Commit Graph

116 Commits

Author SHA1 Message Date
Rafael J. Wysocki
ab232ba570 Merge branches 'pm-sleep' and 'pm-runtime'
* pm-sleep:
  PM / sleep: trace_device_pm_callback coverage in dpm_prepare/complete
  PM / wakeup: add a dummy wakeup_source to record statistics
  PM / sleep: Make suspend-to-idle-specific code depend on CONFIG_SUSPEND
  PM / sleep: Return -EBUSY from suspend_enter() on wakeup detection
  PM / tick: Add tracepoints for suspend-to-idle diagnostics
  PM / sleep: Fix symbol name in a comment in kernel/power/main.c
  leds / PM: fix hibernation on arm when gpio-led used with CPU led trigger
  ARM: omap-device: use SET_NOIRQ_SYSTEM_SLEEP_PM_OPS
  bus: omap_l3_noc: add missed callbacks for suspend-to-disk
  PM / sleep: Add macro to define common noirq system PM callbacks
  PM / sleep: Refine diagnostic messages in enter_state()
  PM / wakeup: validate wakeup source before activating it.

* pm-runtime:
  PM / Runtime: Update last_busy in rpm_resume
  PM / runtime: add note about re-calling in during device probe()
2015-06-19 01:18:02 +02:00
Rafael J. Wysocki
7d51d97925 cpuidle: Do not use CPUIDLE_DRIVER_STATE_START in cpuidle.c
The CPUIDLE_DRIVER_STATE_START symbol is defined as 1 only if
CONFIG_ARCH_HAS_CPU_RELAX is set, otherwise it is defined as 0.
However, if CONFIG_ARCH_HAS_CPU_RELAX is set, the first (index 0)
entry in the cpuidle driver's table of states is overwritten with
the default "poll" entry by the core.  The "state" defined by the
"poll" entry doesn't provide ->enter_dead and ->enter_freeze
callbacks and its exit_latency is 0.

For this reason, it is not necessary to use CPUIDLE_DRIVER_STATE_START
in cpuidle_play_dead() (->enter_dead is NULL, so the "poll state"
will be skipped by the loop).

It also is arguably unuseful to return states with exit_latency
equal to 0 from find_deepest_state(), so the function can be modified
to start the loop from index 0 and the "poll state" will be skipped by
it as a result of the check against latency_req.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Preeti U Murthy <preeti@linux.vnet.ibm.com>
2015-05-30 02:15:21 +02:00
Rafael J. Wysocki
87e9b9f1d8 PM / sleep: Make suspend-to-idle-specific code depend on CONFIG_SUSPEND
Since idle_should_freeze() is defined to always return 'false'
for CONFIG_SUSPEND unset, all of the code depending on it in
cpuidle_idle_call() is not necessary in that case.

Make that code depend on CONFIG_SUSPEND too to avoid building it
when it is not going to be used.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
2015-05-19 02:44:24 +02:00
Rafael J. Wysocki
0d94039fab cpuidle: Select a different state on tick_broadcast_enter() failures
If tick_broadcast_enter() fails in cpuidle_enter_state(),
try to find another idle state to enter instead of invoking
default_idle_call() immediately and returning -EBUSY which
should increase the chances of saving some energy in those
cases.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Preeti U Murthy <preeti@linux.vnet.ibm.com>
Tested-by: Preeti U Murthy <preeti@linux.vnet.ibm.com>
Tested-by: Sudeep Holla <sudeep.holla@arm.com>
Acked-by: Kevin Hilman <khilman@linaro.org>
2015-05-14 21:37:52 +02:00
Rafael J. Wysocki
827a5aefc5 sched / idle: Call default_idle_call() from cpuidle_enter_state()
The check of the cpuidle_enter() return value against -EBUSY
made in call_cpuidle() will not be necessary any more if
cpuidle_enter_state() calls default_idle_call() directly when it
is about to return -EBUSY, so make that happen and eliminate the
check.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Preeti U Murthy <preeti@linux.vnet.ibm.com>
Tested-by: Preeti U Murthy <preeti@linux.vnet.ibm.com>
Tested-by: Sudeep Holla <sudeep.holla@arm.com>
Acked-by: Kevin Hilman <khilman@linaro.org>
2015-05-14 21:37:47 +02:00
Rafael J. Wysocki
faad384928 sched / idle: Call idle_set_state() from cpuidle_enter_state()
Introduce a wrapper function around idle_set_state() called
sched_idle_set_state() that will pass this_rq() to it as the
first argument and make cpuidle_enter_state() call the new
function before and after entering the target state.

At the same time, remove direct invocations of idle_set_state()
from call_cpuidle().

This will allow the invocation of default_idle_call() to be
moved from call_cpuidle() to cpuidle_enter_state() safely
and call_cpuidle() to be simplified a bit as a result.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Preeti U Murthy <preeti@linux.vnet.ibm.com>
Tested-by: Preeti U Murthy <preeti@linux.vnet.ibm.com>
Tested-by: Sudeep Holla <sudeep.holla@arm.com>
Acked-by: Kevin Hilman <khilman@linaro.org>
2015-05-14 21:35:10 +02:00
Rafael J. Wysocki
7312280bd2 cpuidle: Fix the kerneldoc comment for cpuidle_enter_state()
The kerneldoc comment for cpuidle_enter_state() doesn't match the
function's header any more, so fix it.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2015-05-09 21:50:32 +02:00
Rafael J. Wysocki
a802ea9645 cpuidle: Check the sign of index in cpuidle_reflect()
Avoid calling the governor's ->reflect method if the state index
passed to cpuidle_reflect() is negative.

