summaryrefslogtreecommitdiff
path: root/Documentation/driver-api/pm
AgeCommit message (Collapse)AuthorFilesLines
2020-04-26PM: sleep: Helpful edits for devices.rst documentationAlan Stern1-42/+52
Here are some minor edits of the devices.rst documentation file, intended to improve the clarity and add a couple of missing details. Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2020-04-24Documentation: PM: sleep: Update driver flags documentationRafael J. Wysocki1-47/+92
Update the documentation of the driver flags for system-wide power management to reflect the current code flows and be more consistent. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2020-04-24PM: sleep: core: Rename DPM_FLAG_LEAVE_SUSPENDEDRafael J. Wysocki1-2/+2
Rename DPM_FLAG_LEAVE_SUSPENDED to DPM_FLAG_MAY_SKIP_RESUME which matches its purpose more closely. No functional impact. Suggested-by: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Wolfram Sang <wsa@the-dreams.de> # for I2C Acked-by: Alan Stern <stern@rowland.harvard.edu> Acked-by: Bjorn Helgaas <bhelgaas@google.com>
2020-04-24PM: sleep: core: Rename DPM_FLAG_NEVER_SKIPRafael J. Wysocki1-3/+3
Rename DPM_FLAG_NEVER_SKIP to DPM_FLAG_NO_DIRECT_COMPLETE which matches its purpose more closely. No functional impact. Suggested-by: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Bjorn Helgaas <bhelgaas@google.com> # for PCI parts Acked-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com> Acked-by: Alan Stern <stern@rowland.harvard.edu> Acked-by: Bjorn Helgaas <bhelgaas@google.com> Acked-by: Alex Deucher <alexander.deucher@amd.com>
2019-07-17docs: remove extra conf.py filesMauro Carvalho Chehab1-10/+0
Now that the latex_documents are handled automatically, we can remove those extra conf.py files. Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
2019-06-15docs: power: convert docs to ReST and rename to *.rstMauro Carvalho Chehab1-3/+3
Convert the PM documents to ReST, in order to allow them to build with Sphinx. The conversion is actually: - add blank lines and indentation in order to identify paragraphs; - fix tables markups; - add some lists markups; - mark literal blocks; - adjust title markups. At its new index.rst, let's add a :orphan: while this is not linked to the main index.rst file, in order to avoid build warnings. Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Acked-by: Mark Brown <broonie@kernel.org> Acked-by: Srivatsa S. Bhat (VMware) <srivatsa@csail.mit.edu>
2019-04-08Documentation: PM: Unify copyright noticesRafael J. Wysocki3-8/+13
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. Wysocki5-0/+10
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>
2019-01-18Documentation: driver-api: PM: Add cpuidle documentRafael J. Wysocki2-3/+286
Replace the remaining documents under Documentation/cpuidle/ with one more complete governor and driver API document for cpuidle under Documentation/driver-api/pm/. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
2018-12-06doc:process: add links where missingFederico Vaga1-0/+2
Some documents are refering to others without links. With this patch I add those missing links. This patch affects only documents under process/ and labels where necessary. Signed-off-by: Federico Vaga <federico.vaga@vaga.pv.it> Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2018-01-03PM / core: Direct DPM_FLAG_LEAVE_SUSPENDED handlingRafael J. Wysocki1-0/+9
Make the PM core handle DPM_FLAG_LEAVE_SUSPENDED directly for devices whose "noirq", "late" and "early" driver callbacks are invoked directly by it. Namely, make it skip all of the system-wide resume callbacks for such devices with DPM_FLAG_LEAVE_SUSPENDED set if they are in runtime suspend during the "noirq" phase of system-wide suspend (or analogous) transitions or the system transition under way is a proper suspend (rather than anything related to hibernation) and the device's wakeup settings are compatible with runtime PM (that is, the device cannot generate wakeup signals at all or it is allowed to wake up the system from sleep). Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2018-01-03PM / core: Direct DPM_FLAG_SMART_SUSPEND optimizationRafael J. Wysocki1-8/+10
