromebook or for users who wants to fine tune power and performance. Here based on the product and use cases, different EPP values can be set. This change is similar to the change done for: /sys/devices/system/cpu/cpu*/power/energy_perf_bias where user has choice to write a predefined string or raw value. The change itself is trivial. When user preference doesn't match predefined string preferences and value is an unsigned integer and in range, use that value for EPP. When the EPP feature is not present writing raw value is not supported. Suggested-by: Len Brown <lenb@kernel.org> Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2020-07-02cpufreq: intel_pstate: Allow enable/disable energy efficiencySrinivas Pandruvada
By default intel_pstate the driver disables energy efficiency by setting MSR_IA32_POWER_CTL bit 19 for Kaby Lake desktop CPU model in HWP mode. This CPU model is also shared by Coffee Lake desktop CPUs. This allows these systems to reach maximum possible frequency. But this adds power penalty, which some customers don't want. They want some way to enable/ disable dynamically. So, add an additional attribute "energy_efficiency" under /sys/devices/system/cpu/intel_pstate/ for these CPU models. This allows to read and write bit 19 ("Disable Energy Efficiency Optimization") in the MSR IA32_POWER_CTL. This attribute is present in both HWP and non-HWP mode as this has an effect in both modes. Refer to Intel Software Developer's manual for details. The scope of this bit is package wide. Also these systems are single package systems. So read/write MSR on the current CPU is enough. The energy efficiency (EE) bit setting needs to be preserved during suspend/resume and CPU offline/online operation. To do this: - Restoring the EE setting from the cpufreq resume() callback, if there is change from the system default. - By default, don't disable EE from cpufreq init() callback for matching CPU models. Since the scope is package wide and is a single package system, move the disable EE calls from init() callback to intel_pstate_init() function, which is called only once. Suggested-by: Len Brown <lenb@kernel.org> Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2020-06-01Merge branches 'pm-devfreq', 'powercap', 'pm-docs' and 'pm-tools'Rafael J. Wysocki
* pm-devfreq: PM / devfreq: Use lockdep asserts instead of manual checks for locked mutex PM / devfreq: imx-bus: Fix inconsistent IS_ERR and PTR_ERR PM / devfreq: Replace strncpy with strscpy PM / devfreq: imx: Register interconnect device PM / devfreq: Add generic imx bus scaling driver PM / devfreq: tegra30: Delete an error message in tegra_devfreq_probe() PM / devfreq: tegra30: Make CPUFreq notifier to take into account boosting * powercap: powercap: RAPL: remove unused local MSR define powercap/intel_rapl: add support for ElkhartLake * pm-docs: Documentation: admin-guide: pm: Document intel-speed-select * pm-tools: cpupower: Remove unneeded semicolon
2020-06-01Merge branch 'pm-cpufreq'Rafael J. Wysocki
* pm-cpufreq: cpufreq: Fix up cpufreq_boost_set_sw() cpufreq: fix minor typo in struct cpufreq_driver doc comment cpufreq: qoriq: Add platform dependencies clk: qoriq: add cpufreq platform device cpufreq: qoriq: convert to a platform driver cpufreq: qcom: fix wrong compatible binding cpufreq: imx-cpufreq-dt: support i.MX7ULP cpufreq: dt: Add support for r8a7742 cpufreq: Add i.MX7ULP to cpufreq-dt-platdev blacklist cpufreq: omap: Build driver by default for ARCH_OMAP2PLUS cpufreq: intel_pstate: Use passive mode by default without HWP
2020-05-19Documentation: admin-guide: pm: Document intel-speed-selectSrinivas Pandruvada
Added documentation to configure servers to use Intel(R) Speed Select Technology using intel-speed-select tool. Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com> Acked-by: Andriy Shevchenko <andy.shevchenko@gmail.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2020-05-19Documentation: cpuidle: update the documentHanjun Guo
Update the document after the remove of cpuidle_sysfs_switch. Signed-off-by: Hanjun Guo <guohanjun@huawei.com> Reviewed-by: Doug Smythies <dsmythies@telus.net> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2020-04-17cpufreq: intel_pstate: Use passive mode by default without HWPRafael J. Wysocki
After recent changes allowing scale-invariant utilization to be used on x86, the schedutil governor on top of intel_pstate in the passive mode should be on par with (or better than) the active mode "powersave" algorithm of intel_pstate on systems in which hardware-managed P-states (HWP) are not used, so it should not be necessary to use the internal scaling algorithm in those cases. Accordingly, modify intel_pstate to start in the passive mode by default if the processor at hand does not support HWP of if the driver is requested to avoid using HWP through the kernel command line. Among other things, that will allow utilization clamps and the support for RT/DL tasks in the schedutil governor to be utilized on systems in which intel_pstate is used. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2020-04-03Documentation: PM: sleep: Document system-wide suspend code flowsRafael J. Wysocki