This allows the analogous check to be dropped from menu_reflect(),
so do that too, and ensures that arbitrary error codes can be
passed to cpuidle_reflect() as the index with no adverse
consequences.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
2015-05-04 22:53:28 +02:00
Rafael J. Wysocki
df8d9eeadd cpuidle: Run tick_broadcast_exit() with disabled interrupts
Commit 335f49196f (sched/idle: Use explicit broadcast oneshot
control function) replaced clockevents_notify() invocations in
cpuidle_idle_call() with direct calls to tick_broadcast_enter()
and tick_broadcast_exit(), but it overlooked the fact that
interrupts were already enabled before calling the latter which
led to functional breakage on systems using idle states with the
CPUIDLE_FLAG_TIMER_STOP flag set.

Fix that by moving the invocations of tick_broadcast_enter()
and tick_broadcast_exit() down into cpuidle_enter_state() where
interrupts are still disabled when tick_broadcast_exit() is
called.  Also ensure that interrupts will be disabled before
running tick_broadcast_exit() even if they have been enabled by
the idle state's ->enter callback.  Trigger a WARN_ON_ONCE() in
that case, as we generally don't want that to happen for states
with CPUIDLE_FLAG_TIMER_STOP set.

Fixes: 335f49196f (sched/idle: Use explicit broadcast oneshot control function)
Reported-and-tested-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Reported-and-tested-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2015-04-29 15:19:21 +02:00
Bartlomiej Zolnierkiewicz
d75e4af14e cpuidle: remove state_count field from struct cpuidle_device
Thomas Schlichter reports the following issue on his Samsung NC20:

"The C-states C1 and C2 to the OS when connected to AC, and additionally
 provides the C3 C-state when disconnected from AC.  However, the number
 of C-states shown in sysfs is fixed to the number of C-states present
 at boot.
   If I boot with AC connected, I always only see the C-states up to C2
   even if I disconnect AC.

   The reason is commit 130a5f6924 (ACPI / cpuidle: remove dev->state_count
   setting).  It removes the update of dev->state_count, but sysfs uses
   exactly this variable to show the C-states.

   The fix is to use drv->state_count in sysfs.  As this is currently the
   last user of dev->state_count, this variable can be completely removed."

Remove dev->state_count as per the above.

Reported-by: Thomas Schlichter <thomas.schlichter@web.de>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: 3.14+ <stable@vger.kernel.org> # 3.14+
[ rjw: Changelog ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2015-04-03 13:15:50 +02:00
Rafael J. Wysocki
ef2b22ac54 cpuidle / sleep: Use broadcast timer for states that stop local timer
Commit 3810631332 (PM / sleep: Re-implement suspend-to-idle handling)
overlooked the fact that entering some sufficiently deep idle states
by CPUs may cause their local timers to stop and in those cases it
is necessary to switch over to a broadcast timer prior to entering
the idle state.  If the cpuidle driver in use does not provide
the new ->enter_freeze callback for any of the idle states, that
problem affects suspend-to-idle too, but it is not taken into account
after the changes made by commit 3810631332.

Fix that by changing the definition of cpuidle_enter_freeze() and
re-arranging of the code in cpuidle_idle_call(), so the former does
not call cpuidle_enter() any more and the fallback case is handled
by cpuidle_idle_call() directly.

Fixes: 3810631332 (PM / sleep: Re-implement suspend-to-idle handling)
Reported-and-tested-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
2015-03-05 23:13:19 +01:00
Rafael J. Wysocki
31a3409065 cpuidle / sleep: Do sanity checks in cpuidle_enter_freeze() too
Modify cpuidle_enter_freeze() to do the sanity checks done by
cpuidle_select() to avoid crashing the suspend-to-idle code
path in case something is missing.

Fixes: 3810631332 (PM / sleep: Re-implement suspend-to-idle handling)
Original-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
2015-02-28 23:46:39 +01:00
Rafael J. Wysocki
01e04f466e idle / sleep: Avoid excessive disabling and enabling interrupts
Disabling interrupts at the end of cpuidle_enter_freeze() is not
useful, because its caller, cpuidle_idle_call(), re-enables them
right away after invoking it.

To avoid that unnecessary back and forth dance with interrupts,
make cpuidle_enter_freeze() enable interrupts after calling
enter_freeze_proper() and drop the local_irq_disable() at its
end, so that all of the code paths in it end up with interrupts
enabled.  Then, cpuidle_idle_call() will not need to re-enable
interrupts after calling cpuidle_enter_freeze() any more, because
the latter will return with interrupts enabled, in analogy with
cpuidle_enter().

Reported-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
2015-02-28 23:46:24 +01:00
Rafael J. Wysocki
124cf9117c PM / sleep: Make it possible to quiesce timers during suspend-to-idle
The efficiency of suspend-to-idle depends on being able to keep CPUs
in the deepest available idle states for as much time as possible.
Ideally, they should only be brought out of idle by system wakeup
interrupts.

However, timer interrupts occurring periodically prevent that from
happening and it is not practical to chase all of the "misbehaving"
timers in a whack-a-mole fashion.  A much more effective approach is
to suspend the local ticks for all CPUs and the entire timekeeping
along the lines of what is done during full suspend, which also
helps to keep suspend-to-idle and full suspend reasonably similar.

The idea is to suspend the local tick on each CPU executing
cpuidle_enter_freeze() and to make the last of them suspend the
entire timekeeping.  That should prevent timer interrupts from
triggering until an IO interrupt wakes up one of the CPUs.  It
needs to be done with interrupts disabled on all of the CPUs,
though, because otherwise the suspended clocksource might be
accessed by an interrupt handler which might lead to fatal
consequences.

Unfortunately, the existing ->enter callbacks provided by cpuidle
drivers generally cannot be used for implementing that, because some
of them re-enable interrupts temporarily and some idle entry methods
cause interrupts to be re-enabled automatically on exit.  Also some
of these callbacks manipulate local clock event devices of the CPUs
which really shouldn't be done after suspending their ticks.

