[PATCH 0/2] PM: Wakeup sources and async suspend error path bug fix

[PATCH 0/2] PM: Wakeup sources and async suspend error path bug fix

[Rafael J. Wysocki]

Hi,

The following two patches are ready to go into linux-next from my point of
view, so please let me know if there are any objections:

[1/2] - PM / Wakeup: Introduce wakeup source objects and event statistics (v3)

[2/2] - PM: Fix potential issue with failing asynchronous suspend

Thanks,
Rafael

[PATCH 1/2] PM / Wakeup: Introduce wakeup source objects and event statistics (v3)

[Rafael J. Wysocki]

From: Rafael J. Wysocki <rjw@sisk.pl>
Subject: PM / Wakeup: Introduce wakeup source objects and event statistics (v3)

Introduce struct wakeup_source for representing system wakeup sources
within the kernel and for collecting statistics related to them.
Make the recently introduced helper functions pm_wakeup_event(),
pm_stay_awake() and pm_relax() use struct wakeup_source objects
internally, so that wakeup statistics associated with wakeup devices
can be collected and reported in a consistent way (the definition of
pm_relax() is changed, which is harmless, because this function is
not called directly by anyone yet).  Introduce new wakeup-related
sysfs device attributes in /sys/devices/.../power for reporting the
device wakeup statistics.

Change the global wakeup events counters event_count and
events_in_progress into atomic variables, so that it is not necessary
to acquire a global spinlock in pm_wakeup_event(), pm_stay_awake()
and pm_relax(), which should allow us to avoid lock contention in
these functions on SMP systems with many wakeup devices.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
---

Changes since v2:

* Use smp_mb__before_atomic_dec() instead of wmb() in
  wakeup_source_deactivate().

* Fix some copy-paste mistakes in sysfs-devices-power.

---
 Documentation/ABI/testing/sysfs-devices-power |   70 +++
 drivers/base/power/main.c                     |    4 
 drivers/base/power/power.h                    |    1 
 drivers/base/power/runtime.c                  |    2 
 drivers/base/power/sysfs.c                    |  121 +++++
 drivers/base/power/wakeup.c                   |  534 ++++++++++++++++++++++----
 include/linux/pm.h                            |   16 
 include/linux/pm_wakeup.h                     |  126 ++++--
 include/linux/suspend.h                       |    4 
 kernel/power/main.c                           |    8 
 10 files changed, 757 insertions(+), 129 deletions(-)

Index: linux-2.6/include/linux/pm_wakeup.h
===================================================================
--- linux-2.6.orig/include/linux/pm_wakeup.h
+++ linux-2.6/include/linux/pm_wakeup.h
@@ -2,6 +2,7 @@
  *  pm_wakeup.h - Power management wakeup interface
  *
  *  Copyright (C) 2008 Alan Stern
+ *  Copyright (C) 2010 Rafael J. Wysocki, Novell Inc.
  *
  *  This program is free software; you can redistribute it and/or modify
  *  it under the terms of the GNU General Public License as published by
@@ -27,18 +28,39 @@
 
 #include <linux/types.h>
 
-#ifdef CONFIG_PM
-
-/* Changes to device_may_wakeup take effect on the next pm state change.
+/**
+ * struct wakeup_source - Representation of wakeup sources
  *
- * By default, most devices should leave wakeup disabled.  The exceptions
- * are devices that everyone expects to be wakeup sources: keyboards,
- * power buttons, possibly network interfaces, etc.
+ * @total_time: Total time this wakeup source has been active.
+ * @max_time: Maximum time this wakeup source has been continuously active.
+ * @last_time: Monotonic clock when the wakeup source's was activated last time.
+ * @event_count: Number of signaled wakeup events.
+ * @active_count: Number of times the wakeup sorce was activated.
+ * @relax_count: Number of times the wakeup sorce was deactivated.
+ * @hit_count: Number of times the wakeup sorce might abort system suspend.
+ * @active: Status of the wakeup source.
+ */
+struct wakeup_source {
+	char 			*name;
+	struct list_head	entry;
+	spinlock_t		lock;
+	struct timer_list	timer;
+	unsigned long		timer_expires;
+	ktime_t total_time;
+	ktime_t max_time;
+	ktime_t last_time;
+	unsigned long		event_count;
+	unsigned long		active_count;
+	unsigned long		relax_count;
+	unsigned long		hit_count;
+	unsigned int		active:1;
+};
+
+#ifdef CONFIG_PM_SLEEP
+
+/*
+ * Changes to device_may_wakeup take effect on the next pm state change.
  */
-static inline void device_init_wakeup(struct device *dev, bool val)
-{
-	dev->power.can_wakeup = dev->power.should_wakeup = val;
-}
 
