Commit graph

55 commits

Author SHA1 Message Date
Rafael J. Wysocki
a436b6a19f PM / runtime: Add new helper for conditional usage count incrementation
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>
2015-12-21 03:11:12 +01:00
Alan Stern
019d8817b1 PM / sleep: Allow devices without runtime PM to do direct-complete
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>
2015-07-21 23:14:22 +02:00
Ben Dooks
f6a2fbb903 PM / runtime: add note about re-calling in during device probe()
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>
2015-05-13 00:02:38 +02:00
Linus Torvalds
26ceb127f7 Merge branch 'for-linus' of git://ftp.arm.linux.org.uk/~rmk/linux-arm
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
  ...
2014-12-12 15:26:48 -08:00
Krzysztof Kozlowski
3fb1581ea1 ARM: 8199/1: PM / Runtime: Add getter for querying the IRQ safe option v12
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>
2014-11-17 20:23:34 +00:00
Masanari Iida
1f999d14fc Documentation: power: Fix typo in Documentation/power
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>
2014-11-08 09:15:14 -05:00
Rafael J. Wysocki
cd0c5bd391 Merge branches 'pnp', 'powercap', 'pm-runtime' and 'pm-opp'
* 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
2014-06-03 23:13:00 +02:00
Rafael J. Wysocki
f71495f3f0 PM / sleep: Update device PM documentation to cover direct_complete
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>
2014-05-16 23:15:44 +02:00
Rafael J. Wysocki
4ec6a9cc23 PM / runtime: Update documentation to reflect the current code flow
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>
2014-05-16 23:05:40 +02:00
Geert Uytterhoeven
fe98245073 PM / Runtime: s/foo_process_requests/foo_process_next_request/
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>
2014-03-26 16:33:06 +01:00
Geert Uytterhoeven
fd6fe82673 PM / Runtime: GENERIC_SUBSYS_PM_OPS is gone
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>
2014-03-26 16:33:06 +01:00
Geert Uytterhoeven
39c29f3dfc PM / Runtime: Correct documented return values for generic PM callbacks
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>
2014-03-26 16:33:05 +01:00
Geert Uytterhoeven
91e63cc035 PM / Runtime: Split line longer than 80 characters
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2014-03-26 16:33:05 +01:00
Geert Uytterhoeven
e1a2976011 PM / Runtime: dev_pm_info.runtime_error is signed
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>
2014-03-26 16:33:05 +01:00
Ulf Hansson
ea309944e2 PM / Runtime: Update documentation around probe|remove|suspend
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>
2013-11-12 23:20:30 +01:00
Ulf Hansson
d66e6db28d PM / Runtime: Respect autosuspend when idle triggers suspend
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>
2013-10-16 02:06:57 +02:00
Alan Stern
43d51af489 PM / Runtime: Update .runtime_idle() callback documentation
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>
2013-06-03 21:49:59 +02:00
Rafael J. Wysocki
45f0a85c82 PM / Runtime: Rework the "runtime idle" helper routine
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>
2013-06-03 21:49:52 +02:00
ShuoX Liu
fbadc58dd3 PM / Runtime: Add new helper function: pm_runtime_active()
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>
2013-01-26 00:39:12 +01:00
Rafael J. Wysocki
9f6d8f6ab2 PM: Move disabling/enabling runtime PM to late suspend/early resume
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>
2013-01-06 00:35:55 +01:00
Rafael J. Wysocki
35cd133c61 PM: Run the driver callback directly if the subsystem one is not there
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>
2011-12-21 22:01:05 +01:00
Rafael J. Wysocki
9075659219 PM / Runtime: Make documentation follow the new behavior of irq_safe
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>
2011-11-28 22:14:34 +01:00
Rafael J. Wysocki
5841eb6402 PM / Domains: Document how PM domains are used by the PM core
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>
2011-11-28 22:14:19 +01:00
Alan Stern
886486b792 PM / Runtime: Automatically retry failed autosuspends
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>
2011-11-04 22:28:14 +01:00
Rafael J. Wysocki
9bd717c0dc Merge branch 'pm-runtime' into pm-for-linus
* pm-runtime:
  PM / Runtime: Handle .runtime_suspend() failure correctly
  PM / Runtime: Fix kerneldoc comment for rpm_suspend()
  PM / Runtime: Update document about callbacks
2011-10-16 23:26:49 +02:00
Ming Lei
2fb242adca PM / Runtime: Update document about callbacks
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>
2011-10-10 23:37:23 +02:00
Rafael J. Wysocki
d727b60659 Merge branch 'pm-runtime' into pm-for-linus
* 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
2011-10-07 23:16:55 +02:00
Ming Lei
2e6ba515f5 PM / Runtime: pm_runtime_idle() can be called in atomic context
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>
2011-09-21 22:31:33 +02:00
Rafael J. Wysocki
64584eb9cd PM / Runtime: Correct documentation of pm_runtime_irq_safe()
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>
2011-08-25 15:31:05 +02:00
Colin Cross
311aab73d2 PM / Runtime: Add might_sleep() to runtime PM functions
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>
2011-08-14 13:35:52 +02:00
Kevin Hilman
02b26774af PM / Runtime: Allow _put_sync() from interrupts-disabled context
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>
2011-08-05 21:45:20 +02:00
Kevin Hilman
f3393b62f1 PM / Runtime: Add new helper function: pm_runtime_status_suspended()
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>
2011-07-12 11:17:09 +02:00
Rafael J. Wysocki
62052ab1d1 PM / Runtime: Replace "run-time" with "runtime" in documentation
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>
2011-07-06 10:52:13 +02:00
Rafael J. Wysocki
e358bad75f PM / Runtime: Improve documentation of enable, disable and barrier
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>
2011-07-06 10:52:06 +02:00
Rafael J. Wysocki
1e2ef05bb8 PM: Limit race conditions between runtime PM and system sleep (v2)
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>
2011-07-06 10:51:58 +02:00
Rafael J. Wysocki
632e270e01 PM / Runtime: Return special error code if runtime PM is disabled
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>
2011-07-02 14:30:10 +02:00
Rafael J. Wysocki
455716e9b1 PM / Runtime: Update documentation of interactions with system sleep
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>
2011-07-02 14:30:09 +02:00
Rafael J. Wysocki
e529192883 PM: Introduce generic "noirq" callback routines for subsystems (v2)
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>
2011-07-02 14:29:55 +02:00
Rafael J. Wysocki
f5da24dbed PM / Runtime: Update documentation regarding driver removal
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>
2011-07-02 14:27:11 +02:00
Kevin Hilman
5efb54cc3f PM: Documentation: fix typo: pm_runtime_idle_sync() doesn't exist.
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>
2011-07-02 14:27:03 +02:00
Kevin Hilman
129b656a0d PM / Runtime: Update doc: usage count no longer incremented across system PM
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>
2011-06-21 23:17:59 +02:00
Rafael J. Wysocki
9659cc0678 PM: Make system-wide PM and runtime PM treat subsystems consistently
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>
2011-03-15 00:43:17 +01:00
Alan Stern
c7b61de5b7 PM / Runtime: Add synchronous runtime interface for interrupt handlers (v3)
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>
2010-12-24 15:02:41 +01:00
Rafael J. Wysocki
f08f5a0add PM / Runtime: Fix pm_runtime_suspended()
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
2010-12-16 17:12:25 +01:00
Alan Stern
15bcb91d7e PM / Runtime: Implement autosuspend support
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>
2010-10-17 01:57:48 +02:00
Alan Stern
7490e44239 PM / Runtime: Add no_callbacks flag
Some devices, such as USB interfaces, cannot be power-managed
independently of their parents, i.e., they cannot be put in low power
while the parent remains at full power.  This patch (as1425) creates a
new "no_callbacks" flag, which tells the PM core not to invoke the
runtime-PM callback routines for the such devices but instead to
assume that the callbacks always succeed.  In addition, the
non-debugging runtime-PM sysfs attributes for the devices are removed,
since they are pretty much meaningless.