To overcome that difficulty, introduce a new cpuidle state callback,
->enter_freeze, that will be guaranteed (1) to keep interrupts
disabled all the time (and return with interrupts disabled) and (2)
not to touch the CPU timer devices.  Modify cpuidle_enter_freeze() to
look for the deepest available idle state with ->enter_freeze present
and to make the CPU execute that callback with suspended tick (and the
last of the online CPUs to execute it with suspended timekeeping).

Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
2015-02-15 19:40:09 +01:00
Rafael J. Wysocki
3810631332 PM / sleep: Re-implement suspend-to-idle handling
In preparation for adding support for quiescing timers in the final
stage of suspend-to-idle transitions, rework the freeze_enter()
function making the system wait on a wakeup event, the freeze_wake()
function terminating the suspend-to-idle loop and the mechanism by
which deep idle states are entered during suspend-to-idle.

First of all, introduce a simple state machine for suspend-to-idle
and make the code in question use it.

Second, prevent freeze_enter() from losing wakeup events due to race
conditions and ensure that the number of online CPUs won't change
while it is being executed.  In addition to that, make it force
all of the CPUs re-enter the idle loop in case they are in idle
states already (so they can enter deeper idle states if possible).

Next, drop cpuidle_use_deepest_state() and replace use_deepest_state
checks in cpuidle_select() and cpuidle_reflect() with a single
suspend-to-idle state check in cpuidle_idle_call().

Finally, introduce cpuidle_enter_freeze() that will simply find the
deepest idle state available to the given CPU and enter it using
cpuidle_enter().

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
2015-02-13 23:49:36 +01:00
Daniel Lezcano
442bf3aaf5 sched: Let the scheduler see CPU idle states
When the cpu enters idle, it stores the cpuidle state pointer in its
struct rq instance which in turn could be used to make a better decision
when balancing tasks.

As soon as the cpu exits its idle state, the struct rq reference is
cleared.

There are a couple of situations where the idle state pointer could be changed
while it is being consulted:

1. For x86/acpi with dynamic c-states, when a laptop switches from battery
   to AC that could result on removing the deeper idle state. The acpi driver
   triggers:
	'acpi_processor_cst_has_changed'
		'cpuidle_pause_and_lock'
			'cpuidle_uninstall_idle_handler'
				'kick_all_cpus_sync'.

All cpus will exit their idle state and the pointed object will be set to
NULL.

2. The cpuidle driver is unloaded. Logically that could happen but not
in practice because the drivers are always compiled in and 95% of them are
not coded to unregister themselves.  In any case, the unloading code must
call 'cpuidle_unregister_device', that calls 'cpuidle_pause_and_lock'
leading to 'kick_all_cpus_sync' as mentioned above.

A race can happen if we use the pointer and then one of these two scenarios
occurs at the same moment.

In order to be safe, the idle state pointer stored in the rq must be
used inside a rcu_read_lock section where we are protected with the
'rcu_barrier' in the 'cpuidle_uninstall_idle_handler' function. The
idle_get_state() and idle_put_state() accessors should be used to that
effect.

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: linux-pm@vger.kernel.org
Cc: linaro-kernel@lists.linaro.org
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/n/tip-@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-09-24 14:46:58 +02:00
Chuansheng Liu
2ed903c548 cpuidle: Use wake_up_all_idle_cpus() to wake up all idle cpus
Currently kick_all_cpus_sync() or smp_call_function() can not
break the polling idle cpu immediately.

Instead using wake_up_all_idle_cpus() which can wake up the polling idle
cpu quickly is much more helpful for power.

Signed-off-by: Chuansheng Liu <chuansheng.liu@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: linux-pm@vger.kernel.org
Cc: changcheng.liu@intel.com
Cc: xiaoming.wang@intel.com
Cc: souvik.k.chakravarty@intel.com
Cc: luto@amacapital.net
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
Cc: linux-pm@vger.kernel.org
Link: http://lkml.kernel.org/r/1409815075-4180-3-git-send-email-chuansheng.liu@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-09-19 12:35:16 +02:00
Sandeep Tripathy
30fe688402 cpuidle: move idle traces to cpuidle_enter_state()
idle_exit event is the first event after a core exits
idle state. So this should be traced before local irq
is ebabled. Likewise idle_entry is the last event before
a core enters idle state. This will ease visualising the
cpu idle state from kernel traces.

Signed-off-by: Sandeep Tripathy <sandeep.tripathy@linaro.org>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
[rjw: Subject, rebase]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2014-07-09 15:45:23 +02:00
Rafael J. Wysocki
a6220fc19a PM / suspend: Always use deepest C-state in the "freeze" sleep state
If freeze_enter() is called, we want to bypass the current cpuidle
governor and always use the deepest available (that is, not disabled)
C-state, because we want to save as much energy as reasonably possible
then and runtime latency constraints don't matter at that point, since
the system is in a sleep state anyway.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Aubrey Li <aubrey.li@linux.intel.com>
2014-05-07 01:49:28 +02:00
Rafael J. Wysocki
52c324f8a8 cpuidle: Combine cpuidle_enabled() with cpuidle_select()
Since both cpuidle_enabled() and cpuidle_select() are only called by
cpuidle_idle_call(), it is not really useful to keep them separate
and combining them will help to avoid complicating cpuidle_idle_call()
even further if governors are changed to return error codes sometimes.

This code modification shouldn't lead to any functional changes.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2014-05-01 00:13:47 +02:00
Linus Torvalds
05bf58ca4b Merge branch 'sched-idle-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull sched/idle changes from Ingo Molnar:
 "More idle code reorganization, to prepare for more integration.