Add a document describing high-level system-wide suspend code flows in Linux. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2020-03-30Merge branches 'pm-devfreq', 'powercap' and 'pm-docs'Rafael J. Wysocki
* pm-devfreq: PM / devfreq: Get rid of some doc warnings PM / devfreq: Fix handling dev_pm_qos_remove_request result PM / devfreq: Fix a typo in a comment PM / devfreq: Change to DEVFREQ_GOV_UPDATE_INTERVAL event name PM / devfreq: Remove unneeded extern keyword PM / devfreq: Use constant name of userspace governor * powercap: powercap: idle_inject: Replace zero-length array with flexible-array member * pm-docs: docs: cpu-freq: convert cpufreq-stats.txt to ReST docs: cpu-freq: convert cpu-drivers.txt to ReST docs: cpu-freq: convert core.txt to ReST docs: cpu-freq: convert index.txt to ReST docs: cpufreq: fix a broken reference Documentation: cpufreq: Move legacy driver documentation
2020-03-30Merge branch 'pm-cpufreq'Rafael J. Wysocki
* pm-cpufreq: cpufreq: intel_pstate: Simplify intel_pstate_cpu_init() cpufreq: qcom: Add support for krait based socs cpufreq: imx6q-cpufreq: Improve the logic of -EPROBE_DEFER handling cpufreq: Use scnprintf() for avoiding potential buffer overflow Documentation: intel_pstate: update links for references cpufreq: intel_pstate: Consolidate policy verification cpufreq: dt: Allow platform specific intermediate callbacks cpufreq: imx-cpufreq-dt: Correct i.MX8MP's market segment fuse location cpufreq: imx6q: read OCOTP through nvmem for imx6q cpufreq: imx6q: fix error handling cpufreq: imx-cpufreq-dt: Add "cpu-supply" property check cpufreq: ti-cpufreq: Add support for OPP_PLUS cpufreq: imx6q: Fixes unwanted cpu overclocking on i.MX6ULL
2020-03-14Documentation: intel_pstate: update links for referencesAlex Hung
URLs for presentation and Intel Software Developer’s Manual are updated as they were using "http" which are gradually replaced by "https". Signed-off-by: Alex Hung <alex.hung@canonical.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2020-03-02Documentation: cpufreq: Move legacy driver documentationRafael J. Wysocki
There are three legacy driver documents in Documentation/cpu-freq/ that were added years ago and converting them each to the .rst format is rather pointless, even though there is some value in preserving them. However, if they are preserved, they need to go into the admin-guide part of cpufreq documentation where they belong (at least to a certain extent). To preserve them with minimum amount of changes and put them into the right place, and make it possible to process them into HTML (and other formats) along with the rest of the documentation, move them each as a "literal text" block into a separate section of a single .rst "wrapper" file under Documentation/admin-guide/pm/. While at it, repair the PCC specification URL in one of them. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2020-02-14Documentation: PM: QoS: Update to reflect previous code changesRafael J. Wysocki
Update the PM QoS documentation to reflect the previous code changes regarding the removal of PM QoS classes and the CPU latency QoS API rework. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org> Reviewed-by: Amit Kucheria <amit.kucheria@linaro.org> Tested-by: Amit Kucheria <amit.kucheria@linaro.org>
2020-02-07Merge branches 'pm-avs' and 'pm-cpuidle'Rafael J. Wysocki
* pm-avs: power: avs: qcom-cpr: Avoid clang -Wsometimes-uninitialized in cpr_scale power: avs: qcom-cpr: add unspecified HAS_IOMEM dependency PM / AVS: rockchip-io: fix the supply naming for the emmc supply on px30 power: avs: qcom-cpr: add a printout after the driver has been initialized * pm-cpuidle: cpuidle: Documentation: Clean up PM QoS description intel_idle: Introduce 'states_off' module parameter intel_idle: Introduce 'use_acpi' module parameter
2020-02-05cpuidle: Documentation: Clean up PM QoS descriptionRafael J. Wysocki
Clean up the language in one paragraph in the PM QoS description in Documentation/admin-guide/pm/cpuidle.rst. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2020-02-03Documentation: admin-guide: PM: Update sleep states documentationRafael J. Wysocki
There is some information in Documentation/power/interface.rst that is still missing from Documentation/admin-guide/pm/sleep-states.rst and really should be present in there, so update the latter by adding that information to it and delete the former (as it becomes redundant after that and it is somewhat outdated). While at it, clean up some assorted pieces of sleep-states.rst a bit. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2020-02-03intel_idle: Introduce 'states_off' module parameterRafael J. Wysocki
In certain system configurations it may not be desirable to use some C-states assumed to be available by intel_idle and the driver needs to be prevented from using them even before the cpuidle sysfs interface becomes accessible to user space. Currently, the only way to achieve that is by setting the 'max_cstate' module parameter to a value lower than the index of the shallowest of the C-states in question, but that may be overly intrusive, because it effectively makes all of the idle states deeper than the 'max_cstate' one go away (and the C-state to avoid may be in the middle of the range normally regarded as available). To allow that limitation to be overcome, introduce a new module parameter called 'states_off' to represent a list of idle states to be disabled by default in the form of a bitmask and update the documentation to cover it. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2020-02-03intel_idle: Introduce 'use_acpi' module parameterRafael J. Wysocki
