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2022-07-28sysfs docs: ABI: Fix typo in commentSlark Xiao
Fix typo in the comment Signed-off-by: Slark Xiao <slark_xiao@163.com> Link: https://lore.kernel.org/r/20220721020623.20974-1-slark_xiao@163.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-09-28ABI: sysfs-devices-power: add some debug sysfs filesMauro Carvalho Chehab
Those files were added back in Apr 2010, but there's no documentation for them yet. Fixes: c92445fadb91 ("PM / Runtime: Add sysfs debug files") Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org> Link: https://lore.kernel.org/r/df6c3ae0ffc2dddf73d7a5baf696a4aa260fb576.1632750608.git.mchehab+huawei@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-09-28ABI: sysfs-devices-power: document some RPM statisticsMauro Carvalho Chehab
Changeset 8d4b9d1bfef1 ("PM / Runtime: Add runtime PM statistics (v3)") added runtime_active_time and runtime_suspended_time, in order to allow powertop to identify the amount of time a device is active/suspended. Add an ABI description for those. Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org> Link: https://lore.kernel.org/r/d5524b966d081c650121c4c496c2f7ab3df524e9.1632750608.git.mchehab+huawei@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-09-06PM: runtime: Documentation: add runtime_status ABI documentAkinobu Mita
/sys/devices/.../power/runtime_status is introduced by commit c92445fadb91 ("PM / Runtime: Add sysfs debug files"). Then commit 0fcb4eef8294 ("PM / Runtime: Make runtime_status attribute not debug-only (v. 2)") made the runtime_status attribute available without CONFIG_PM_ADVANCED_DEBUG. This adds missing runtime_status ABI document. Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2017-11-08PM / QoS: Fix device resume latency frameworkRafael J. Wysocki
The special value of 0 for device resume latency PM QoS means "no restriction", but there are two problems with that. First, device resume latency PM QoS requests with 0 as the value are always put in front of requests with positive values in the priority lists used internally by the PM QoS framework, causing 0 to be chosen as an effective constraint value. However, that 0 is then interpreted as "no restriction" effectively overriding the other requests with specific restrictions which is incorrect. Second, the users of device resume latency PM QoS have no way to specify that *any* resume latency at all should be avoided, which is an artificial limitation in general. To address these issues, modify device resume latency PM QoS to use S32_MAX as the "no constraint" value and 0 as the "no latency at all" one and rework its users (the cpuidle menu governor, the genpd QoS governor and the runtime PM framework) to follow these changes. Also add a special "n/a" value to the corresponding user space I/F to allow user space to indicate that it cannot accept any resume latencies at all for the given device. Fixes: 85dc0b8a4019 (PM / QoS: Make it possible to expose PM QoS latency constraints) Link: https://bugzilla.kernel.org/show_bug.cgi?id=197323 Reported-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Tested-by: Reinette Chatre <reinette.chatre@intel.com> Tested-by: Geert Uytterhoeven <geert+renesas@glider.be> Tested-by: Tero Kristo <t-kristo@ti.com> Reviewed-by: Ramesh Thomas <ramesh.thomas@intel.com>
2017-10-14PM / QoS: Drop PM_QOS_FLAG_REMOTE_WAKEUPRafael J. Wysocki
The PM QoS flag PM_QOS_FLAG_REMOTE_WAKEUP is not used consistently and the vast majority of code simply assumes that remote wakeup should be enabled for devices in runtime suspend if they can generate wakeup signals, so drop it. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Ulf Hansson <ulf.hansson@linaro.org> Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
2014-04-07PM / wakeup: Correct presence vs. emptiness of wakeup_* attributesGeert Uytterhoeven
According to the documentation, the various wakeup_* attributes in sysfs are not present if the device is not enabled to wake up the system. This is not correct: the attributes are not present if the device is not capable to wake up the system. They are empty if the device is not enabled to wake up the system. Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2014-02-11PM / QoS: Introcuce latency tolerance device PM QoS typeRafael J. Wysocki
Add a new latency tolerance device PM QoS type to be use for specifying active state (RPM_ACTIVE) memory access (DMA) latency tolerance requirements for devices. It may be used to prevent hardware from choosing overly aggressive energy-saving operation modes (causing too much latency to appear) for the whole platform. This feature reqiures hardware support, so it only will be available for devices having a new .set_latency_tolerance() callback in struct dev_pm_info populated, in which case the routine pointed to by it should implement whatever is necessary to transfer the effective requirement value to the hardware. Whenever the effective latency tolerance changes for the device, its .set_latency_tolerance() callback will be executed and the effective value will be passed to it. If that value is negative, which means that the list of latency tolerance requirements for the device is empty, the callback is expected to switch the underlying hardware