The advantage of this scheme comes not so much from avoiding the
callbacks themselves, but rather from the fact that without the need
for a process context in which to run the callbacks, more work can be
done in interrupt context.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2010-10-17 01:57:47 +02:00
Jiri Kosina
318ae2edc3 Merge branch 'for-next' into for-linus
Conflicts:
	Documentation/filesystems/proc.txt
	arch/arm/mach-u300/include/mach/debug-macro.S
	drivers/net/qlge/qlge_ethtool.c
	drivers/net/qlge/qlge_main.c
	drivers/net/typhoon.c
2010-03-08 16:55:37 +01:00
Rafael J. Wysocki
d690b2cd22 PM: Provide generic subsystem-level callbacks
There are subsystems whose power management callbacks only need to
invoke the callbacks provided by device drivers.  Still, their system
sleep PM callbacks should play well with the runtime PM callbacks,
so that devices suspended at run time can be left in that state for
a system sleep transition.

Provide a set of generic PM callbacks for such subsystems and
define convenience macros for populating dev_pm_ops structures.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2010-03-06 21:28:37 +01:00
Rafael J. Wysocki
87d1b3e60b PM / Runtime: Document power.runtime_auto and related functions
The power.runtime_auto device flag and the helper functions
pm_runtime_allow() and pm_runtime_forbid() used to modify it are a
part of the run-time power management framework and therefore they
should be described in Documentation/power/runtime_pm.txt.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2010-03-06 21:28:17 +01:00
Thadeu Lima de Souza Cascardo
de8164fb22 doc: fix leve -> level typo in pm-runtime doc
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@holoscopio.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2010-02-05 12:22:37 +01:00