For diagnostics, it is generally useful to be able to make intel_idle take the system's ACPI tables into consideration even if that is not required for the processor model in there, so introduce a new module parameter, 'use_acpi', to make that happen and update the documentation to cover it. While at it, fix the 'no_acpi' module parameter name in the documentation. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2020-01-15Documentation: admin-guide: PM: Add intel_idle documentRafael J. Wysocki
Add an admin-guide document for the intel_idle driver to describe how it works: how it enumerates idle states, what happens during the initialization of it, how it can be controlled via the kernel command line and so on. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
2019-12-27cpuidle: Allow idle states to be disabled by defaultRafael J. Wysocki
In certain situations it may be useful to prevent some idle states from being used by default while allowing user space to enable them later on. For this purpose, introduce a new state flag, CPUIDLE_FLAG_OFF, to mark idle states that should be disabled by default, make the core set CPUIDLE_STATE_DISABLED_BY_USER for those states at the initialization time and add a new state attribute in sysfs, "default_status", to inform user space of the initial status of the given idle state ("disabled" if CPUIDLE_FLAG_OFF is set for it, "enabled" otherwise). Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2019-05-06Merge branches 'pm-docs' and 'pm-misc'Rafael J. Wysocki
* pm-docs: Documentation: PM: Unify copyright notices Documentation: PM: Add SPDX license tags to multiple files cpufreq: intel_pstate: Documentation: Add references sections * pm-misc: firmware/psci: add support for SYSTEM_RESET2 drivers: firmware: psci: Announce support for OS initiated suspend mode drivers: firmware: psci: Simplify error path of psci_dt_init() drivers: firmware: psci: Split psci_dt_cpu_init_idle() MAINTAINERS: Update files for PSCI drivers: firmware: psci: Move psci to separate directory
2019-04-08admin-guide: pm: intel_epb: Add SPDX license tag and copyright noticeRafael J. Wysocki
Add an SPDX license tag and a copyright notice to the intel_epb.rst file under Documentation/admin-quide/pm. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
2019-04-08Documentation: PM: Unify copyright noticesRafael J. Wysocki
Unify copyright notices in the .rst files under Documentation/driver-api/pm and Documentation/admin-quide/pm. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
2019-04-08Documentation: PM: Add SPDX license tags to multiple filesRafael J. Wysocki
Add SPDX license tags to .rst files under Documentation/driver-api/pm and Documentation/admin-quide/pm. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
2019-04-08cpufreq: intel_pstate: Documentation: Add references sectionsRafael J. Wysocki
Add separate refereces sections to the cpufreq.rst and intel_pstate.rst documents under admin-quide/pm and list the references to external documentation in there. Update the ACPI specification URL while at it. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
2019-04-07PM / arch: x86: MSR_IA32_ENERGY_PERF_BIAS sysfs interfaceRafael J. Wysocki
The Performance and Energy Bias Hint (EPB) is expected to be set by user space through the generic MSR interface, but that interface is not particularly nice and there are security concerns regarding it, so it is not always available. For this reason, add a sysfs interface for reading and updating the EPB, in the form of a new attribute, energy_perf_bias, located under /sys/devices/system/cpu/cpu#/power/ for online CPUs that support the EPB feature. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Reviewed-by: Hannes Reinecke <hare@suse.com> Acked-by: Borislav Petkov <bp@suse.de>
2019-04-07PM / arch: x86: Rework the MSR_IA32_ENERGY_PERF_BIAS handlingRafael J. Wysocki
The current handling of MSR_IA32_ENERGY_PERF_BIAS in the kernel is problematic, because it may cause changes made by user space to that MSR (with the help of the x86_energy_perf_policy tool, for example) to be lost every time a CPU goes offline and then back online as well as during system-wide power management transitions into sleep states and back into the working state. The first problem is that if the current EPB value for a CPU going online is 0 ('performance'), the kernel will change it to 6 ('normal') regardless of whether or not this is the first bring-up of that CPU. That also happens during system-wide resume from sleep states (including, but not limited to, hibernation). However, the EPB may have been adjusted by user space this way and the kernel should not blindly override that setting. The second problem is that if the platform firmware resets the