Move the trace_device_pm_callback locations for dpm_prepare and dpm_complete
to encompass the attempt to capture the device mutex prior to callback. This
is needed by analyze_suspend to identify gaps in the trace output caused by
the delay in locking the mutex for a device.
Signed-off-by: NTodd Brandt <todd.e.brandt@linux.intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Occasionally, the system can't come back up after suspend/resume
due to problems of device suspending phase. This patch make
PM_TRACE infrastructure cover device suspending phase of
suspend/resume process, and the information in RTC can tell
developers which device suspending function make system hang.
Signed-off-by: NZhonghui Fu <zhonghui.fu@linux.intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

If an asynchronous suspend_late or freeze_late callback fails
during the SUSPEND, FREEZE or QUIESCE phases, we don't propagate the
corresponding error correctly, in effect ignoring the error and
continuing the suspend-to-ram/hibernation. During suspend-to-ram this
could leave some devices without a valid saved context, leading to a
failure to reinitialize them during resume. During hibernation this
could leave some devices active interfeering with the creation /
restoration of the hibernation image. Also this could leave the
corresponding devices without a valid saved context and failure to
reinitialize them during resume.

Fixes: de377b39 (PM / sleep: Asynchronous threads for suspend_late)
Signed-off-by: NImre Deak <imre.deak@intel.com>
Cc: 3.15+ <stable@vger.kernel.org> # 3.15+
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Subsequent change sets will add platform-related operations between
dpm_suspend_late() and dpm_suspend_noirq() as well as between
dpm_resume_noirq() and dpm_resume_early() in suspend_enter(), so
export these functions for suspend_enter() to be able to call them
separately and split the invocations of dpm_suspend_end() and
dpm_resume_start() in there accordingly.
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Fix kernel-doc warnings in drivers/base/power/main.c:

Warning(..//drivers/base/power/main.c:473): No description found for parameter 'async'
Warning(..//drivers/base/power/main.c:601): No description found for parameter 'async'
Warning(..//drivers/base/power/main.c:1012): No description found for parameter 'async'
Warning(..//drivers/base/power/main.c:1151): No description found for parameter 'async'
Warning(..//drivers/base/power/main.c:1305): No description found for parameter 'info'
Signed-off-by: NRandy Dunlap <rdunlap@infradead.org>
Acked-by: NPavel Machek <pavel@ucw.cz>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Adds two trace events which supply the same info that initcall_debug
provides, but via ftrace instead of dmesg. The existing initcall_debug
calls require the pm_print_times_enabled var to be set (either via
sysfs or via the kernel cmd line). The new trace events provide all the
same info as the initcall_debug prints but with less overhead, and also
with coverage of device prepare and complete device callbacks.

These events replace the device_pm_report_time event (which has been
removed). device_pm_callback_start is called first and provides the device
and callback info. device_pm_callback_end is called after with the
device name and error info. The time and pid are gathered from the trace
data headers.
Signed-off-by: NTodd Brandt <todd.e.brandt@intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Adds trace events that give finer resolution into suspend/resume. These
events are graphed in the timelines generated by the analyze_suspend.py
script. They represent large areas of time consumed that are typical to
suspend and resume.

The event is triggered by calling the function "trace_suspend_resume"
with three arguments: a string (the name of the event to be displayed
in the timeline), an integer (case specific number, such as the power
state or cpu number), and a boolean (where true is used to denote the start
of the timeline event, and false to denote the end).

The suspend_resume trace event reproduces the data that the machine_suspend
trace event did, so the latter has been removed.
Signed-off-by: NTodd Brandt <todd.e.brandt@intel.com>
Acked-by: NSteven Rostedt <rostedt@goodmis.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Currently, some subsystems (e.g. PCI and the ACPI PM domain) have to
resume all runtime-suspended devices during system suspend, mostly
because those devices may need to be reprogrammed due to different
wakeup settings for system sleep and for runtime PM.

For some devices, though, it's OK to remain in runtime suspend
throughout a complete system suspend/resume cycle (if the device was in
runtime suspend at the start of the cycle).  We would like to do this
whenever possible, to avoid the overhead of extra power-up and power-down
events.

However, problems may arise because the device's descendants may require
it to be at full power at various points during the cycle.  Therefore the
most straightforward way to do this safely is if the device and all its
descendants can remain runtime suspended until the complete stage of
system resume.

To this end, introduce a new device PM flag, power.direct_complete
and modify the PM core to use that flag as follows.