latency tolerance control mechanism to an autonomous mode if available. If that value is PM_QOS_LATENCY_ANY, in turn, and the hardware supports a special "no requirement" setting, the callback is expected to use it. That allows software to prevent the hardware from automatically updating the device's latency tolerance in response to its power state changes (e.g. during transitions from D3cold to D0), which generally may be done in the autonomous latency tolerance control mode. If .set_latency_tolerance() is present for the device, a new pm_qos_latency_tolerance_us attribute will be present in the devivce's power directory in sysfs. Then, user space can use that attribute to specify its latency tolerance requirement for the device, if any. Writing "any" to it means "no requirement, but do not let the hardware control latency tolerance" and writing "auto" to it allows the hardware to be switched to the autonomous mode if there are no other requirements from the kernel side in the device's list. This changeset includes a fix from Mika Westerberg. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-10-09MAINTAINERS / Documentation: Update Rafael's e-mail addressRafael J. Wysocki
The e-mail address rjw@sisk.pl that I have been using for quite some time is going to expire at one point, so replace it with a new one, rjw@rjwysocki.net, everywhere in MAINTAINERS and Documentation/ABI. Signed-off-by: Rafael J. Wysocki <rjw@rjwysocki.net>
2012-12-13Merge branch 'for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial Pull trivial branch from Jiri Kosina: "Usual stuff -- comment/printk typo fixes, documentation updates, dead code elimination." * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial: (39 commits) HOWTO: fix double words typo x86 mtrr: fix comment typo in mtrr_bp_init propagate name change to comments in kernel source doc: Update the name of profiling based on sysfs treewide: Fix typos in various drivers treewide: Fix typos in various Kconfig wireless: mwifiex: Fix typo in wireless/mwifiex driver messages: i2o: Fix typo in messages/i2o scripts/kernel-doc: check that non-void fcts describe their return value Kernel-doc: Convention: Use a "Return" section to describe return values radeon: Fix typo and copy/paste error in comments doc: Remove unnecessary declarations from Documentation/accounting/getdelays.c various: Fix spelling of "asynchronous" in comments. Fix misspellings of "whether" in comments. eisa: Fix spelling of "asynchronous". various: Fix spelling of "registered" in comments. doc: fix quite a few typos within Documentation target: iscsi: fix comment typos in target/iscsi drivers treewide: fix typo of "suport" in various comments and Kconfig treewide: fix typo of "suppport" in various comments ...
2012-11-19doc: fix quite a few typos within DocumentationMasanari Iida
Correct spelling typo in Documentations Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2012-10-24PM / QoS: Make it possible to expose PM QoS device flags to user spaceRafael J. Wysocki
Define two device PM QoS flags, PM_QOS_FLAG_NO_POWER_OFF and PM_QOS_FLAG_REMOTE_WAKEUP, and introduce routines dev_pm_qos_expose_flags() and dev_pm_qos_hide_flags() allowing the caller to expose those two flags to user space or to hide them from it, respectively. After the flags have been exposed, user space will see two additional sysfs attributes, pm_qos_no_power_off and pm_qos_remote_wakeup, under the device's /sys/devices/.../power/ directory. Then, writing 1 to one of them will update the PM QoS flags request owned by user space so that the corresponding flag is requested to be set. In turn, writing 0 to one of them will cause the corresponding flag in the user space's request to be cleared (however, the owners of the other PM QoS flags requests for the same device may still request the flag to be set and it may be effectively set even if user space doesn't request that). Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Reviewed-by: Jean Pihet <j-pihet@ti.com> Acked-by: mark gross <markgross@thegnar.org>
2012-05-01PM / Sleep: Add "prevent autosleep time" statistics to wakeup sourcesRafael J. Wysocki
Android uses one wakelock statistics that is only necessary for opportunistic sleep. Namely, the prevent_suspend_time field accumulates the total time the given wakelock has been locked while "automatic suspend" was enabled. Add an analogous field, prevent_sleep_time, to wakeup sources and make it behave in a similar way. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-05-01PM / Sleep: Change wakeup source statistics to follow AndroidRafael J. Wysocki
Wakeup statistics used by Android are slightly different from what we have in wakeup sources at the moment and there aren't any known users of those statistics other than Android, so modify them to make it easier for Android to switch to wakeup sources. This removes the struct wakeup_source's hit_cout field, which is very rough and therefore not very useful, and adds two new fields, wakeup_count and expire_count. The first one tracks how many times the wakeup source is activated with events_check_enabled set (which roughly corresponds to the situations when a system power transition to a sleep state is in progress and would be aborted by this wakeup source if it were the only active one at that time) and the second one is the number of times the wakeup source has been activated with a timeout that expired. Additionally, the last_time field is now updated when the wakeup source is deactivated too (previously it was only updated during the wakeup source's activation), which seems to be what Android does with the analogous counter for wakelocks. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-03-13PM / QoS: Make it possible to expose PM QoS latency constraintsRafael J. Wysocki
