25 Oct, 2011
1 commit
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* 'pm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (63 commits)
PM / Clocks: Remove redundant NULL checks before kfree()
PM / Documentation: Update docs about suspend and CPU hotplug
ACPI / PM: Add Sony VGN-FW21E to nonvs blacklist.
ARM: mach-shmobile: sh7372 A4R support (v4)
ARM: mach-shmobile: sh7372 A3SP support (v4)
PM / Sleep: Mark devices involved in wakeup signaling during suspend
PM / Hibernate: Improve performance of LZO/plain hibernation, checksum image
PM / Hibernate: Do not initialize static and extern variables to 0
PM / Freezer: Make fake_signal_wake_up() wake TASK_KILLABLE tasks too
PM / Hibernate: Add resumedelay kernel param in addition to resumewait
MAINTAINERS: Update linux-pm list address
PM / ACPI: Blacklist Vaio VGN-FW520F machine known to require acpi_sleep=nonvs
PM / ACPI: Blacklist Sony Vaio known to require acpi_sleep=nonvs
PM / Hibernate: Add resumewait param to support MMC-like devices as resume file
PM / Hibernate: Fix typo in a kerneldoc comment
PM / Hibernate: Freeze kernel threads after preallocating memory
PM: Update the policy on default wakeup settings
PM / VT: Cleanup #if defined uglyness and fix compile error
PM / Suspend: Off by one in pm_suspend()
PM / Hibernate: Include storage keys in hibernation image on s390
...
22 Oct, 2011
1 commit
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Update the documentation about the interaction between the suspend (S3) call
path and the CPU hotplug infrastructure.
This patch focusses only on the activities of the freezer, cpu hotplug and
the notifications involved. It outlines how regular CPU hotplug differs from
the way it is invoked during suspend and also tries to explain the locking
involved. In addition to that, it discusses the issue of microcode update
during CPU hotplug operations.Signed-off-by: Srivatsa S. Bhat
Signed-off-by: Rafael J. Wysocki
17 Oct, 2011
4 commits
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There is a problem with the current ordering of hibernate code which
leads to deadlocks in some filesystems' memory shrinkers. Namely,
some filesystems use freezable kernel threads that are inactive when
the hibernate memory preallocation is carried out. Those same
filesystems use memory shrinkers that may be triggered by the
hibernate memory preallocation. If those memory shrinkers wait for
the frozen kernel threads, the hibernate process deadlocks (this
happens with XFS, for one example).Apparently, it is not technically viable to redesign the filesystems
in question to avoid the situation described above, so the only
possible solution of this issue is to defer the freezing of kernel
threads until the hibernate memory preallocation is done, which is
implemented by this change.Unfortunately, this requires the memory preallocation to be done
before the "prepare" stage of device freeze, so after this change the
only way drivers can allocate additional memory for their freeze
routines in a clean way is to use PM notifiers.Reported-by: Christoph
Signed-off-by: Rafael J. Wysocki -
This patch (as1485) documents a change to the kernel's default wakeup
policy. Devices that forward wakeup requests between buses should be
enabled for wakeup by default.Signed-off-by: Alan Stern
Signed-off-by: Rafael J. Wysocki -
Record S3 failure time about each reason and the latest two failed
devices' names in S3 progress.
We can check it through 'suspend_stats' entry in debugfs.The motivation of the patch:
We are enabling power features on Medfield. Comparing with PC/notebook,
a mobile enters/exits suspend-2-ram (we call it s3 on Medfield) far
more frequently. If it can't enter suspend-2-ram in time, the power
might be used up soon.We often find sometimes, a device suspend fails. Then, system retries
s3 over and over again. As display is off, testers and developers
don't know what happens.Some testers and developers complain they don't know if system
tries suspend-2-ram, and what device fails to suspend. They need
such info for a quick check. The patch adds suspend_stats under
debugfs for users to check suspend to RAM statistics quickly.If not using this patch, we have other methods to get info about
what device fails. One is to turn on CONFIG_PM_DEBUG, but users
would get too much info and testers need recompile the system.In addition, dynamic debug is another good tool to dump debug info.
But it still doesn't match our utilization scenario closely.
1) user need write a user space parser to process the syslog output;
2) Our testing scenario is we leave the mobile for at least hours.