If the ->prepare() callback of a device returns a positive number,
the PM core will regard that as an indication that it may leave the
device runtime-suspended.  It will then check if the system power
transition in progress is a suspend (and not hibernation in particular)
and if the device is, indeed, runtime-suspended.  In that case, the PM
core will set the device's power.direct_complete flag.  Otherwise it
will clear power.direct_complete for the device and it also will later
clear it for the device's parent (if there's one).

Next, the PM core will not invoke the ->suspend() ->suspend_late(),
->suspend_irq(), ->resume_irq(), ->resume_early(), or ->resume()
callbacks for all devices having power.direct_complete set.  It
will invoke their ->complete() callbacks, however, and those
callbacks are then responsible for resuming the devices as
appropriate, if necessary.  For example, in some cases they may
need to queue up runtime resume requests for the devices using
pm_request_resume().

Changelog partly based on an Alan Stern's description of the idea
(http://marc.info/?l=linux-pm&m=139940466625569&w=2).
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: NAlan Stern <stern@rowland.harvard.edu>

This patch adds cpufreq suspend/resume calls to dpm_{suspend|resume}()
for handling suspend/resume of cpufreq governors.

Lan Tianyu (Intel) & Jinhyuk Choi (Broadcom) found an issue where the
tunables configuration for clusters/sockets with non-boot CPUs was
lost after system suspend/resume, as we were notifying governors with
CPUFREQ_GOV_POLICY_EXIT on removal of the last CPU for that policy
which caused the tunables memory to be freed.

This is fixed by preventing any governor operations from being
carried out between the device suspend and device resume stages of
system suspend and resume, respectively.

We could have added these callbacks at dpm_{suspend|resume}_noirq()
level, but there is an additional problem that the majority of I/O
devices is already suspended at that point and if cpufreq drivers
want to change the frequency before suspending, then that not be
possible on some platforms (which depend on peripherals like i2c,
regulators, etc).
Reported-and-tested-by: NLan Tianyu <tianyu.lan@intel.com>
Reported-by: NJinhyuk Choi <jinchoi@broadcom.com>
Signed-off-by: NViresh Kumar <viresh.kumar@linaro.org>
[rjw: Changelog]
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

In analogy with commits 5af84b82 and 97df8c12, using
asynchronous threads can improve the overall suspend_late
time significantly.

This patch is for suspend_late phase.
Signed-off-by: NChuansheng Liu <chuansheng.liu@intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

In analogy with commits 5af84b82 and 97df8c12, using
asynchronous threads can improve the overall suspend_noirq
time significantly.

This patch is for suspend_noirq phase.
Signed-off-by: NChuansheng Liu <chuansheng.liu@intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

In analogy with commits 5af84b82 and 97df8c12, using
asynchronous threads can improve the overall resume_early
time significantly.

This patch is for resume_early phase.
Signed-off-by: NChuansheng Liu <chuansheng.liu@intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

In analogy with commits 5af84b82 and 97df8c12, using
asynchronous threads can improve the overall resume_noirq time
significantly.

One typical case is:
In resume_noirq phase and for the PCI devices, the function
pci_pm_resume_noirq() will be called, and there is one d3_delay
(10ms) at least.

With the way of asynchronous threads, we just need wait d3_delay
time once in parallel for each calling, which saves much time to
resume quickly.
Signed-off-by: NChuansheng Liu <chuansheng.liu@intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

The patch is a helper adding two new flags for implementing
async threads for suspend_noirq and suspend_late.
Signed-off-by: NChuansheng Liu <chuansheng.liu@intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Commit 5a87182a (cpufreq: suspend governors on system
suspend/hibernate) causes hibernation problems to happen on
Bjørn Mork's and Paul Bolle's systems, so revert it.

Fixes: 5a87182a (cpufreq: suspend governors on system suspend/hibernate)
Reported-by: NBjørn Mork <bjorn@mork.no>
Reported-by: NPaul Bolle <pebolle@tiscali.nl>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

This patch adds cpufreq suspend/resume calls to dpm_{suspend|resume}_noirq()
for handling suspend/resume of cpufreq governors.

Lan Tianyu (Intel) & Jinhyuk Choi (Broadcom) found anr issue where
tunables configuration for clusters/sockets with non-boot CPUs was
getting lost after suspend/resume, as we were notifying governors
with CPUFREQ_GOV_POLICY_EXIT on removal of the last cpu for that
policy and so deallocating memory for tunables. This is fixed by
this patch as we don't allow any operation on governors after
device suspend and before device resume now.
Reported-and-tested-by: NLan Tianyu <tianyu.lan@intel.com>
Reported-by: NJinhyuk Choi <jinchoi@broadcom.com>
Signed-off-by: NViresh Kumar <viresh.kumar@linaro.org>
[rjw: Changelog, minor cleanups]
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Use this new function to make code more comprehensible, since we are
reinitialzing the completion, not initializing.