A runtime suspend of a device (e.g. an MMC controller) belonging to a power domain or, in a more complicated scenario, a runtime suspend of another device in the same power domain, may cause power to be removed from the entire domain. In that case, the amount of time necessary to runtime-resume the given device (e.g. the MMC controller) is often substantially greater than the time needed to run its driver's runtime resume callback. That may hurt performance in some situations, because user data may need to wait for the device to become operational, so we should make it possible to prevent that from happening. For this reason, introduce a new sysfs attribute for devices, power/pm_qos_resume_latency_us, allowing user space to specify the upper bound of the time necessary to bring the (runtime-suspended) device up after the resume of it has been requested. However, make that attribute appear only for the devices whose drivers declare support for it by calling the (new) dev_pm_qos_expose_latency_limit() helper function with the appropriate initial value of the attribute. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Reviewed-by: Kevin Hilman <khilman@ti.com> Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Acked-by: Linus Walleij <linus.walleij@linaro.org>
2011-03-15PM: Do not create wakeup sysfs files for devices that cannot wake upRafael J. Wysocki
Currently, wakeup sysfs attributes are created for all devices, regardless of whether or not they are wakeup-capable. This is excessive and complicates wakeup device identification from user space (i.e. to identify wakeup-capable devices user space has to read /sys/devices/.../power/wakeup for all devices and see if they are not empty). Fix this issue by avoiding to create wakeup sysfs files for devices that cannot wake up the system from sleep states (i.e. whose power.can_wakeup flags are unset during registration) and modify device_set_wakeup_capable() so that it adds (or removes) the relevant sysfs attributes if a device's wakeup capability status is changed. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2010-10-17PM / Runtime: Implement autosuspend supportAlan Stern
This patch (as1427) implements the "autosuspend" facility for runtime PM. A few new fields are added to the dev_pm_info structure and several new PM helper functions are defined, for telling the PM core whether or not a device uses autosuspend, for setting the autosuspend delay, and for marking periods of device activity. Drivers that do not want to use autosuspend can continue using the same helper functions as before; their behavior will not change. In addition, drivers supporting autosuspend can also call the old helper functions to get the old behavior. The details are all explained in Documentation/power/runtime_pm.txt and Documentation/ABI/testing/sysfs-devices-power. Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2010-10-17PM / Wakeup: Introduce wakeup source objects and event statistics (v3)Rafael J. Wysocki
Introduce struct wakeup_source for representing system wakeup sources within the kernel and for collecting statistics related to them. Make the recently introduced helper functions pm_wakeup_event(), pm_stay_awake() and pm_relax() use struct wakeup_source objects internally, so that wakeup statistics associated with wakeup devices can be collected and reported in a consistent way (the definition of pm_relax() is changed, which is harmless, because this function is not called directly by anyone yet). Introduce new wakeup-related sysfs device attributes in /sys/devices/.../power for reporting the device wakeup statistics. Change the global wakeup events counters event_count and events_in_progress into atomic variables, so that it is not necessary to acquire a global spinlock in pm_wakeup_event(), pm_stay_awake() and pm_relax(), which should allow us to avoid lock contention in these functions on SMP systems with many wakeup devices. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
2010-02-26PM: Add facility for advanced testing of async suspend/resumeRafael J. Wysocki
Add configuration switch CONFIG_PM_ADVANCED_DEBUG for compiling in extra PM debugging/testing code allowing one to access some PM-related attributes of devices from the user space via sysfs. If CONFIG_PM_ADVANCED_DEBUG is set, add sysfs attribute power/async for every device allowing the user space to access the device's power.async_suspend flag and modify it, if desired. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2010-02-26PM: Document device power attributes in sysfsRafael J. Wysocki
There are sysfs attributes in /sys/devices/.../power/ that haven't been documented yet in Documentation/ABI/. Document them as appropriate. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>