Then, check its status. No serial console available during the
testing. One is because console would be suspended, and the other
is serial console connecting with spi or HSU devices would consume
power. These devices are powered off at suspend-2-ram.Signed-off-by: ShuoX Liu
Signed-off-by: Rafael J. Wysocki -
* pm-runtime:
PM / Runtime: Handle .runtime_suspend() failure correctly
PM / Runtime: Fix kerneldoc comment for rpm_suspend()
PM / Runtime: Update document about callbacks
11 Oct, 2011
1 commit
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Support for device power domains has been introduced in
commit 9659cc0678b954f187290c6e8b247a673c5d37e1 (PM: Make
system-wide PM and runtime PM treat subsystems consistently),
also power domain callbacks will take precedence over subsystem ones
from commit 4d27e9dcff00a6425d779b065ec8892e4f391661(PM: Make
power domain callbacks take precedence over subsystem ones).So update part of "Device Runtime PM Callbacks" in
Documentation/power/runtime_pm.txt.Signed-off-by: Ming Lei
Signed-off-by: Rafael J. Wysocki
08 Oct, 2011
2 commits
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* pm-qos:
PM / QoS: Update Documentation for the pm_qos and dev_pm_qos frameworks
PM / QoS: Add function dev_pm_qos_read_value() (v3)
PM QoS: Add global notification mechanism for device constraints
PM QoS: Implement per-device PM QoS constraints
PM QoS: Generalize and export constraints management code
PM QoS: Reorganize data structs
PM QoS: Code reorganization
PM QoS: Minor clean-ups
PM QoS: Move and rename the implementation files -
* pm-runtime:
PM / Tracing: build rpm-traces.c only if CONFIG_PM_RUNTIME is set
PM / Runtime: Replace dev_dbg() with trace_rpm_*()
PM / Runtime: Introduce trace points for tracing rpm_* functions
PM / Runtime: Don't run callbacks under lock for power.irq_safe set
USB: Add wakeup info to debugging messages
PM / Runtime: pm_runtime_idle() can be called in atomic context
PM / Runtime: Add macro to test for runtime PM events
PM / Runtime: Add might_sleep() to runtime PM functions
05 Oct, 2011
1 commit
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Update the documentation for the recently updated pm_qos API, kernel
and user space. Add documentation for the per-device PM QoS
(dev_pm_qos) framework API.Signed-off-by: Jean Pihet
Signed-off-by: Rafael J. Wysocki
28 Sep, 2011
1 commit
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There are numerous broken references to Documentation files (in other
Documentation files, in comments, etc.). These broken references are
caused by typo's in the references, and by renames or removals of the
Documentation files. Some broken references are simply odd.Fix these broken references, sometimes by dropping the irrelevant text
they were part of.Signed-off-by: Paul Bolle
Signed-off-by: Jiri Kosina
22 Sep, 2011
1 commit
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Add to pm_runtime_idle the list of functions that can be called
in atomic context if pm_runtime_irq_safe() has been called for the
device.Signed-off-by: Ming Lei
Signed-off-by: Rafael J. Wysocki
25 Aug, 2011
1 commit
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The description of pm_runtime_irq_safe() has to be updated to follow
the code after commit 02b2677 (PM / Runtime: Allow _put_sync() from
interrupts-disabled context).Signed-off-by: Rafael J. Wysocki
Acked-by: Kevin Hilman
14 Aug, 2011
1 commit
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Some of the entry points to pm runtime are not safe to
call in atomic context unless pm_runtime_irq_safe() has
been called. Inspecting the code, it is not immediately
obvious that the functions sleep at all, as they run
inside a spin_lock_irqsave, but under some conditions
they can drop the lock and turn on irqs.If a driver incorrectly calls the pm_runtime apis, it can
cause sleeping and irq processing when it expects to stay
in atomic context.Add might_sleep_if to the majority of the __pm_runtime_* entry points
to enforce correct usage.Add pm_runtime_put_sync_autosuspend to the list of
functions that can be called in atomic context.Signed-off-by: Colin Cross
Reviewed-by: Kevin Hilman
Signed-off-by: Rafael J. Wysocki
06 Aug, 2011
1 commit
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Currently the use of pm_runtime_put_sync() is not safe from