  (Sent separately because it depended on pending timer work, which is
  now upstream)"

* 'sched-idle-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched/idle: Add more comments to the code
  sched/idle: Move idle conditions in cpuidle_idle main function
  sched/idle: Reorganize the idle loop
  cpuidle/idle: Move the cpuidle_idle_call function to idle.c
  idle/cpuidle: Split cpuidle_idle_call main function into smaller functions
2014-04-02 16:22:27 -07:00
Linus Torvalds
4dedde7c7a ACPI and power management updates for 3.15-rc1
- Device PM QoS support for latency tolerance constraints on systems with
    hardware interfaces allowing such constraints to be specified.  That is
    necessary to prevent hardware-driven power management from becoming
    overly aggressive on some systems and to prevent power management
    features leading to excessive latencies from being used in some cases.
 
  - Consolidation of the handling of ACPI hotplug notifications for device
    objects.  This causes all device hotplug notifications to go through
    the root notify handler (that was executed for all of them anyway
    before) that propagates them to individual subsystems, if necessary,
    by executing callbacks provided by those subsystems (those callbacks
    are associated with struct acpi_device objects during device
    enumeration).  As a result, the code in question becomes both smaller
    in size and more straightforward and all of those changes should not
    affect users.
 
  - ACPICA update, including fixes related to the handling of _PRT in cases
    when it is broken and the addition of "Windows 2013" to the list of
    supported "features" for _OSI (which is necessary to support systems
    that work incorrectly or don't even boot without it).  Changes from
    Bob Moore and Lv Zheng.
 
  - Consolidation of ACPI _OST handling from Jiang Liu.
 
  - ACPI battery and AC fixes allowing unusual system configurations to
    be handled by that code from Alexander Mezin.
 
  - New device IDs for the ACPI LPSS driver from Chiau Ee Chew.
 
  - ACPI fan and thermal optimizations related to system suspend and resume
    from Aaron Lu.
 
  - Cleanups related to ACPI video from Jean Delvare.
 
  - Assorted ACPI fixes and cleanups from Al Stone, Hanjun Guo, Lan Tianyu,
    Paul Bolle, Tomasz Nowicki.
 
  - Intel RAPL (Running Average Power Limits) driver cleanups from Jacob Pan.
 
  - intel_pstate fixes and cleanups from Dirk Brandewie.
 
  - cpufreq fixes related to system suspend/resume handling from Viresh Kumar.
 
  - cpufreq core fixes and cleanups from Viresh Kumar, Stratos Karafotis,
    Saravana Kannan, Rashika Kheria, Joe Perches.
 
  - cpufreq drivers updates from Viresh Kumar, Zhuoyu Zhang, Rob Herring.
 
  - cpuidle fixes related to the menu governor from Tuukka Tikkanen.
 
  - cpuidle fix related to coupled CPUs handling from Paul Burton.
 
  - Asynchronous execution of all device suspend and resume callbacks,
    except for ->prepare and ->complete, during system suspend and resume
    from Chuansheng Liu.
 
  - Delayed resuming of runtime-suspended devices during system suspend for
    the PCI bus type and ACPI PM domain.
 
  - New set of PM helper routines to allow device runtime PM callbacks to
    be used during system suspend and resume more easily from Ulf Hansson.
 
  - Assorted fixes and cleanups in the PM core from Geert Uytterhoeven,
    Prabhakar Lad, Philipp Zabel, Rashika Kheria, Sebastian Capella.
 
  - devfreq fix from Saravana Kannan.
 
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Merge tag 'pm+acpi-3.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

Pull ACPI and power management updates from Rafael Wysocki:
 "The majority of this material spent some time in linux-next, some of
  it even several weeks.  There are a few relatively fresh commits in
  it, but they are mostly fixes and simple cleanups.

  ACPI took the lead this time, both in terms of the number of commits
  and the number of modified lines of code, cpufreq follows and there
  are a few changes in the PM core and in cpuidle too.

  A new feature that already got some LWN.net's attention is the device
  PM QoS extension allowing latency tolerance requirements to be
  propagated from leaf devices to their ancestors with hardware
  interfaces for specifying latency tolerance.  That should help systems
  with hardware-driven power management to avoid going too far with it
  in cases when there are latency tolerance constraints.

  There also are some significant changes in the ACPI core related to
  the way in which hotplug notifications are handled.  They affect PCI
  hotplug (ACPIPHP) and the ACPI dock station code too.  The bottom line
  is that all those notification now go through the root notify handler
  and are propagated to the interested subsystems by means of callbacks
  instead of having to install a notify handler for each device object
  that we can potentially get hotplug notifications for.

  In addition to that ACPICA will now advertise "Windows 2013"
  compatibility for _OSI, because some systems out there don't work
  correctly if that is not done (some of them don't even boot).

  On the system suspend side of things, all of the device suspend and
  resume callbacks, except for ->prepare() and ->complete(), are now
  going to be executed asynchronously as that turns out to speed up
  system suspend and resume on some platforms quite significantly and we
  have a few more optimizations in that area.

  Apart from that, there are some new device IDs and fixes and cleanups
  all over.  In particular, the system suspend and resume handling by
  cpufreq should be improved and the cpuidle menu governor should be a
  bit more robust now.

  Specifics:

   - Device PM QoS support for latency tolerance constraints on systems
     with hardware interfaces allowing such constraints to be specified.
     That is necessary to prevent hardware-driven power management from
     becoming overly aggressive on some systems and to prevent power
     management features leading to excessive latencies from being used
     in some cases.

   - Consolidation of the handling of ACPI hotplug notifications for
     device objects.  This causes all device hotplug notifications to go
     through the root notify handler (that was executed for all of them
     anyway before) that propagates them to individual subsystems, if
     necessary, by executing callbacks provided by those subsystems
     (those callbacks are associated with struct acpi_device objects
     during device enumeration).  As a result, the code in question
     becomes both smaller in size and more straightforward and all of
     those changes should not affect users.