[akpm@linux-foundation.org: linux-next resyncs]
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>
Acked-by: Linus Walleij <linus.walleij@linaro.org> (personally at LCE13)
Cc: Ingo Molnar <mingo@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

If a device prepare callback for some reason would fail, the PM core
prevented the device from going inactive forever.

In this case, to reverse the pm_runtime_get_noresume() we invokes the
asyncronous pm_runtime_put(), thus restoring the usage count.
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Rather than hard-lock the kernel, dump the suspend/resume thread stack
and panic() to capture a message in pstore when a driver takes too long
to suspend/resume. Default suspend/resume watchdog timeout is set to 12
seconds to be longer than the usbhid 10 second timeout, but could be
changed at compile time.

Exclude from the watchdog the time spent waiting for children that
are resumed asynchronously and time every device, whether or not they
resumed synchronously.

This patch is targeted for mobile devices where a suspend/resume lockup
could cause a system reboot. Information about failing device can be
retrieved in subsequent boot session by mounting pstore and inspecting
the log. Laptops with EFI-enabled pstore could also benefit from
this feature.

The hardware watchdog timer is likely suspended during this time and
couldn't be relied upon. The soft-lockup detector would eventually tell
that tasks are not scheduled, but would provide little context as to why.
The patch hence uses system timer and assumes it is still active while the
devices are suspended/resumed.

This feature can be enabled/disabled during kernel configuration.

This change is based on earlier work by San Mehat.
Signed-off-by: NBenoit Goby <benoit@android.com>
Signed-off-by: NZoran Markovic <zoran.markovic@linaro.org>
Acked-by: NUlf Hansson <ulf.hansson@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

A new trace event is added to PM events to print the time it takes to
suspend and resume a device.  It generates trace messages that
include device, driver, parent information in addition to the type of
PM ops invoked as well as the PM event and error status from the PM
ops. Example trace below:

bash-2239  [000] ....   290.883035: device_pm_report_time: backlight
 acpi_video0 parent=0000:00:02.0 state=freeze ops=class nsecs=332 err=0
bash-2239  [000] ....   290.883041: device_pm_report_time: rfkill rf
kill3 parent=phy0 state=freeze ops=legacy class nsecs=216 err=0
bash-2239  [001] ....   290.973892: device_pm_report_time: ieee80211
 phy0 parent=0000:01:00.0 state=freeze ops=legacy class nsecs=90846477 err=0

bash-2239  [001] ....   293.660129: device_pm_report_time: ieee80211 phy0 parent=0000:01:00.0 state=restore ops=legacy class nsecs=101295162 err=0
bash-2239  [001] ....   293.660147: device_pm_report_time: rfkill rfkill3 parent=phy0 state=restore ops=legacy class nsecs=1804 err=0
bash-2239  [001] ....   293.660157: device_pm_report_time: backlight acpi_video0 parent=0000:00:02.0 state=restore ops=class nsecs=757 err=0
Signed-off-by: NShuah Khan <shuah.kh@samsung.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Use the asyncronous runtime PM API when returning the runtime
reference for the device after the system resume is completed.

By using the asyncronous runtime PM API we don't have to wait
for each an every device to become idle|suspended. Instead we
can move on and handle the next device in queue.
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Device PM QoS sysfs attributes, if present during device removal,
are removed from within device_pm_remove(), which is too late,
since dpm_sysfs_remove() has already removed the whole attribute
group they belonged to.  However, moving the removal of those
attributes to dpm_sysfs_remove() alone is not sufficient, because
in theory they still can be re-added right after being removed by it
(the device's driver is still bound to it at that point).

For this reason, move the entire desctruction of device PM QoS
constraints to dpm_sysfs_remove() and make it prevent any new
constraints from being added after it has run.  Also, move the
initialization of the power.qos field in struct device to
device_pm_init_common() and drop the no longer needed
dev_pm_qos_constraints_init().
Reported-by: NSasha Levin <sasha.levin@oracle.com>
Signed-off-by: NRafael 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: NJan-Matthias Braun <jan_braun@gmx.net>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: NUlf Hansson <ulf.hansson@linaro.org>
Reviewed-by: NKevin Hilman <khilman@deeprootsystems.com>
Cc: 3.4+ <stable@vger.kernel.org>

This patch (as1591) moves the pm_runtime_get_noresume() and
pm_runtime_put_sync() calls from __device_suspend() and
device_resume() to device_prepare() and device_complete() in the PM
core.