interrupts-disabled context because rpm_idle() will release the
spinlock and enable interrupts for the idle callbacks. This enables
interrupts during a time where interrupts were expected to be
disabled, and can have strange side effects on drivers that expected
interrupts to be disabled.This is not a bug since the documentation clearly states that only
_put_sync_suspend() is safe in IRQ-safe mode.However, pm_runtime_put_sync() could be made safe when in IRQ-safe
mode by releasing the spinlock but not re-enabling interrupts, which
is what this patch aims to do.Problem was found when using some buggy drivers that set
pm_runtime_irq_safe() and used _put_sync() in interrupts-disabled
context.Reported-by: Colin Cross
Tested-by: Nishanth Menon
Signed-off-by: Kevin Hilman
Signed-off-by: Rafael J. Wysocki
16 Jul, 2011
3 commits
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* pm-runtime:
OMAP: PM: disable idle on suspend for GPIO and UART
OMAP: PM: omap_device: add API to disable idle on suspend
OMAP: PM: omap_device: add system PM methods for PM domain handling
OMAP: PM: omap_device: conditionally use PM domain runtime helpers
PM / Runtime: Add new helper function: pm_runtime_status_suspended()
PM / Runtime: Consistent utilization of deferred_resume
PM / Runtime: Prevent runtime_resume from racing with probe
PM / Runtime: Replace "run-time" with "runtime" in documentation
PM / Runtime: Improve documentation of enable, disable and barrier
PM: Limit race conditions between runtime PM and system sleep (v2)
PCI / PM: Detect early wakeup in pci_pm_prepare()
PM / Runtime: Return special error code if runtime PM is disabled
PM / Runtime: Update documentation of interactions with system sleep -
* pm-domains: (33 commits)
ARM / shmobile: Return -EBUSY from A4LC power off if A3RV is active
PM / Domains: Take .power_off() error code into account
ARM / shmobile: Use genpd_queue_power_off_work()
ARM / shmobile: Use pm_genpd_poweroff_unused()
PM / Domains: Introduce function to power off all unused PM domains
PM / Domains: Queue up power off work only if it is not pending
PM / Domains: Improve handling of wakeup devices during system suspend
PM / Domains: Do not restore all devices on power off error
PM / Domains: Allow callbacks to execute all runtime PM helpers
PM / Domains: Do not execute device callbacks under locks
PM / Domains: Make failing pm_genpd_prepare() clean up properly
PM / Domains: Set device state to "active" during system resume
ARM: mach-shmobile: sh7372 A3RV requires A4LC
PM / Domains: Export pm_genpd_poweron() in header
ARM: mach-shmobile: sh7372 late pm domain off
ARM: mach-shmobile: Runtime PM late init callback
ARM: mach-shmobile: sh7372 D4 support
ARM: mach-shmobile: sh7372 A4MP support
ARM: mach-shmobile: sh7372: make sure that fsi is peripheral of spu2
ARM: mach-shmobile: sh7372 A3SG support
... -
cpufreq table allocated by opp_init_cpufreq_table is better
freed by OPP layer itself. This allows future modifications to
the table handling to be transparent to the users.Signed-off-by: Nishanth Menon
Acked-by: Kevin Hilman
Signed-off-by: Rafael J. Wysocki
12 Jul, 2011
1 commit
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This boolean function simply returns whether or not the runtime status
of the device is 'suspended'. Unlike pm_runtime_suspended(), this
function returns the runtime status whether or not runtime PM for the
device has been disabled or not.Also add entry to Documentation/power/runtime.txt
Signed-off-by: Kevin Hilman
Signed-off-by: Rafael J. Wysocki
06 Jul, 2011
3 commits
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The runtime PM documentation and kerneldoc comments sometimes spell
"runtime" with a dash (i.e. "run-time"). Replace all of those
instances with "runtime" to make the naming consistent.Signed-off-by: Rafael J. Wysocki
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The runtime PM documentation in Documentation/power/runtime_pm.txt
doesn't say that pm_runtime_enable() and pm_runtime_disable() work by
operating on power.disable_depth, which is wrong, because the
possibility of nesting disables doesn't follow from the description
of these functions. Also, there is no description of
pm_runtime_barrier() at all in the document, which is confusing.