 static inline void device_set_wakeup_capable(struct device *dev, bool capable)
 {
@@ -50,23 +72,32 @@ static inline bool device_can_wakeup(str
 	return dev->power.can_wakeup;
 }
 
-static inline void device_set_wakeup_enable(struct device *dev, bool enable)
-{
-	dev->power.should_wakeup = enable;
-}
+
 
 static inline bool device_may_wakeup(struct device *dev)
 {
-	return dev->power.can_wakeup && dev->power.should_wakeup;
+	return dev->power.can_wakeup && !!dev->power.wakeup;
 }
 
-#else /* !CONFIG_PM */
+/* drivers/base/power/wakeup.c */
+extern struct wakeup_source *wakeup_source_create(const char *name);
+extern void wakeup_source_destroy(struct wakeup_source *ws);
+extern void wakeup_source_add(struct wakeup_source *ws);
+extern void wakeup_source_remove(struct wakeup_source *ws);
+extern struct wakeup_source *wakeup_source_register(const char *name);
+extern void wakeup_source_unregister(struct wakeup_source *ws);
+extern int device_wakeup_enable(struct device *dev);
+extern int device_wakeup_disable(struct device *dev);
+extern int device_init_wakeup(struct device *dev, bool val);
+extern int device_set_wakeup_enable(struct device *dev, bool enable);
+extern void __pm_stay_awake(struct wakeup_source *ws);
+extern void pm_stay_awake(struct device *dev);
+extern void __pm_relax(struct wakeup_source *ws);
+extern void pm_relax(struct device *dev);
+extern void __pm_wakeup_event(struct wakeup_source *ws, unsigned int msec);
+extern void pm_wakeup_event(struct device *dev, unsigned int msec);
 
-/* For some reason the following routines work even without CONFIG_PM */
-static inline void device_init_wakeup(struct device *dev, bool val)
-{
-	dev->power.can_wakeup = val;
-}
+#else /* !CONFIG_PM_SLEEP */
 
 static inline void device_set_wakeup_capable(struct device *dev, bool capable)
 {
@@ -78,15 +109,60 @@ static inline bool device_can_wakeup(str
 	return dev->power.can_wakeup;
 }
 
-static inline void device_set_wakeup_enable(struct device *dev, bool enable)
+static inline bool device_may_wakeup(struct device *dev)
 {
+	return false;
 }
 
-static inline bool device_may_wakeup(struct device *dev)
+static inline struct wakeup_source *wakeup_source_create(const char *name)
 {
-	return false;
+	return NULL;
 }
 
-#endif /* !CONFIG_PM */
+static inline void wakeup_source_destroy(struct wakeup_source *ws) {}
+
+static inline void wakeup_source_add(struct wakeup_source *ws) {}
+
+static inline void wakeup_source_remove(struct wakeup_source *ws) {}
+
+static inline struct wakeup_source *wakeup_source_register(const char *name)
+{
+	return NULL;
+}
+
+static inline void wakeup_source_unregister(struct wakeup_source *ws) {}
+
+static inline int device_wakeup_enable(struct device *dev)
+{
+	return -EINVAL;
+}
+
+static inline int device_wakeup_disable(struct device *dev) {}
+
+static inline int device_init_wakeup(struct device *dev, bool val)
+{
+	dev->power.can_wakeup = val;
+	return val ? -EINVAL : 0;
+}
+
+
+static inline int device_set_wakeup_enable(struct device *dev, bool enable)
+{
+	return -EINVAL;
+}
+
+static inline void __pm_stay_awake(struct wakeup_source *ws) {}
+
+static inline void pm_stay_awake(struct device *dev) {}
+
+static inline void __pm_relax(struct wakeup_source *ws) {}
+
+static inline void pm_relax(struct device *dev) {}
+
+static inline void __pm_wakeup_event(struct wakeup_source *ws, unsigned int msec) {}
+
+static inline void pm_wakeup_event(struct device *dev, unsigned int msec) {}
+
+#endif /* !CONFIG_PM_SLEEP */
 