   - ACPICA update, including fixes related to the handling of _PRT in
     cases when it is broken and the addition of "Windows 2013" to the
     list of supported "features" for _OSI (which is necessary to
     support systems that work incorrectly or don't even boot without
     it).  Changes from Bob Moore and Lv Zheng.

   - Consolidation of ACPI _OST handling from Jiang Liu.

   - ACPI battery and AC fixes allowing unusual system configurations to
     be handled by that code from Alexander Mezin.

   - New device IDs for the ACPI LPSS driver from Chiau Ee Chew.

   - ACPI fan and thermal optimizations related to system suspend and
     resume from Aaron Lu.

   - Cleanups related to ACPI video from Jean Delvare.

   - Assorted ACPI fixes and cleanups from Al Stone, Hanjun Guo, Lan
     Tianyu, Paul Bolle, Tomasz Nowicki.

   - Intel RAPL (Running Average Power Limits) driver cleanups from
     Jacob Pan.

   - intel_pstate fixes and cleanups from Dirk Brandewie.

   - cpufreq fixes related to system suspend/resume handling from Viresh
     Kumar.

   - cpufreq core fixes and cleanups from Viresh Kumar, Stratos
     Karafotis, Saravana Kannan, Rashika Kheria, Joe Perches.

   - cpufreq drivers updates from Viresh Kumar, Zhuoyu Zhang, Rob
     Herring.

   - cpuidle fixes related to the menu governor from Tuukka Tikkanen.

   - cpuidle fix related to coupled CPUs handling from Paul Burton.

   - Asynchronous execution of all device suspend and resume callbacks,
     except for ->prepare and ->complete, during system suspend and
     resume from Chuansheng Liu.

   - Delayed resuming of runtime-suspended devices during system suspend
     for the PCI bus type and ACPI PM domain.

   - New set of PM helper routines to allow device runtime PM callbacks
     to be used during system suspend and resume more easily from Ulf
     Hansson.

   - Assorted fixes and cleanups in the PM core from Geert Uytterhoeven,
     Prabhakar Lad, Philipp Zabel, Rashika Kheria, Sebastian Capella.

   - devfreq fix from Saravana Kannan"

* tag 'pm+acpi-3.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (162 commits)
  PM / devfreq: Rewrite devfreq_update_status() to fix multiple bugs
  PM / sleep: Correct whitespace errors in <linux/pm.h>
  intel_pstate: Set core to min P state during core offline
  cpufreq: Add stop CPU callback to cpufreq_driver interface
  cpufreq: Remove unnecessary braces
  cpufreq: Fix checkpatch errors and warnings
  cpufreq: powerpc: add cpufreq transition latency for FSL e500mc SoCs
  MAINTAINERS: Reorder maintainer addresses for PM and ACPI
  PM / Runtime: Update runtime_idle() documentation for return value meaning
  video / output: Drop display output class support
  fujitsu-laptop: Drop unneeded include
  acer-wmi: Stop selecting VIDEO_OUTPUT_CONTROL
  ACPI / gpu / drm: Stop selecting VIDEO_OUTPUT_CONTROL
  ACPI / video: fix ACPI_VIDEO dependencies
  cpufreq: remove unused notifier: CPUFREQ_{SUSPENDCHANGE|RESUMECHANGE}
  cpufreq: Do not allow ->setpolicy drivers to provide ->target
  cpufreq: arm_big_little: set 'physical_cluster' for each CPU
  cpufreq: arm_big_little: make vexpress driver depend on bL core driver
  ACPI / button: Add ACPI Button event via netlink routine
  ACPI: Remove duplicate definitions of PREFIX
  ...
2014-04-01 12:48:54 -07:00
Paul Burton
0b89e9aa28 cpuidle: delay enabling interrupts until all coupled CPUs leave idle
As described by a comment at the end of cpuidle_enter_state_coupled it
can be inefficient for coupled idle states to return with IRQs enabled
since they may proceed to service an interrupt instead of clearing the
coupled idle state. Until they have finished & cleared the idle state
all CPUs coupled with them will spin rather than being able to enter a
safe idle state.

Commits e1689795a7 "cpuidle: Add common time keeping and irq
enabling" and 554c06ba3e "cpuidle: remove en_core_tk_irqen flag" led
to the cpuidle_enter_state enabling interrupts for all idle states,
including coupled ones, making this inefficiency unavoidable by drivers
& the local_irq_enable near the end of cpuidle_enter_state_coupled
redundant. This patch avoids enabling interrupts in cpuidle_enter_state
after a coupled state has been entered, allowing them to remain disabled
until all coupled CPUs have exited the idle state and
cpuidle_enter_state_coupled re-enables them.

Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2014-03-12 00:24:21 +01:00
Daniel Lezcano
30cdd69e2a cpuidle/idle: Move the cpuidle_idle_call function to idle.c
The cpuidle_idle_call does nothing more than calling the three individuals
function and is no longer used by any arch specific code but only in the
cpuidle framework code.

We can move this function into the idle task code to ensure better
proximity to the scheduler code.

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: Nicolas Pitre <nicolas.pitre@linaro.org>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: rjw@rjwysocki.net
Cc: preeti@linux.vnet.ibm.com
Link: http://lkml.kernel.org/r/1393832934-11625-2-git-send-email-daniel.lezcano@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-03-11 11:52:45 +01:00
Daniel Lezcano
907e30f1bb idle/cpuidle: Split cpuidle_idle_call main function into smaller functions
In order to allow better integration between the cpuidle framework and the
scheduler, reducing the distance between these two sub-components will
facilitate this integration by moving part of the cpuidle code in the idle
task file and, because idle.c is in the sched directory, we have access to
the scheduler's private structures.