The reason for doing this is to make sure that parent devices remain
at full power (i.e., don't go into runtime suspend) while their
children are being resumed from a system sleep.

The PCI core already contained equivalent code to serve the same
purpose.  The patch removes the duplicated code, since it is no longer
needed.  One of the comments from the PCI core gets moved into the PM
core, and a second comment is added to explain whe the _get_noresume
and _put_sync calls are present.
Signed-off-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>

When dpm_suspend_noirq fail, state is PMSG_SUSPEND,
should change to PMSG_RESUME when dpm_resume_early is called
Signed-off-by: NFeng Hong <hongfeng@marvell.com>
Signed-off-by: NRaul Xiong <xjian@marvell.com>
Signed-off-by: NNeil Zhang <zhangwm@marvell.com>
Cc: stable@vger.kernel.org
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>

The syscore device PM flag is used to mark the devices (belonging to
a PM domain) that should never be turned off, except for the system
core (syscore) suspend/hibernation and resume stages.  That flag is
stored in the device's struct pm_subsys_data object whose address is
available from struct device.  However, in some situations it may be
convenient to set that flag before the device is added to a PM
domain, so it is better to move it directly to the "power" member of
struct device.  Then, it can be checked by the routines in
drivers/base/power/runtime.c and drivers/base/power/main.c, which is
more straightforward.

This also reduces the number of dev_gpd_data() invocations in the
generic PM domains framework, so the overhead related to the syscore
flag is slightly smaller.
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>
Acked-by: NMagnus Damm <damm@opensource.se>

Make the device power management initialization more straightforward
by moving the initialization of common (i.e. used by both runtime PM
and system suspend) fields to a separate routine.
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>

dpm_list and its pm lock provide a good way to iterate all
devices in system. Except this way, there is no other easy
way to iterate devices in system.

firmware loader need to cache firmware images for devices
before system sleep, so introduce the function to meet its
demand.
Reported-by: NFengguang Wu <fengguang.wu@intel.com>
Signed-off-by: NMing Lei <ming.lei@canonical.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Commit cf579dfb (PM / Sleep: Introduce
"late suspend" and "early resume" of devices) introduced a bug where
suspend_late handlers would be called, but if dpm_suspend_noirq returned
an error the early_resume handlers would never be called.  All devices
would end up on the dpm_late_early_list, and would never be resumed
again.

Fix it by calling dpm_resume_early when dpm_suspend_noirq returns
an error.
Signed-off-by: NColin Cross <ccross@android.com>
Cc: stable@vger.kernel.org
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>

Fix the following sparse warnings:
drivers/base/power/main.c:48:1: warning: symbol 'dpm_prepared_list' was not declared. Should it be static?
drivers/base/power/main.c:49:1: warning: symbol 'dpm_suspended_list' was not declared. Should it be static?
drivers/base/power/main.c:50:1: warning: symbol 'dpm_late_early_list' was not declared. Should it be static?
drivers/base/power/main.c:51:1: warning: symbol 'dpm_noirq_list' was not declared. Should it be static?
Signed-off-by: NSachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>

On certain bios, resume hangs if cpus are allowed to enter idle states
during suspend [1].

This was fixed in apci idle driver [2].But intel_idle driver does not
have this fix. Thus instead of replicating the fix in both the idle
drivers, or in more platform specific idle drivers if needed, the
more general cpuidle infrastructure could handle this.

A suspend callback in cpuidle_driver could handle this fix. But
a cpuidle_driver provides only basic functionalities like platform idle
state detection capability and mechanisms to support entry and exit
into CPU idle states. All other cpuidle functions are found in the
cpuidle generic infrastructure for good reason that all cpuidle
drivers, irrepective of their platforms will support these functions.

One option therefore would be to register a suspend callback in cpuidle
which handles this fix. This could be called through a PM_SUSPEND_PREPARE
notifier. But this is too generic a notfier for a driver to handle.

Also, ideally the job of cpuidle is not to handle side effects of suspend.
It should expose the interfaces which "handle cpuidle 'during' suspend"
or any other operation, which the subsystems call during that respective
operation.

The fix demands that during suspend, no cpus should be allowed to enter
deep C-states. The interface cpuidle_uninstall_idle_handler() in cpuidle
ensures that. Not just that it also kicks all the cpus which are already
in idle out of their idle states which was being done during cpu hotplug
through a CPU_DYING_FROZEN callbacks.