 #endif /* _LINUX_PM_WAKEUP_H */
Index: linux-2.6/include/linux/pm.h
===================================================================
--- linux-2.6.orig/include/linux/pm.h
+++ linux-2.6/include/linux/pm.h
@@ -448,23 +448,24 @@ enum rpm_request {
 	RPM_REQ_RESUME,
 };
 
+struct wakeup_source;
+
 struct dev_pm_info {
 	pm_message_t		power_state;
 	unsigned int		can_wakeup:1;
-	unsigned int		should_wakeup:1;
 	unsigned		async_suspend:1;
 	enum dpm_state		status;		/* Owned by the PM core */
+	spinlock_t		lock;
 #ifdef CONFIG_PM_SLEEP
 	struct list_head	entry;
 	struct completion	completion;
-	unsigned long		wakeup_count;
+	struct wakeup_source	*wakeup;
 #endif
 #ifdef CONFIG_PM_RUNTIME
 	struct timer_list	suspend_timer;
 	unsigned long		timer_expires;
 	struct work_struct	work;
 	wait_queue_head_t	wait_queue;
-	spinlock_t		lock;
 	atomic_t		usage_count;
 	atomic_t		child_count;
 	unsigned int		disable_depth:3;
@@ -559,11 +560,6 @@ extern void __suspend_report_result(cons
 	} while (0)
 
 extern void device_pm_wait_for_dev(struct device *sub, struct device *dev);
-
-/* drivers/base/power/wakeup.c */
-extern void pm_wakeup_event(struct device *dev, unsigned int msec);
-extern void pm_stay_awake(struct device *dev);
-extern void pm_relax(void);
 #else /* !CONFIG_PM_SLEEP */
 
 #define device_pm_lock() do {} while (0)
@@ -577,10 +573,6 @@ static inline int dpm_suspend_start(pm_m
 #define suspend_report_result(fn, ret)		do {} while (0)
 
 static inline void device_pm_wait_for_dev(struct device *a, struct device *b) {}
-
-static inline void pm_wakeup_event(struct device *dev, unsigned int msec) {}
-static inline void pm_stay_awake(struct device *dev) {}
-static inline void pm_relax(void) {}
 #endif /* !CONFIG_PM_SLEEP */
 
 /* How to reorder dpm_list after device_move() */
Index: linux-2.6/drivers/base/power/wakeup.c
===================================================================
--- linux-2.6.orig/drivers/base/power/wakeup.c
+++ linux-2.6/drivers/base/power/wakeup.c
@@ -11,7 +11,10 @@
 #include <linux/sched.h>
 #include <linux/capability.h>
 #include <linux/suspend.h>
-#include <linux/pm.h>
+
+#include "power.h"
+
+#define TIMEOUT		100
 
 /*
  * If set, the suspend/hibernate code will abort transitions to a sleep state
@@ -20,18 +23,244 @@
 bool events_check_enabled;
 
 /* The counter of registered wakeup events. */
-static unsigned long event_count;
+static atomic_t event_count = ATOMIC_INIT(0);
 /* A preserved old value of event_count. */
-static unsigned long saved_event_count;
+static unsigned int saved_count;
 /* The counter of wakeup events being processed. */
-static unsigned long events_in_progress;
+static atomic_t events_in_progress = ATOMIC_INIT(0);
 
 static DEFINE_SPINLOCK(events_lock);
 
 static void pm_wakeup_timer_fn(unsigned long data);
 
