Document the fact that the autosuspend delay and enable helpers may
change the power.usage_count and resume or suspend a device depending on
the values of power.autosuspend_delay and power.use_autosuspend.
Note that this means that a driver must disable autosuspend before
disabling runtime pm on probe errors and on driver unbind if the device
is to be suspended upon return (as a negative delay may otherwise keep
the device resumed).
Signed-off-by: Johan Hovold <johan@kernel.org>
Acked-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Update the autosuspend documentation which claimed that the autosuspend
delay is not taken into account when using the non-autosuspend helper
functions, something which is no longer true since commit d66e6db28d
("PM / Runtime: Respect autosuspend when idle triggers suspend").
This specifically means that drivers must now disable autosuspend before
disabling runtime pm in probe error paths and remove callbacks if
pm_runtime_put_sync was being used to suspend the device before
returning. (If an idle callback can prevent suspend,
pm_runtime_put_sync_suspend must be used instead of pm_runtime_put_sync
as before.)
Also remove the claim that the autosuspend helpers behave "just like
the non-autosuspend counterparts", something which have never really
been true as some of the latter use idle notifications.
Signed-off-by: Johan Hovold <johan@kernel.org>
Acked-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Christophe Jaillet <christophe.jaillet@wanadoo.fr>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
The previous patch renamed several files that are cross-referenced
along the Kernel documentation. Adjust the links to point to
the right places.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Put a reminder that during device removal drivers should revert all PM
runtime changes from the probe.
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Introduce a new runtime PM function, pm_runtime_get_if_in_use(),
that will increment the device's runtime PM usage counter and
return 1 if its status is RPM_ACTIVE and its usage counter
is greater than 0 at the same time (0 will be returned otherwise).
This is useful for things that should only be done if the device
is active (from the runtime PM perspective) and used by somebody
(as indicated by the usage counter) already and they are not worth
bothering otherwise.
Requested-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Don't unset the direct_complete flag on devices that have runtime PM
disabled, if they are runtime suspended.
This is needed because otherwise ancestor devices wouldn't be able to
do direct_complete without adding runtime PM support to all its
descendants.
Also removes pm_runtime_suspended_if_enabled() because it's now unused.
Signed-off-by: Tomeu Vizoso <tomeu.vizoso@collabora.com>
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
The sh_eth driver has come up with an issue where the runtime_pm
code suspends it during the probe() method due to the network
device registration re-calling into the driver.
Add a note about this into the documentation.
Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk>
Signed-off-by: Ben Hutchings <ben.hutchings@codethink.co.uk>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Pull ARM updates from Russell King:
"The major updates included in this update are:
- Clang compatible stack pointer accesses by Behan Webster.
- SA11x0 updates from Dmitry Eremin-Solenikov.
- kgdb handling of breakpoints with read-only text/modules
- Support for Privileged-no-execute feature on ARMv7 to prevent
userspace code execution by the kernel.
- AMBA primecell bus handling of irq-safe runtime PM
- Unwinding support for memset/memzero/memmove/memcpy functions
- VFP fixes for Krait CPUs and improvements in detecting the VFP
architecture
- A number of code cleanups (using pr_*, removing or reducing the
severity of a couple of kernel messages, splitting ftrace asm code
out to a separate file, etc.)
- Add machine name to stack dump output"
* 'for-linus' of git://ftp.arm.linux.org.uk/~rmk/linux-arm: (62 commits)
ARM: 8247/2: pcmcia: sa1100: make use of device clock
ARM: 8246/2: pcmcia: sa1111: provide device clock
ARM: 8245/1: pcmcia: soc-common: enable/disable socket clocks
ARM: 8244/1: fbdev: sa1100fb: make use of device clock
ARM: 8243/1: sa1100: add a clock alias for sa1111 pcmcia device
ARM: 8242/1: sa1100: add cpu clock
ARM: 8221/1: PJ4: allow building in Thumb-2 mode
ARM: 8234/1: sa1100: reorder IRQ handling code
ARM: 8233/1: sa1100: switch to hwirq usage
ARM: 8232/1: sa1100: merge GPIO multiplexer IRQ to "normal" irq domain
ARM: 8231/1: sa1100: introduce irqdomains support
ARM: 8230/1: sa1100: shift IRQs by one
ARM: 8229/1: sa1100: replace irq numbers with names in irq driver
ARM: 8228/1: sa1100: drop entry-macro.S
ARM: 8227/1: sa1100: switch to MULTI_IRQ_HANDLER
ARM: 8241/1: Update processor_modes for hyp and monitor mode
ARM: 8240/1: MCPM: document mcpm_sync_init()
ARM: 8239/1: Introduce {set,clear}_pte_bit
ARM: 8238/1: mm: Refine set_memory_* functions
ARM: 8237/1: fix flush_pfn_alias
...