This patch splits the cpuidle_idle_call main entry function into 3 calls
to a newly added API:

 1. select the idle state
 2. enter the idle state
 3. reflect the idle state

The cpuidle_idle_call calls these three functions to implement the main
idle entry function.

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: rjw@rjwysocki.net
Cc: preeti@linux.vnet.ibm.com
Link: http://lkml.kernel.org/r/1393832934-11625-1-git-send-email-daniel.lezcano@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-03-11 11:52:45 +01:00
Preeti U Murthy
ba8f20c2eb cpuidle: Handle clockevents_notify(BROADCAST_ENTER) failure
Some archs set the CPUIDLE_FLAG_TIMER_STOP flag for idle states in which the
local timers stop. The cpuidle_idle_call() currently handles such idle states
by calling into the broadcast framework so as to wakeup CPUs at their next
wakeup event. With the hrtimer mode of broadcast, the BROADCAST_ENTER call
into the broadcast frameowork can fail for archs that do not have an external
clock device to handle wakeups and the CPU in question has thus to be made
the stand by CPU. This patch handles such cases by failing the call into
cpuidle so that the arch can take some default action. The arch will certainly
not enter a similar idle state because a failed cpuidle call will also implicitly
indicate that the broadcast framework has not registered this CPU to be woken up.
Hence we are safe if we fail the cpuidle call.

In the process move the functions that trace idle statistics just before and
after the entry and exit into idle states respectively. In other
scenarios where the call to cpuidle fails, we end up not tracing idle
entry and exit since a decision on an idle state could not be taken. Similarly
when the call to broadcast framework fails, we skip tracing idle statistics
because we are in no further position to take a decision on an alternative
idle state to enter into.

Signed-off-by: Preeti U Murthy <preeti@linux.vnet.ibm.com>
Cc: deepthi@linux.vnet.ibm.com
Cc: paulmck@linux.vnet.ibm.com
Cc: fweisbec@gmail.com
Cc: paulus@samba.org
Cc: srivatsa.bhat@linux.vnet.ibm.com
Cc: svaidy@linux.vnet.ibm.com
Cc: peterz@infradead.org
Cc: benh@kernel.crashing.org
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: linuxppc-dev@lists.ozlabs.org
Link: http://lkml.kernel.org/r/20140207080652.17187.66344.stgit@preeti.in.ibm.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2014-02-07 15:34:29 +01:00
Konrad Rzeszutek Wilk
813e8e3d6a cpuidle: Check for dev before deregistering it.
If not, we could end up in the unfortunate situation where
we dereference a NULL pointer b/c we have cpuidle disabled.

This is the case when booting under Xen (which uses the
ACPI P/C states but disables the CPU idle driver) - and can
be easily reproduced when booting with cpuidle.off=1.

BUG: unable to handle kernel NULL pointer dereference at           (null)
IP: [<ffffffff8156db4a>] cpuidle_unregister_device+0x2a/0x90
.. snip..
Call Trace:
 [<ffffffff813b15b4>] acpi_processor_power_exit+0x3c/0x5c
 [<ffffffff813af0a9>] acpi_processor_stop+0x61/0xb6
 [<ffffffff814215bf>] __device_release_driver+0fffff81421653>] device_release_driver+0x23/0x30
 [<ffffffff81420ed8>] bus_remove_device+0x108/0x180
 [<ffffffff8141d9d9>] device_del+0x129/0x1c0
 [<ffffffff813cb4b0>] ? unregister_xenbus_watch+0x1f0/0x1f0
 [<ffffffff8141da8e>] device_unregister+0x1e/0x60
 [<ffffffff814243e9>] unregister_cpu+0x39/0x60
 [<ffffffff81019e03>] arch_unregister_cpu+0x23/0x30
 [<ffffffff813c3c51>] handle_vcpu_hotplug_event+0xc1/0xe0
 [<ffffffff813cb4f5>] xenwatch_thread+0x45/0x120
 [<ffffffff810af010>] ? abort_exclusive_wait+0xb0/0xb0
 [<ffffffff8108ec42>] kthread+0xd2/0xf0
 [<ffffffff8108eb70>] ? kthread_create_on_node+0x180/0x180
 [<ffffffff816ce17c>] ret_from_fork+0x7c/0xb0
 [<ffffffff8108eb70>] ? kthread_create_on_node+0x180/0x180

This problem also appears in 3.12 and could be a candidate for backport.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: All applicable <stable@vger.kernel.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-12-03 22:05:22 +01:00
Viresh Kumar
d7c7f10326 cpuidle: don't call poll_idle_init() for every cpu
poll_idle_init() just initializes drv->states[0] and so that is
required to be done only once for each driver.  Currently, it is
called from cpuidle_enable_device() which is called for every CPU
that the driver supports.  That is not required, so move it to a
better place and call it from __cpuidle_register_driver() so that
the initialization is carried out only once.

Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-10-30 01:21:23 +01:00
Viresh Kumar
6d281e97a1 cpuidle: replace multiline statements with single line in cpuidle_idle_call()
Few statements in cpuidle_idle_call() are broken into multiple lines,
although that isn't really necessary. Convert those to single line.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-10-30 01:21:23 +01:00
Viresh Kumar
fb11c9c63f cpuidle: reduce code duplication inside cpuidle_idle_call()
We are doing this twice in cpuidle_idle_call() routine:
	drv->states[next_state].flags & CPUIDLE_FLAG_TIMER_STOP

Would be better if we actually store this in a local variable and
use that. That reduces code duplication and likely makes this piece
of code run faster (in case the compiler wasn't able to optimize it
earlier)

[rjw: Cast the result of bitwise AND to bool explicitly using !!]
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-10-30 01:21:22 +01:00
Viresh Kumar
9b29a86f04 cpuidle: merge two if() statements for checking error cases
Two checks cpuidle_idle_call() cause the same error code to be
returned if they fail, so merge them for clarity.