-static DEFINE_TIMER(events_timer, pm_wakeup_timer_fn, 0, 0);
-static unsigned long events_timer_expires;
+static LIST_HEAD(wakeup_sources);
+
+/**
+ * wakeup_source_create - Create a struct wakeup_source object.
+ * @name: Name of the new wakeup source.
+ */
+struct wakeup_source *wakeup_source_create(const char *name)
+{
+	struct wakeup_source *ws;
+
+	ws = kzalloc(sizeof(*ws), GFP_KERNEL);
+	if (!ws)
+		return NULL;
+
+	spin_lock_init(&ws->lock);
+	if (name)
+		ws->name = kstrdup(name, GFP_KERNEL);
+
+	return ws;
+}
+EXPORT_SYMBOL_GPL(wakeup_source_create);
+
+/**
+ * wakeup_source_destroy - Destroy a struct wakeup_source object.
+ * @ws: Wakeup source to destroy.
+ */
+void wakeup_source_destroy(struct wakeup_source *ws)
+{
+	if (!ws)
+		return;
+
+	spin_lock_irq(&ws->lock);
+	while (ws->active) {
+		spin_unlock_irq(&ws->lock);
+
+		schedule_timeout_interruptible(msecs_to_jiffies(TIMEOUT));
+
+		spin_lock_irq(&ws->lock);
+	}
+	spin_unlock_irq(&ws->lock);
+
+	kfree(ws->name);
+	kfree(ws);
+}
+EXPORT_SYMBOL_GPL(wakeup_source_destroy);
+
+/**
+ * wakeup_source_add - Add given object to the list of wakeup sources.
+ * @ws: Wakeup source object to add to the list.
+ */
+void wakeup_source_add(struct wakeup_source *ws)
+{
+	if (WARN_ON(!ws))
+		return;
+
+	setup_timer(&ws->timer, pm_wakeup_timer_fn, (unsigned long)ws);
+	ws->active = false;
+
+	spin_lock_irq(&events_lock);
+	list_add_rcu(&ws->entry, &wakeup_sources);
+	spin_unlock_irq(&events_lock);
+	synchronize_rcu();
+}
+EXPORT_SYMBOL_GPL(wakeup_source_add);
+
+/**
+ * wakeup_source_remove - Remove given object from the wakeup sources list.
+ * @ws: Wakeup source object to remove from the list.
+ */
+void wakeup_source_remove(struct wakeup_source *ws)
+{
+	if (WARN_ON(!ws))
+		return;
+
+	spin_lock_irq(&events_lock);
+	list_del_rcu(&ws->entry);
+	spin_unlock_irq(&events_lock);
+	synchronize_rcu();
+}
+EXPORT_SYMBOL_GPL(wakeup_source_remove);
+
+/**
+ * wakeup_source_register - Create wakeup source and add it to the list.
+ * @name: Name of the wakeup source to register.
+ */
+struct wakeup_source *wakeup_source_register(const char *name)
+{
+	struct wakeup_source *ws;
+
+	ws = wakeup_source_create(name);
+	if (ws)
+		wakeup_source_add(ws);
+
+	return ws;
+}
+EXPORT_SYMBOL_GPL(wakeup_source_register);
+
+/**
+ * wakeup_source_unregister - Remove wakeup source from the list and remove it.
+ * @ws: Wakeup source object to unregister.
+ */
+void wakeup_source_unregister(struct wakeup_source *ws)
+{
+	wakeup_source_remove(ws);
+	wakeup_source_destroy(ws);
+}
+EXPORT_SYMBOL_GPL(wakeup_source_unregister);
+
+/**
+ * device_wakeup_attach - Attach a wakeup source object to a device object.
+ * @dev: Device to handle.
+ * @ws: Wakeup source object to attach to @dev.
+ *
+ * This causes @dev to be treated as a wakeup device.
+ */
