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>
* 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
* 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
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>
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>
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>
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>
Drop an excess "`" from Documentation/driver-api/pm/devices.rst.
Fixes: 2728b2d2e5 (PM / core / docs: Convert sleep states API document to reST)
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
There is a better way to represent structure references than it was
done in device.rst by commit 730c4c0530 (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: 730c4c0530 (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>
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>
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>