Improve the documentation by fixing those issues.Signed-off-by: Rafael J. Wysocki
-
One of the roles of the PM core is to prevent different PM callbacks
executed for the same device object from racing with each other.
Unfortunately, after commit e8665002477f0278f84f898145b1f141ba26ee26
(PM: Allow pm_runtime_suspend() to succeed during system suspend)
runtime PM callbacks may be executed concurrently with system
suspend/resume callbacks for the same device.The main reason for commit e8665002477f0278f84f898145b1f141ba26ee26
was that some subsystems and device drivers wanted to use runtime PM
helpers, pm_runtime_suspend() and pm_runtime_put_sync() in
particular, for carrying out the suspend of devices in their
.suspend() callbacks. However, as it's been determined recently,
there are multiple reasons not to do so, inlcuding:* The caller really doesn't control the runtime PM usage counters,
because user space can access them through sysfs and effectively
block runtime PM. That means using pm_runtime_suspend() or
pm_runtime_get_sync() to suspend devices during system suspend
may or may not work.* If a driver calls pm_runtime_suspend() from its .suspend()
callback, it causes the subsystem's .runtime_suspend() callback to
be executed, which leads to the call sequence:subsys->suspend(dev)
driver->suspend(dev)
pm_runtime_suspend(dev)
subsys->runtime_suspend(dev)recursive from the subsystem's point of view. For some subsystems
that may actually work (e.g. the platform bus type), but for some
it will fail in a rather spectacular fashion (e.g. PCI). In each
case it means a layering violation.* Both the subsystem and the driver can provide .suspend_noirq()
callbacks for system suspend that can do whatever the
.runtime_suspend() callbacks do just fine, so it really isn't
necessary to call pm_runtime_suspend() during system suspend.* The runtime PM's handling of wakeup devices is usually different
from the system suspend's one, so .runtime_suspend() may simply be
inappropriate for system suspend.* System suspend is supposed to work even if CONFIG_PM_RUNTIME is
unset.* The runtime PM workqueue is frozen before system suspend, so if
whatever the driver is going to do during system suspend depends
on it, that simply won't work.Still, there is a good reason to allow pm_runtime_resume() to
succeed during system suspend and resume (for instance, some
subsystems and device drivers may legitimately use it to ensure that
their devices are in full-power states before suspending them).
Moreover, there is no reason to prevent runtime PM callbacks from
being executed in parallel with the system suspend/resume .prepare()
and .complete() callbacks and the code removed by commit
e8665002477f0278f84f898145b1f141ba26ee26 went too far in this
respect. On the other hand, runtime PM callbacks, including
.runtime_resume(), must not be executed during system suspend's
"late" stage of suspending devices and during system resume's "early"
device resume stage.Taking all of the above into consideration, make the PM core
acquire a runtime PM reference to every device and resume it if
there's a runtime PM resume request pending right before executing
the subsystem-level .suspend() callback for it. Make the PM core
drop references to all devices right after executing the
subsystem-level .resume() callbacks for them. Additionally,
make the PM core disable the runtime PM framework for all devices
during system suspend, after executing the subsystem-level .suspend()
callbacks for them, and enable the runtime PM framework for all
devices during system resume, right before executing the
subsystem-level .resume() callbacks for them.Signed-off-by: Rafael J. Wysocki
Acked-by: Kevin Hilman
02 Jul, 2011
6 commits
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Some callers of pm_runtime_get_sync() and other runtime PM helper
functions, scsi_autopm_get_host() and scsi_autopm_get_device() in
particular, need to distinguish error codes returned when runtime PM
is disabled (i.e. power.disable_depth is nonzero for the given
device) from error codes returned in other situations. For this
reason, make the runtime PM helper functions return -EACCES when
power.disable_depth is nonzero and ensure that this error code
won't be returned by them in any other circumstances. Modify
scsi_autopm_get_host() and scsi_autopm_get_device() to check the
error code returned by pm_runtime_get_sync() and ignore -EACCES.Signed-off-by: Rafael J. Wysocki
-
The documents describing the interactions between runtime PM and
system sleep generally refer to the model in which the system sleep
state is entered through a global firmware or hardware operation.