Make the PM core avoid invoking the "late" and "noirq" system-wide suspend (or analogous) callbacks provided by device drivers directly for devices with DPM_FLAG_SMART_SUSPEND set that are in runtime suspend during the "late" and "noirq" phases of system-wide suspend (or analogous) transitions. That is only done for devices without any middle-layer "late" and "noirq" suspend callbacks (to avoid confusing the middle layer if there is one). The underlying observation is that runtime PM is disabled for devices during the "late" and "noirq" system-wide suspend phases, so if they remain in runtime suspend from the "late" phase forward, it doesn't make sense to invoke the "late" and "noirq" callbacks provided by the drivers for them (arguably, the device is already suspended and in the right state). Thus, if the remaining driver suspend callbacks are to be invoked directly by the core, they can be skipped. This change really makes it possible for, say, platform device drivers to re-use runtime PM suspend and resume callbacks by pointing ->suspend_late and ->resume_early, respectively (and possibly the analogous hibernation-related callback pointers too), to them without adding any extra "is the device already suspended?" type of checks to the callback routines, as long as they will be invoked directly by the core. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2017-11-27PM / core: Add LEAVE_SUSPENDED driver flagRafael J. Wysocki1-2/+25
Define and document a new driver flag, DPM_FLAG_LEAVE_SUSPENDED, to instruct the PM core and middle-layer (bus type, PM domain, etc.) code that it is desirable to leave the device in runtime suspend after system-wide transitions to the working state (for example, the device may be slow to resume and it may be better to avoid resuming it right away). Generally, the middle-layer code involved in the handling of the device is expected to indicate to the PM core whether or not the device may be left in suspend with the help of the device's power.may_skip_resume status bit. That has to happen in the "noirq" phase of the preceding system suspend (or analogous) transition. The middle layer is then responsible for handling the device as appropriate in its "noirq" resume callback which is executed regardless of whether or not the device may be left suspended, but the other resume callbacks (except for ->complete) will be skipped automatically by the core if the device really can be left in suspend. The additional power.must_resume status bit introduced for the implementation of this mechanisn is used internally by the PM core to track the requirement to resume the device (which may depend on its children etc). Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
2017-11-13Merge branch 'pm-core'Rafael J. Wysocki1-0/+34
* pm-core: ACPI / PM: Take SMART_SUSPEND driver flag into account PCI / PM: Take SMART_SUSPEND driver flag into account PCI / PM: Drop unnecessary invocations of pcibios_pm_ops callbacks PM / core: Add SMART_SUSPEND driver flag PCI / PM: Use the NEVER_SKIP driver flag PM / core: Add NEVER_SKIP and SMART_PREPARE driver flags PM / core: Convert timers to use timer_setup() PM / core: Fix kerneldoc comments of four functions PM / core: Drop legacy class suspend/resume operations
2017-11-13Merge branch 'pm-sleep'Rafael J. Wysocki1-1/+24
* pm-sleep: freezer: Fix typo in freezable_schedule_timeout() comment PM / s2idle: Clear the events_check_enabled flag PM / sleep: Remove pm_complete_with_resume_check() PM: ARM: locomo: Drop suspend and resume bus type callbacks PM: Use a more common logging style PM: Document rules on using pm_runtime_resume() in system suspend callbacks
2017-11-06PM / core: Add SMART_SUSPEND driver flagRafael J. Wysocki1-0/+20
Define and document a SMART_SUSPEND flag to instruct bus types and PM domains that the system suspend callbacks provided by the driver can cope with runtime-suspended devices, so from the driver's perspective it should be safe to leave devices in runtime suspend during system suspend. Setting that flag may also cause middle-layer code (bus types, PM domains etc.) to skip invocations of the ->suspend_late and ->suspend_noirq callbacks provided by the driver if the device is in runtime suspend at the beginning of the "late" phase of the system-wide suspend transition, in which case the driver's system-wide resume callbacks may be invoked back-to-back with its ->runtime_suspend callback, so the driver has to be able to cope with that too. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
2017-11-06PM / core: Add NEVER_SKIP and SMART_PREPARE driver flagsRafael J. Wysocki1-0/+14
The motivation for this change is to provide a way to work around a problem with the direct-complete mechanism used for avoiding system suspend/resume handling for devices in runtime suspend. The problem is that some middle layer code (the PCI bus type and the ACPI PM domain in particular) returns positive values from its system suspend ->prepare callbacks regardless of whether the driver's ->prepare returns a positive value or 0, which effectively prevents drivers from being able to control the direct-complete feature. Some drivers need that control, however, and the PCI bus type has grown its own flag to deal with this issue, but since it is not limited to PCI, it is better to address it by adding driver flags at the core level. To that end, add a driver_flags field to struct dev_pm_info for flags that can be set by device drivers at the