+static int device_wakeup_attach(struct device *dev, struct wakeup_source *ws)
+{
+	spin_lock_irq(&dev->power.lock);
+	if (dev->power.wakeup) {
+		spin_unlock_irq(&dev->power.lock);
+		return -EEXIST;
+	}
+	dev->power.wakeup = ws;
+	spin_unlock_irq(&dev->power.lock);
+	return 0;
+}
+
+/**
+ * device_wakeup_enable - Enable given device to be a wakeup source.
+ * @dev: Device to handle.
+ *
+ * Create a wakeup source object, register it and attach it to @dev.
+ */
+int device_wakeup_enable(struct device *dev)
+{
+	struct wakeup_source *ws;
+	int ret;
+
+	if (!dev || !dev->power.can_wakeup)
+		return -EINVAL;
+
+	ws = wakeup_source_register(dev_name(dev));
+	if (!ws)
+		return -ENOMEM;
+
+	ret = device_wakeup_attach(dev, ws);
+	if (ret)
+		wakeup_source_unregister(ws);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(device_wakeup_enable);
+
+/**
+ * device_wakeup_detach - Detach a device's wakeup source object from it.
+ * @dev: Device to detach the wakeup source object from.
+ *
+ * After it returns, @dev will not be treated as a wakeup device any more.
+ */
+static struct wakeup_source *device_wakeup_detach(struct device *dev)
+{
+	struct wakeup_source *ws;
+
+	spin_lock_irq(&dev->power.lock);
+	ws = dev->power.wakeup;
+	dev->power.wakeup = NULL;
+	spin_unlock_irq(&dev->power.lock);
+	return ws;
+}
+
+/**
+ * device_wakeup_disable - Do not regard a device as a wakeup source any more.
+ * @dev: Device to handle.
+ *
+ * Detach the @dev's wakeup source object from it, unregister this wakeup source
+ * object and destroy it.
+ */
+int device_wakeup_disable(struct device *dev)
+{
+	struct wakeup_source *ws;
+
+	if (!dev || !dev->power.can_wakeup)
+		return -EINVAL;
+
+	ws = device_wakeup_detach(dev);
+	if (ws)
+		wakeup_source_unregister(ws);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(device_wakeup_disable);
+
+/**
+ * device_init_wakeup - Device wakeup initialization.
+ * @dev: Device to handle.
+ * @enable: Whether or not to enable @dev as a wakeup device.
+ *
+ * By default, most devices should leave wakeup disabled.  The exceptions are
+ * devices that everyone expects to be wakeup sources: keyboards, power buttons,
+ * possibly network interfaces, etc.
+ */
+int device_init_wakeup(struct device *dev, bool enable)
+{
+	int ret = 0;
+
+	if (enable) {
+		device_set_wakeup_capable(dev, true);
+		ret = device_wakeup_enable(dev);
+	} else {
+		device_set_wakeup_capable(dev, false);
+	}
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(device_init_wakeup);
+
+/**
+ * device_set_wakeup_enable - Enable or disable a device to wake up the system.
+ * @dev: Device to handle.
+ */
+int device_set_wakeup_enable(struct device *dev, bool enable)
+{
+	if (!dev || !dev->power.can_wakeup)
+		return -EINVAL;
+
+	return enable ? device_wakeup_enable(dev) : device_wakeup_disable(dev);
+}
+EXPORT_SYMBOL_GPL(device_set_wakeup_enable);
 