EPB values for any CPUs during system-wide resume from a sleep state, the kernel will not restore their previous EPB values that may have been set by user space before the preceding system-wide suspend transition. Again, that behavior may at least be confusing from the user space perspective. In order to address these issues, rework the handling of MSR_IA32_ENERGY_PERF_BIAS so that the EPB value is saved on CPU offline and restored on CPU online as well as (for the boot CPU) during the syscore stages of system-wide suspend and resume transitions, respectively. However, retain the policy by which the EPB is set to 6 ('normal') on the first bring-up of each CPU if its initial value is 0, based on the observation that 0 may mean 'not initialized' just as well as 'performance' in that case. While at it, move the MSR_IA32_ENERGY_PERF_BIAS handling code into a separate file and document it in Documentation/admin-guide. Fixes: abe48b108247 (x86, intel, power: Initialize MSR_IA32_ENERGY_PERF_BIAS) Fixes: b51ef52df71c (x86/cpu: Restore MSR_IA32_ENERGY_PERF_BIAS after resume) Reported-by: Thomas Renninger <trenn@suse.de> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Reviewed-by: Hannes Reinecke <hare@suse.com> Acked-by: Borislav Petkov <bp@suse.de> Acked-by: Thomas Gleixner <tglx@linutronix.de>
2019-01-16cpuidle: New timer events oriented governor for tickless systemsRafael J. Wysocki
The venerable menu governor does some things that are quite questionable in my view. First, it includes timer wakeups in the pattern detection data and mixes them up with wakeups from other sources which in some cases causes it to expect what essentially would be a timer wakeup in a time frame in which no timer wakeups are possible (because it knows the time until the next timer event and that is later than the expected wakeup time). Second, it uses the extra exit latency limit based on the predicted idle duration and depending on the number of tasks waiting on I/O, even though those tasks may run on a different CPU when they are woken up. Moreover, the time ranges used by it for the sleep length correction factors depend on whether or not there are tasks waiting on I/O, which again doesn't imply anything in particular, and they are not correlated to the list of available idle states in any way whatever. Also, the pattern detection code in menu may end up considering values that are too large to matter at all, in which cases running it is a waste of time. A major rework of the menu governor would be required to address these issues and the performance of at least some workloads (tuned specifically to the current behavior of the menu governor) is likely to suffer from that. It is thus better to introduce an entirely new governor without them and let everybody use the governor that works better with their actual workloads. The new governor introduced here, the timer events oriented (TEO) governor, uses the same basic strategy as menu: it always tries to find the deepest idle state that can be used in the given conditions. However, it applies a different approach to that problem. First, it doesn't use "correction factors" for the time till the closest timer, but instead it tries to correlate the measured idle duration values with the available idle states and use that information to pick up the idle state that is most likely to "match" the upcoming CPU idle interval. Second, it doesn't take the number of "I/O waiters" into account at all and the pattern detection code in it avoids taking timer wakeups into account. It also only uses idle duration values less than the current time till the closest timer (with the tick excluded) for that purpose. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
2018-12-21Merge branches 'pm-cpuidle', 'pm-cpufreq' and 'pm-cpufreq-sched'Rafael J. Wysocki
* pm-cpuidle: cpuidle: Add 'above' and 'below' idle state metrics cpuidle: big.LITTLE: fix refcount leak cpuidle: Add cpuidle.governor= command line parameter cpuidle: poll_state: Disregard disable idle states Documentation: admin-guide: PM: Add cpuidle document * pm-cpufreq: cpufreq: qcom-hw: Add support for QCOM cpufreq HW driver dt-bindings: cpufreq: Introduce QCOM cpufreq firmware bindings cpufreq: nforce2: Remove meaningless return cpufreq: ia64: Remove unused header files cpufreq: imx6q: save one condition block for normal case of nvmem read cpufreq: imx6q: remove unused code cpufreq: pmac64: add of_node_put() cpufreq: powernv: add of_node_put() Documentation: intel_pstate: Clarify coordination of P-State limits cpufreq: intel_pstate: Force HWP min perf before offline cpufreq: s3c24xx: Change to use DEFINE_SHOW_ATTRIBUTE macro * pm-cpufreq-sched: sched/cpufreq: Add the SPDX tags
2018-12-12cpuidle: Add 'above' and 'below' idle state metricsRafael J. Wysocki
Add two new metrics for CPU idle states, "above" and "below", to count the number of times the given state had been asked for (or entered from the kernel's perspective), but the observed idle duration turned out to be too short or too long for it (respectively). These metrics help to estimate the quality of the CPU idle governor in use. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>