Now the question arises about when during suspend should
cpuidle_uninstall_idle_handler() be called. Since we are dealing with
drivers it seems best to call this function during dpm_suspend().
Delaying the call till dpm_suspend_noirq() does no harm, as long as it is
before cpu_hotplug_begin() to avoid race conditions with cpu hotpulg
operations. In dpm_suspend_noirq(), it would be wise to place this call
before suspend_device_irqs() to avoid ugly interactions with the same.

Ananlogously, during resume.

References:
[1] https://bugs.launchpad.net/ubuntu/+source/linux/+bug/674075.
[2] http://marc.info/?l=linux-pm&m=133958534231884&w=2Reported-and-tested-by: NDave Hansen <dave@linux.vnet.ibm.com>
Signed-off-by: NPreeti U Murthy <preeti@linux.vnet.ibm.com>
Reviewed-by: NSrivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>

Change the behavior of the newly introduced
/sys/power/pm_print_times attribute so that its initial value
depends on initcall_debug, but setting it to 0 will cause device
suspend/resume times not to be printed, even if initcall_debug has
been set.  This way, the people who use initcall_debug for reasons
other than PM debugging will be able to switch the suspend/resume
times printing off, if need be.
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>
Reviewed-by: NSrivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Acked-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Added a new knob called /sys/power/pm_print_times. Setting it to 1
enables printing of time taken by devices to suspend and resume.
Setting it to 0 disables this printing (unless overridden by
initcall_debug kernel command line option).
Signed-off-by: NSameer Nanda <snanda@chromium.org>
Acked-by: NGreg KH <gregkh@linuxfoundation.org>
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>

__device_suspend() must always send a completion. Otherwise, parent
devices will wait forever.

Commit 1e2ef05b, "PM: Limit race conditions between runtime PM and
system sleep (v2)", introduced a regression by short-circuiting the
complete_all() for certain error cases.

This patch fixes the bug by always signalling a completion.

Addresses http://crosbug.com/31972

Tested by injecting an abort.
Signed-off-by: NMandeep Singh Baines <msb@chromium.org>
Cc: stable@vger.kernel.org
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>

Currently, the device suspend code in drivers/base/power/main.c
only checks if there have been any wakeup events, and therefore the
ongoing system transition to a sleep state should be aborted, during
the first (i.e. "suspend") device suspend phase.  However, wakeup
events may be reported later as well, so it's reasonable to look for
them in the in the subsequent (i.e. "late suspend" and "suspend
noirq") phases.
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>
Acked-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The current device suspend/resume phases during system-wide power
transitions appear to be insufficient for some platforms that want
to use the same callback routines for saving device states and
related operations during runtime suspend/resume as well as during
system suspend/resume.  In principle, they could point their
.suspend_noirq() and .resume_noirq() to the same callback routines
as their .runtime_suspend() and .runtime_resume(), respectively,
but at least some of them require device interrupts to be enabled
while the code in those routines is running.

It also makes sense to have device suspend-resume callbacks that will
be executed with runtime PM disabled and with device interrupts
enabled in case someone needs to run some special code in that
context during system-wide power transitions.

Apart from this, .suspend_noirq() and .resume_noirq() were introduced
as a workaround for drivers using shared interrupts and failing to
prevent their interrupt handlers from accessing suspended hardware.
It appears to be better not to use them for other porposes, or we may
have to deal with some serious confusion (which seems to be happening
already).

For the above reasons, introduce new device suspend/resume phases,
"late suspend" and "early resume" (and analogously for hibernation)
whose callback will be executed with runtime PM disabled and with
device interrupts enabled and whose callback pointers generally may
point to runtime suspend/resume routines.
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>
Reviewed-by: NMark Brown <broonie@opensource.wolfsonmicro.com>
Reviewed-by: NKevin Hilman <khilman@ti.com>

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: NRafael J. Wysocki <rjw@sisk.pl>

Make the pm_op() and pm_noirq_op() functions return pointers to
appropriate callbacks instead of executing those callbacks and
returning their results.

This change is required for a subsequent modification that will
execute the corresponding driver callback if the subsystem
callback returned by either pm_op(), or pm_noirq_op() is NULL.
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>

Make pm_op() and pm_noirq_op() use the same helper function for
running callbacks, which will cause them to use the same format of
diagnostic messages.  This also reduces the complexity and size of
the code quite a bit.
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>
Acked-by: NGreg Kroah-Hartman <gregkh@suse.de>

Remove a few if () and return statements in device_suspend_noirq()
that aren't really necessary.
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>
Reviewed-by: NSrivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>