As a result, some recommendations given in there are not entirely
suitable for systems in which this is not the case. Update the
documentation to take the existence of those systems into account.Signed-off-by: Rafael J. Wysocki
Reviewed-by: Kevin Hilman -
Introduce generic "noirq" power management callback routines for
subsystems in addition to the "regular" generic PM callback routines.The new routines will be used, among other things, for implementing
system-wide PM transitions support for generic PM domains.Signed-off-by: Rafael J. Wysocki
-
The naming convention used by commit 7538e3db6e015e890825fbd9f86599b
(PM: Add support for device power domains), which introduced the
struct dev_power_domain type for representing device power domains,
evidently confuses some developers who tend to think that objects
of this type must correspond to "power domains" as defined by
hardware, which is not the case. Namely, at the kernel level, a
struct dev_power_domain object can represent arbitrary set of devices
that are mutually dependent power management-wise and need not belong
to one hardware power domain. To avoid that confusion, rename struct
dev_power_domain to struct dev_pm_domain and rename the related
pointers in struct device and struct pm_clk_notifier_block from
pwr_domain to pm_domain.Signed-off-by: Rafael J. Wysocki
Acked-by: Kevin Hilman -
Commit e1866b33b1e89f077b7132daae3dfd9a594e9a1a (PM / Runtime: Rework
runtime PM handling during driver removal) forgot to update the
documentation in Documentation/power/runtime_pm.txt to match the new
code in drivers/base/dd.c. Update that documentation to match the
code it describes.Signed-off-by: Rafael J. Wysocki
Reviewed-by: Kevin Hilman -
Replace reference to pm_runtime_idle_sync() in the driver core with
pm_runtime_put_sync() which is used in the code.Signed-off-by: Kevin Hilman
Signed-off-by: Rafael J. Wysocki
22 Jun, 2011
3 commits
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Commit 4d27e9dcff00a6425d779b065ec8892e4f391661 (PM: Make power
domain callbacks take precedence over subsystem ones) forgot to
update the device power management documentation to take changes
made by it into account. Correct that mistake.Signed-off-by: Rafael J. Wysocki
-
The part of Documentation/power/devices.txt regarding sysdevs is not
valid any more after commit 2e711c04dbbf7a7732a3f7073b1fc285d12b369d
(PM: Remove sysdev suspend, resume and shutdown operations), so
remove it.Signed-off-by: Rafael J. Wysocki
-
Commit e8665002477f0278f84f898145b1f141ba26ee26 (PM: Allow
pm_runtime_suspend() to succeed during system suspend) removed usage
count increment across system PM.Update doc to reflect this.
Signed-off-by: Kevin Hilman
Signed-off-by: Rafael J. Wysocki
27 May, 2011
1 commit
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supply_regulator_dev (using a struct pointer) has been deprecated in favour
of supply_regulator (using a regulator name) for quite a few releases
now with a warning generated if it is used and there are no current in tree
users so just remove the code.Signed-off-by: Mark Brown
Signed-off-by: Liam Girdwood
18 May, 2011
1 commit
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If device drivers allocate substantial amounts of memory (above 1 MB)
in their hibernate .freeze() callbacks (or in their legacy suspend
callbcks during hibernation), the subsequent creation of hibernate
image may fail due to the lack of memory. This is the case, because
the drivers' .freeze() callbacks are executed after the hibernate
memory preallocation has been carried out and the preallocated amount
of memory may be too small to cover the new driver allocations.
Unfortunately, the drivers' .prepare() callbacks also are executed
after the hibernate memory preallocation has completed, so they are
not suitable for allocating additional memory either. Thus the only
way a driver can safely allocate memory during hibernation is to use
a hibernate/suspend notifier. However, the notifiers are called
before the freezing of user space and the drivers wanting to use them
for allocating additional memory may not know how much memory needs
to be allocated at that point.To let device drivers overcome this difficulty rework the hibernation
sequence so that the memory preallocation is carried out after the
drivers' .prepare() callbacks have been executed, so that the
.prepare() callbacks can be used for allocating additional memory
to be used by the drivers' .freeze() callbacks. Update documentation
to match the new behavior of the code.Signed-off-by: Rafael J. Wysocki
31 Mar, 2011
1 commit
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Fixes generated by 'codespell' and manually reviewed.
Signed-off-by: Lucas De Marchi
15 Mar, 2011
4 commits
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Remove repetition of "called swsusp".