probe time to inform the PM core and/or bus types, PM domains and so on on the capabilities and/or preferences of device drivers. Also add two static inline helpers for setting that field and testing it against a given set of flags and make the driver core clear it automatically on driver remove and probe failures. Define and document two PM driver flags related to the direct- complete feature: NEVER_SKIP and SMART_PREPARE that can be used, respectively, to indicate to the PM core that the direct-complete mechanism should never be used for the device and to inform the middle layer code (bus types, PM domains etc) that it can only request the PM core to use the direct-complete mechanism for the device (by returning a positive value from its ->prepare callback) if it also has been requested by the driver. While at it, make the core check pm_runtime_suspended() when setting power.direct_complete so that it doesn't need to be checked by ->prepare callbacks. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Acked-by: Bjorn Helgaas <bhelgaas@google.com> Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
2017-10-21PM: docs: Fix formatting typo in devices.rstRafael J. Wysocki1-1/+1
There is one word too many under formatting markup in one place in device.rst, so fix it. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2017-10-09Merge back suspend/resume/hibernate material for v4.15.Rafael J. Wysocki1-1/+24
2017-09-23PM: Document rules on using pm_runtime_resume() in system suspend callbacksRafael J. Wysocki1-1/+24
It quite often is necessary to resume devices from runtime suspend during system suspend for various reasons (for example, if their wakeup settings need to be changed), but that requires middle-layer or subsystem code to follow additional rules which currently are not clearly documented. Namely, if a driver calls pm_runtime_resume() for the device from its ->suspend (or equivalent) system sleep callback, that may not work if the middle layer above it has updated the state of the device from its ->prepare or ->suspend callbacks already in an incompatible way. For this reason, all middle layers must follow the rule that, until the ->suspend callback provided by the device's driver is invoked, the only way in which the device's state can be updated is by calling pm_runtime_resume() for it, if necessary. Fortunately enough, all middle layers in the code base today follow this rule, but it is not explicitly stated anywhere, so do that. Note that calling pm_runtime_resume() from the ->suspend callback of a driver will cause the ->runtime_resume callback provided by the middle layer to be invoked, but the rule above guarantees that this callback will nest properly with the middle layer's ->suspend callback and it will play well with the ->prepare one invoked before. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
2017-09-19PM: docs: Drop an excess character from devices.rstRafael J. Wysocki1-1/+1
Drop an excess "`" from Documentation/driver-api/pm/devices.rst. Fixes: 2728b2d2e5be (PM / core / docs: Convert sleep states API document to reST) Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2017-02-21PM / docs: Fix structure references in device.rstRafael J. Wysocki1-34/+38
There is a better way to represent structure references than it was done in device.rst by commit 730c4c053012 (PM / sleep / docs: Convert PM notifiers document to reST), which is to use "struct name" as a link caption (e.g. :c:type:`struct device <device>`). That will cause sphinx to generate a proper reference to the data type in question (struct device in the example above) and "struct name" will work as the link in the HTML output. Fix device.rst by using that convention where applicable. Fixes: 730c4c053012 (PM / sleep / docs: Convert PM notifiers document to reST) Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2017-02-06PM / sleep / docs: Convert PM notifiers document to reSTRafael J. Wysocki3-1/+72
Move the document describing PM notifiers (used during system sleep state transitions) to Documentation/driver-api/pm/, convert it to reST and update it to use current terminology. Also replace the remaining references to the old version of it in .txt documents with references to the new one. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2017-02-06PM / core / docs: Convert sleep states API document to reSTRafael J. Wysocki4-0/+762
Move the document describing the system sleep state transitions API for devices to Documentation/driver-api/pm/, convert it to reST and update it to use current terminology. Also remove the remaining reference to the old version of it from pm.h. The new document still contains references to some documents in the .txt format that will be converted later. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Jonathan Corbet <corbet@lwn.net>