[rjw: Changelog]
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-10-30 01:21:22 +01:00
Viresh Kumar
47182668ca cpuidle: rearrange __cpuidle_register_device() to keep minimal exit points
This patch rearranges __cpuidle_register_device() a bit in order to
reduce the number of exit points in that function.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-10-30 01:21:22 +01:00
Viresh Kumar
267d4bf8ee cpuidle: make __cpuidle_device_init() return void
The only value returned by __cpuidle_device_init() is 0, so it very
well may be a void function.  Make that happen.

[rjw: Changelog]
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-10-30 01:21:21 +01:00
Viresh Kumar
caf4a36e81 cpuidle: Fix comments in cpuidle core
Some comments in cpuidle core files contain trivial mistakes.
This patch fixes them.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-10-30 01:21:21 +01:00
Daniel Lezcano
c878a52d3c cpuidle: Check if device is already registered
Make __cpuidle_register_device() check whether or not the device has
been registered already and return -EBUSY immediately if that's the
case.

[rjw: Changelog]
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-07-15 02:09:48 +02:00
Daniel Lezcano
5df0aa7341 cpuidle: Introduce __cpuidle_device_init()
Add __cpuidle_device_init() for initializing the cpuidle_device
structure.

[rjw: Changelog]
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-07-15 02:09:47 +02:00
Daniel Lezcano
f6bb51a53a cpuidle: Introduce __cpuidle_unregister_device()
To reduce code duplication related to the unregistration of cpuidle
devices, introduce __cpuidle_unregister_device() and move all of the
unregistration code to that function.

[rjw: Changelog]
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-07-15 02:09:47 +02:00
Daniel Lezcano
10b9d3f8a4 cpuidle: Check cpuidle_enable_device() return value
We previously changed the ordering of the cpuidle framework
initialization so that the governors are registered before the
drivers which can register their devices right from the start.

Now, we can safely remove the __cpuidle_register_device() call hack
in cpuidle_enable_device() and check if the driver has been
registered before enabling it.  Then, cpuidle_register_device() can
consistently check the cpuidle_enable_device() return value when
enabling the device.

[rjw: Changelog]
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-07-15 02:09:47 +02:00
Daniel Lezcano
82467a5a88 cpuidle: simplify multiple driver support
Commit bf4d1b5 (cpuidle: support multiple drivers) introduced support
for using multiple cpuidle drivers at the same time.  It added a
couple of new APIs to register the driver per CPU, but that led to
some unnecessary code complexity related to the kernel config options
deciding whether or not the multiple driver support is enabled.  The
code has to work as it did before when the multiple driver support is
not enabled and the multiple driver support has to be compatible with
the previously existing API.

Remove the new API, not used by any driver in the tree yet (but
needed for the HMP cpuidle drivers that will be submitted soon), and
add a new cpumask pointer to the cpuidle driver structure that will
point to the mask of CPUs handled by the given driver.  That will
allow the cpuidle_[un]register_driver() API to be used for the
multiple driver support along with the cpuidle_[un]register()
functions added recently.

[rjw: Changelog]
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-06-11 13:42:38 +02:00
Daniel Lezcano
1c192d047a cpuidle: fix comment format
Fix comment format for the kernel doc script.

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-04-24 00:54:51 +02:00
Daniel Lezcano
4c637b2175 cpuidle: make a single register function for all
The usual scheme to initialize a cpuidle driver on a SMP is:

	cpuidle_register_driver(drv);
	for_each_possible_cpu(cpu) {
		device = &per_cpu(cpuidle_dev, cpu);
		cpuidle_register_device(device);
	}

This code is duplicated in each cpuidle driver.

On UP systems, it is done this way:

	cpuidle_register_driver(drv);
	device = &per_cpu(cpuidle_dev, cpu);
	cpuidle_register_device(device);

On UP, the macro 'for_each_cpu' does one iteration:

#define for_each_cpu(cpu, mask)                 \
        for ((cpu) = 0; (cpu) < 1; (cpu)++, (void)mask)

Hence, the initialization loop is the same for UP than SMP.

Beside, we saw different bugs / mis-initialization / return code unchecked in
the different drivers, the code is duplicated including bugs. After fixing all
these ones, it appears the initialization pattern is the same for everyone.

Please note, some drivers are doing dev->state_count = drv->state_count. This is
not necessary because it is done by the cpuidle_enable_device function in the
cpuidle framework. This is true, until you have the same states for all your
devices. Otherwise, the 'low level' API should be used instead with the specific
initialization for the driver.

Let's add a wrapper function doing this initialization with a cpumask parameter
for the coupled idle states and use it for all the drivers.

That will save a lot of LOC, consolidate the code, and the modifications in the
future could be done in a single place. Another benefit is the consolidation of
the cpuidle_device variable which is now in the cpuidle framework and no longer
spread accross the different arch specific drivers.

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-04-23 13:45:22 +02:00
Daniel Lezcano
554c06ba3e cpuidle: remove en_core_tk_irqen flag
The en_core_tk_irqen flag is set in all the cpuidle driver which
means it is not necessary to specify this flag.

Remove the flag and the code related to it.

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: Kevin Hilman <khilman@linaro.org>  # for mach-omap2/*
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-04-23 13:45:22 +02:00
Daniel Lezcano
b60e6a0eb0 cpuidle : handle clockevent notify from the cpuidle framework
When a cpu enters a deep idle state, the local timers are stopped and
the time framework falls back to the timer device used as a broadcast
timer.

The different cpuidle drivers are calling clockevents_notify ENTER/EXIT
when the idle state stops the local timer.