Signed-off-by: Alexandre Courbot
Signed-off-by: Rafael J. Wysocki -
The code handling system-wide power transitions (eg. suspend-to-RAM)
can in theory execute callbacks provided by the device's bus type,
device type and class in each phase of the power transition. In
turn, the runtime PM core code only calls one of those callbacks at
a time, preferring bus type callbacks to device type or class
callbacks and device type callbacks to class callbacks.It seems reasonable to make them both behave in the same way in that
respect. Moreover, even though a device may belong to two subsystems
(eg. bus type and device class) simultaneously, in practice power
management callbacks for system-wide power transitions are always
provided by only one of them (ie. if the bus type callbacks are
defined, the device class ones are not and vice versa). Thus it is
possible to modify the code handling system-wide power transitions
so that it follows the core runtime PM code (ie. treats the
subsystem callbacks as mutually exclusive).On the other hand, the core runtime PM code will choose to execute,
for example, a runtime suspend callback provided by the device type
even if the bus type's struct dev_pm_ops object exists, but the
runtime_suspend pointer in it happens to be NULL. This is confusing,
because it may lead to the execution of callbacks from different
subsystems during different operations (eg. the bus type suspend
callback may be executed during runtime suspend of the device, while
the device type callback will be executed during system suspend).Make all of the power management code treat subsystem callbacks in
a consistent way, such that:
(1) If the device's type is defined (eg. dev->type is not NULL)
and its pm pointer is not NULL, the callbacks from dev->type->pm
will be used.
(2) If dev->type is NULL or dev->type->pm is NULL, but the device's
class is defined (eg. dev->class is not NULL) and its pm pointer
is not NULL, the callbacks from dev->class->pm will be used.
(3) If dev->type is NULL or dev->type->pm is NULL and dev->class is
NULL or dev->class->pm is NULL, the callbacks from dev->bus->pm
will be used provided that both dev->bus and dev->bus->pm are
not NULL.Signed-off-by: Rafael J. Wysocki
Acked-by: Kevin Hilman
Reasoning-sounds-sane-to: Grant Likely
Acked-by: Greg Kroah-Hartman -
The platform bus type is often used to handle Systems-on-a-Chip (SoC)
where all devices are represented by objects of type struct
platform_device. In those cases the same "platform" device driver
may be used with multiple different system configurations, but the
actions needed to put the devices it handles into a low-power state
and back into the full-power state may depend on the design of the
given SoC. The driver, however, cannot possibly include all the
information necessary for the power management of its device on all
the systems it is used with. Moreover, the device hierarchy in its
current form also is not suitable for representing this kind of
information.The patch below attempts to address this problem by introducing
objects of type struct dev_power_domain that can be used for
representing power domains within a SoC. Every struct
dev_power_domain object provides a sets of device power
management callbacks that can be used to perform what's needed for
device power management in addition to the operations carried out by
the device's driver and subsystem.Namely, if a struct dev_power_domain object is pointed to by the
pwr_domain field in a struct device, the callbacks provided by its
ops member will be executed in addition to the corresponding
callbacks provided by the device's subsystem and driver during all
power transitions.Signed-off-by: Rafael J. Wysocki
Tested-and-acked-by: Kevin Hilman -
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
24 Dec, 2010
2 commits
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basic-pm-debugging.txt is located in Documentation/power/ not
Documents/power/. Change the references in
Documentation/power/drivers-testing.txt to reflect the location.Signed-off-by: Jon Mason
Signed-off-by: Rafael J. Wysocki -
This patch (as1431c) makes the synchronous runtime-PM interface
suitable for use in interrupt handlers. Subsystems can call the new
pm_runtime_irq_safe() function to tell the PM core that a device's
runtime_suspend and runtime_resume callbacks should be invoked with
interrupts disabled and the spinlock held. This permits the
pm_runtime_get_sync() and the new pm_runtime_put_sync_suspend()
routines to be called from within interrupt handlers.When a device is declared irq-safe in this way, the PM core increments
the parent's usage count, so the parent will never be runtime
suspended. This prevents difficult situations in which an irq-safe
device can't resume because it is forced to wait for its non-irq-safe
parent.Signed-off-by: Alan Stern
Signed-off-by: Rafael J. Wysocki