Add a simple getter pm_runtime_is_irq_safe() for querying whether runtime
PM IRQ safe was set or not.
Various bus drivers implementing runtime PM may use choose to suspend
differently based on IRQ safeness status of child driver (e.g. do not
unprepare the clock if IRQ safe is not set).
Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Acked-by: Rafael J. Wysocki <rjw@rjwysocki.net>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This patch fix spelling typos found in Documentation/power.
Signed-off-by: Masanari Iida <standby24x7@gmail.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
* pnp:
MAINTAINERS: Remove Bjorn Helgaas as PNP maintainer
PNP / resources: remove positive test on unsigned values
* powercap:
powercap / RAPL: add new CPU IDs
powercap / RAPL: further relax energy counter checks
* pm-runtime:
PM / runtime: Update documentation to reflect the current code flow
* pm-opp:
PM / OPP: discard duplicate OPPs
PM / OPP: Make OPP invisible to users in Kconfig
PM / OPP: fix incorrect OPP count handling in of_init_opp_table
Update the device PM documentation in devices.txt and runtime_pm.txt
to reflect the changes in the system suspend and resume handling
related to the introduction of the new power.direct_complete flag.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
The runtime PM documentation in runtime_pm.txt has not been updated
after some changes to the system suspend and resume core code, so
update it to reflect the current code flow.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
The example uses foo_process_next_request() everywhere else.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Update the documentation for the removal of GENERIC_SUBSYS_PM_OPS in commit
90363ddf0a ("PM: Drop generic_subsys_pm_ops")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
As of commit 05aa55dddb ("PM / Runtime:
Lenient generic runtime pm callbacks"), the generic power management
callbacks pm_generic_runtime_suspend() and pm_generic_runtime_resume()
return 0, not -EINVAL, if the device doesn't provide its own callbacks.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
dev_pm_info.runtime_error has always been a signed int, to store a signed
error code. Correct the documentation.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
PM core and driver core has changed some behavior regarding use of
runtime PM. Update the documentation accordingly.
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
For devices which don't have a .runtime_idle() callback or if it
returns 0, rpm_idle() will end up in triggering a call to
rpm_suspend(), thus trying to carry out a runtime suspend directly
from runtime_idle().
In the above situation we want to respect devices which has enabled
autosuspend, we therfore append the flag sent to rpm_suspend with
RPM_AUTO.
Do note that drivers still needs to update the device last busy mark,
to control the delay for this circumstance.
Updated runtime PM documentation accordingly.
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Acked-by: Kevin Hilman <khilman@linaro.org>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Runtime PM documentation needs to be updated after the previous
change of the rpm_idle() behavior, so modify it as appropriate.
[rjw: Subject and changelog]
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
The "runtime idle" helper routine, rpm_idle(), currently ignores
return values from .runtime_idle() callbacks executed by it.
However, it turns out that many subsystems use
pm_generic_runtime_idle() which checks the return value of the
driver's callback and executes pm_runtime_suspend() for the device
unless that value is not 0. If that logic is moved to rpm_idle()
instead, pm_generic_runtime_idle() can be dropped and its users
will not need any .runtime_idle() callbacks any more.
Moreover, the PCI, SCSI, and SATA subsystems' .runtime_idle()
routines, pci_pm_runtime_idle(), scsi_runtime_idle(), and
ata_port_runtime_idle(), respectively, as well as a few drivers'
ones may be simplified if rpm_idle() calls rpm_suspend() after 0 has
been returned by the .runtime_idle() callback executed by it.
To reduce overall code bloat, make the changes described above.
Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Tested-by: Kevin Hilman <khilman@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Kevin Hilman <khilman@linaro.org>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
This boolean function simply returns whether or not the runtime
status of the device is 'active'. The typical scenario is driver
calls pm_runtime_get firstly, then check pm_runtime_active in
atomic environment.
Also add entry to Documentation/power/runtime.txt
Signed-off-by: Yanmin Zhang <yanmin.zhang@intel.com>
Signed-off-by: ShuoX Liu <shuox.liu@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Currently, the PM core disables runtime PM for all devices right
after executing subsystem/driver .suspend() callbacks for them
and re-enables it right before executing subsystem/driver .resume()
callbacks for them. This may lead to problems when there are
two devices such that the .suspend() callback executed for one of
them depends on runtime PM working for the other. In that case,
if runtime PM has already been disabled for the second device,
the first one's .suspend() won't work correctly (and analogously
for resume).