 /*
  * The functions below use the observation that each wakeup event starts a
@@ -55,118 +284,259 @@ static unsigned long events_timer_expire
  * knowledge, however, may not be available to it, so it can simply specify time
  * to wait before the system can be suspended and pass it as the second
  * argument of pm_wakeup_event().
+ *
+ * It is valid to call pm_relax() after pm_wakeup_event(), in which case the
+ * "no suspend" period will be ended either by the pm_relax(), or by the timer
+ * function executed when the timer expires, whichever comes first.
  */
 
 /**
+ * wakup_source_activate - Mark given wakeup source as active.
+ * @ws: Wakeup source to handle.
+ *
+ * Update the @ws' statistics and, if @ws has just been activated, notify the PM
+ * core of the event by incrementing the counter of of wakeup events being
+ * processed.
+ */
+static void wakeup_source_activate(struct wakeup_source *ws)
+{
+	ws->active = true;
+	ws->active_count++;
+	ws->timer_expires = jiffies;
+	ws->last_time = ktime_get();
+
+	atomic_inc(&events_in_progress);
+}
+
+/**
+ * __pm_stay_awake - Notify the PM core of a wakeup event.
+ * @ws: Wakeup source object associated with the source of the event.
+ *
+ * It is safe to call this function from interrupt context.
+ */
+void __pm_stay_awake(struct wakeup_source *ws)
+{
+	unsigned long flags;
+
+	if (!ws)
+		return;
+
+	spin_lock_irqsave(&ws->lock, flags);
+	ws->event_count++;
+	if (!ws->active)
+		wakeup_source_activate(ws);
+	spin_unlock_irqrestore(&ws->lock, flags);
+}
+EXPORT_SYMBOL_GPL(__pm_stay_awake);
+
+/**
  * pm_stay_awake - Notify the PM core that a wakeup event is being processed.
  * @dev: Device the wakeup event is related to.
  *
- * Notify the PM core of a wakeup event (signaled by @dev) by incrementing the
- * counter of wakeup events being processed.  If @dev is not NULL, the counter
- * of wakeup events related to @dev is incremented too.
+ * Notify the PM core of a wakeup event (signaled by @dev) by calling
+ * __pm_stay_awake for the @dev's wakeup source object.
  *
  * Call this function after detecting of a wakeup event if pm_relax() is going
  * to be called directly after processing the event (and possibly passing it to
  * user space for further processing).
- *
- * It is safe to call this function from interrupt context.
  */
 void pm_stay_awake(struct device *dev)
 {
 	unsigned long flags;
 
-	spin_lock_irqsave(&events_lock, flags);
-	if (dev)
-		dev->power.wakeup_count++;
+	if (!dev)
+		return;
 
-	events_in_progress++;
-	spin_unlock_irqrestore(&events_lock, flags);
+	spin_lock_irqsave(&dev->power.lock, flags);
+	__pm_stay_awake(dev->power.wakeup);
+	spin_unlock_irqrestore(&dev->power.lock, flags);
 }
+EXPORT_SYMBOL_GPL(pm_stay_awake);
 
 /**
- * pm_relax - Notify the PM core that processing of a wakeup event has ended.
+ * wakup_source_deactivate - Mark given wakeup source as inactive.
+ * @ws: Wakeup source to handle.
  *
- * Notify the PM core that a wakeup event has been processed by decrementing
- * the counter of wakeup events being processed and incrementing the counter
- * of registered wakeup events.
+ * Update the @ws' statistics and notify the PM core that the wakeup source has
+ * become inactive by decrementing the counter of wakeup events being processed
+ * and incrementing the counter of registered wakeup events.
+ */
+static void wakeup_source_deactivate(struct wakeup_source *ws)
+{
+	ktime_t duration;
+	ktime_t now;
+
+	ws->relax_count++;
+	/*
+	 * __pm_relax() may be called directly or from a timer function.
+	 * If it is called directly right after the timer function has been
+	 * started, but before the timer function calls __pm_relax(), it is
+	 * possible that __pm_stay_awake() will be called in the meantime and
+	 * will set ws->active.  Then, ws->active may be cleared immediately
+	 * by the __pm_relax() called from the timer function, but in such a
+	 * case ws->relax_count will be different from ws->active_count.
+	 */
+	if (ws->relax_count != ws->active_count) {
+		ws->relax_count--;
+		return;
+	}
+
+	ws->active = false;
+
+	now = ktime_get();
+	duration = ktime_sub(now, ws->last_time);
+	ws->total_time = ktime_add(ws->total_time, duration);
+	if (ktime_to_ns(duration) > ktime_to_ns(ws->max_time))
+		ws->max_time = duration;
+
+	del_timer(&ws->timer);
+
+	/*
+	 * event_count has to be incremented before events_in_progress is
+	 * modified, so that the callers of pm_check_wakeup_events() and
+	 * pm_save_wakeup_count() don't see the old value of event_count and
+	 * events_in_progress equal to zero at the same time.
+	 */
+	atomic_inc(&event_count);
+	smp_mb__before_atomic_dec();
+	atomic_dec(&events_in_progress);
+}
+
+/**
+ * __pm_relax - Notify the PM core that processing of a wakeup event has ended.
+ * @ws: Wakeup source object associated with the source of the event.
  *
  * Call this function for wakeup events whose processing started with calling
- * pm_stay_awake().
+ * __pm_stay_awake().
  *
  * It is safe to call it from interrupt context.
  */
-void pm_relax(void)
+void __pm_relax(struct wakeup_source *ws)
 {
 	unsigned long flags;
 