Add a new flag CPUIDLE_FLAG_TIMER_STOP which can be set by the cpuidle
drivers. If the flag is set, the cpuidle core code takes care of the
notification on behalf of the driver to avoid pointless code duplication.

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-04-01 01:10:27 +02:00
Paul Gortmaker
43720bd601 PM / tracing: remove deprecated power trace API
The text in Documentation said it would be removed in 2.6.41;
the text in the Kconfig said removal in the 3.1 release.  Either
way you look at it, we are well past both, so push it off a cliff.

Note that the POWER_CSTATE and the POWER_PSTATE are part of the
legacy tracing API.  Remove all tracepoints which use these flags.
As can be seen from context, most already have a trace entry via
trace_cpu_idle anyways.

Also, the cpufreq/cpufreq.c PSTATE one is actually unpaired, as
compared to the CSTATE ones which all have a clear start/stop.
As part of this, the trace_power_frequency also becomes orphaned,
so it too is deleted.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-01-26 00:39:12 +01:00
Daniel Lezcano
8aef33a7cf cpuidle: remove the power_specified field in the driver
We realized that the power usage field is never filled and when it
is filled for tegra, the power_specified flag is not set causing all
of these values to be reset when the driver is initialized with
set_power_state().

However, the power_specified flag can be simply removed under the
assumption that the states are always backward sorted, which is the
case with the current code.

This change allows the menu governor select function and the
cpuidle_play_dead() to be simplified.  Moreover, the
set_power_states() function can removed as it does not make sense
any more.

Drop the power_specified flag from struct cpuidle_driver and make
the related changes as described above.

As a consequence, this also fixes the bug where on the dynamic
C-states system, the power fields are not initialized.

[rjw: Changelog]
References: https://bugzilla.kernel.org/show_bug.cgi?id=42870
References: https://bugzilla.kernel.org/show_bug.cgi?id=43349
References: https://lkml.org/lkml/2012/10/16/518
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-01-15 14:18:04 +01:00
Sivaram Nair
0e5537b30d cpuidle: Fix finding state with min power_usage
Since cpuidle_state.power_usage is a signed value, use INT_MAX (instead
of -1) to init the local copies so that functions that tries to find
cpuidle states with minimum power usage works correctly even if they use
non-negative values.

Signed-off-by: Sivaram Nair <sivaramn@nvidia.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-01-03 13:11:05 +01:00
Julius Werner
a474a51549 cpuidle: Measure idle state durations with monotonic clock
Many cpuidle drivers measure their time spent in an idle state by
reading the wallclock time before and after idling and calculating the
difference. This leads to erroneous results when the wallclock time gets
updated by another processor in the meantime, adding that clock
adjustment to the idle state's time counter.

If the clock adjustment was negative, the result is even worse due to an
erroneous cast from int to unsigned long long of the last_residency
variable. The negative 32 bit integer will zero-extend and result in a
forward time jump of roughly four billion milliseconds or 1.3 hours on
the idle state residency counter.

This patch changes all affected cpuidle drivers to either use the
monotonic clock for their measurements or make use of the generic time
measurement wrapper in cpuidle.c, which was already working correctly.
Some superfluous CLIs/STIs in the ACPI code are removed (interrupts
should always already be disabled before entering the idle function, and
not get reenabled until the generic wrapper has performed its second
measurement). It also removes the erroneous cast, making sure that
negative residency values are applied correctly even though they should
not appear anymore.

Signed-off-by: Julius Werner <jwerner@chromium.org>
Reviewed-by: Preeti U Murthy <preeti@linux.vnet.ibm.com>
Tested-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: Len Brown <len.brown@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2012-11-27 14:17:58 +01:00
Daniel Lezcano
bf4d1b5ddb cpuidle: support multiple drivers
With the tegra3 and the big.LITTLE [1] new architectures, several cpus
with different characteristics (latencies and states) can co-exists on the
system.

The cpuidle framework has the limitation of handling only identical cpus.

This patch removes this limitation by introducing the multiple driver support
for cpuidle.

This option is configurable at compile time and should be enabled for the
architectures mentioned above. So there is no impact for the other platforms
if the option is disabled. The option defaults to 'n'. Note the multiple drivers
support is also compatible with the existing drivers, even if just one driver is
needed, all the cpu will be tied to this driver using an extra small chunk of
processor memory.

The multiple driver support use a per-cpu driver pointer instead of a global
variable and the accessor to this variable are done from a cpu context.

In order to keep the compatibility with the existing drivers, the function
'cpuidle_register_driver' and 'cpuidle_unregister_driver' will register
the specified driver for all the cpus.

The semantic for the output of /sys/devices/system/cpu/cpuidle/current_driver
remains the same except the driver name will be related to the current cpu.

The /sys/devices/system/cpu/cpu[0-9]/cpuidle/driver/name files are added
allowing to read the per cpu driver name.

[1] http://lwn.net/Articles/481055/

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: Peter De Schrijver <pdeschrijver@nvidia.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2012-11-15 00:34:23 +01:00
Youquan Song
d73d68dc49 cpuidle: Set residency to 0 if target Cstate not enter
When cpuidle governor choose a C-state to enter for idle CPU, but it notice that
there is tasks request to be executed. So the idle CPU will not really enter
the target C-state and go to run task.

In this situation, it will use the residency of previous really entered target
C-states. Obviously, it is not reasonable.

So, this patch fix it by set the target C-state residency to 0.

Signed-off-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Youquan Song <youquan.song@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2012-11-15 00:34:20 +01:00
Daniel Lezcano
e45a00d679 cpuidle / sysfs: move kobj initialization in the syfs file
Move the kobj initialization and completion in the sysfs.c
and encapsulate the code more.

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2012-11-15 00:34:19 +01:00