To make those issues go away, make the PM core disable runtime PM
for devices right before executing subsystem/driver .suspend_late()
callbacks for them and enable runtime PM for them right after
executing subsystem/driver .resume_early() callbacks for them. This
way the potential conflitcs between .suspend_late()/.resume_early()
and their runtime PM counterparts are still prevented from happening,
but the subtle ordering issues related to disabling/enabling runtime
PM for devices during system suspend/resume are much easier to avoid.
Reported-and-tested-by: Jan-Matthias Braun <jan_braun@gmx.net>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Reviewed-by: Kevin Hilman <khilman@deeprootsystems.com>
Cc: 3.4+ <stable@vger.kernel.org>
Make the PM core execute driver PM callbacks directly if the
corresponding subsystem callbacks are not present.
There are three reasons for doing that. First, it reflects the
behavior of drivers/base/dd.c:really_probe() that runs the driver's
.probe() callback directly if the bus type's one is not defined, so
this change will remove one arbitrary difference between the PM core
and the remaining parts of the driver core. Second, it will allow
some subsystems, whose PM callbacks don't do anything except for
executing driver callbacks, to be simplified quite a bit by removing
those "forward-only" callbacks. Finally, it will allow us to remove
one level of indirection in the system suspend and resume code paths
where it is not necessary, which is going to lead to less debug noise
with initcall_debug passed in the kernel command line (messages won't
be printed for driverless devices whose subsystems don't provide
PM callbacks among other things).
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
The runtime PM core code behavior related to the power.irq_safe
device flag has changed recently and the documentation should be
modified to reflect it.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
The current power management documentation in Documentation/power/
either doesn't cover PM domains at all, or gives inaccurate
information about them, so update the relevant files in there to
follow the code.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Originally, the runtime PM core would send an idle notification
whenever a suspend attempt failed. The idle callback routine could
then schedule a delayed suspend for some time later.
However this behavior was changed by commit
f71648d73c (PM / Runtime: Remove idle
notification after failing suspend). No notifications were sent, and
there was no clear mechanism to retry failed suspends.
This caused problems for the usbhid driver, because it fails
autosuspend attempts as long as a key is being held down. Therefore
this patch (as1492) adds a mechanism for retrying failed
autosuspends. If the callback routine updates the last_busy field so
that the next autosuspend expiration time is in the future, the
autosuspend will automatically be rescheduled.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Tested-by: Henrik Rydberg <rydberg@euromail.se>
Cc: <stable@kernel.org>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Support for device power domains has been introduced in
commit 9659cc0678 (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 <ming.lei@canonical.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
* 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
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 <tom.leiming@gmail.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
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 <rjw@sisk.pl>
Acked-by: Kevin Hilman <khilman@ti.com>
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 <ccross@android.com>
Reviewed-by: Kevin Hilman <khilman@ti.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
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 <ccross@google.com>
Tested-by: Nishanth Menon <nm@ti.com>
Signed-off-by: Kevin Hilman <khilman@ti.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
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 <khilman@ti.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
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 <rjw@sisk.pl>
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 <rjw@sisk.pl>
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 e866500247
(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 e866500247
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
e866500247 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 <rjw@sisk.pl>
Acked-by: Kevin Hilman <khilman@ti.com>
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 <rjw@sisk.pl>
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 <rjw@sisk.pl>
Reviewed-by: Kevin Hilman <khilman@ti.com>
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 <rjw@sisk.pl>
Commit e1866b33b1 (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 <rjw@sisk.pl>
Reviewed-by: Kevin Hilman <khilman@ti.com>
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 <khilman@ti.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Commit e866500247 (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 <khilman@ti.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
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 <rjw@sisk.pl>
Acked-by: Kevin Hilman <khilman@ti.com>
Reasoning-sounds-sane-to: Grant Likely <grant.likely@secretlab.ca>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
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 <stern@rowland.harvard.edu>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
There are some situations (e.g. in __pm_generic_call()), where
pm_runtime_suspended() is used to decide whether or not to execute
a device's (system) ->suspend() callback. The callback is not
executed if pm_runtime_suspended() returns true, but it does so
for devices that don't even support runtime PM, because the
power.disable_depth device field is ignored by it. This leads to
problems (i.e. devices are not suspened when they should), so rework
pm_runtime_suspended() so that it returns false if the device's
power.disable_depth field is different from zero.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Cc: stable@kernel.org
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>