-	spin_lock_irqsave(&events_lock, flags);
-	if (events_in_progress) {
-		events_in_progress--;
-		event_count++;
-	}
-	spin_unlock_irqrestore(&events_lock, flags);
+	if (!ws)
+		return;
+
+	spin_lock_irqsave(&ws->lock, flags);
+	if (ws->active)
+		wakeup_source_deactivate(ws);
+	spin_unlock_irqrestore(&ws->lock, flags);
 }
+EXPORT_SYMBOL_GPL(__pm_relax);
+
+/**
+ * pm_relax - Notify the PM core that processing of a wakeup event has ended.
+ * @dev: Device that signaled the event.
+ *
+ * Execute __pm_relax() for the @dev's wakeup source object.
+ */
+void pm_relax(struct device *dev)
+{
+	unsigned long flags;
+
+	if (!dev)
+		return;
+
+	spin_lock_irqsave(&dev->power.lock, flags);
+	__pm_relax(dev->power.wakeup);
+	spin_unlock_irqrestore(&dev->power.lock, flags);
+}
+EXPORT_SYMBOL_GPL(pm_relax);
 
 /**
  * pm_wakeup_timer_fn - Delayed finalization of a wakeup event.
+ * @data: Address of the wakeup source object associated with the event source.
  *
- * Decrease the counter of wakeup events being processed after it was increased
- * by pm_wakeup_event().
+ * Call __pm_relax() for the wakeup source whose address is stored in @data.
  */
 static void pm_wakeup_timer_fn(unsigned long data)
 {
+	__pm_relax((struct wakeup_source *)data);
+}
+
+/**
+ * __pm_wakeup_event - Notify the PM core of a wakeup event.
+ * @ws: Wakeup source object associated with the event source.
+ * @msec: Anticipated event processing time (in milliseconds).
+ *
+ * Notify the PM core of a wakeup event whose source is @ws that will take
+ * approximately @msec milliseconds to be processed by the kernel.  If @ws is
+ * not active, activate it.  If @msec is nonzero, set up the @ws' timer to
+ * execute pm_wakeup_timer_fn() in future.
+ *
+ * It is safe to call this function from interrupt context.
+ */
+void __pm_wakeup_event(struct wakeup_source *ws, unsigned int msec)
+{
 	unsigned long flags;
+	unsigned long expires;
 
-	spin_lock_irqsave(&events_lock, flags);
-	if (events_timer_expires
-	    && time_before_eq(events_timer_expires, jiffies)) {
-		events_in_progress--;
-		events_timer_expires = 0;
+	if (!ws)
+		return;
+
+	spin_lock_irqsave(&ws->lock, flags);
+
+	ws->event_count++;
+	if (!ws->active)
+		wakeup_source_activate(ws);
+
+	if (!msec) {
+		wakeup_source_deactivate(ws);
+		goto unlock;
 	}
-	spin_unlock_irqrestore(&events_lock, flags);
+
+	expires = jiffies + msecs_to_jiffies(msec);
+	if (!expires)
+		expires = 1;
+
+	if (time_after(expires, ws->timer_expires)) {
+		mod_timer(&ws->timer, expires);
+		ws->timer_expires = expires;
+	}
+
+ unlock:
+	spin_unlock_irqrestore(&ws->lock, flags);
 }
+EXPORT_SYMBOL_GPL(__pm_wakeup_event);
+
 
 /**
  * pm_wakeup_event - Notify the PM core of a wakeup event.
  * @dev: Device the wakeup event is related to.
  * @msec: Anticipated event processing time (in milliseconds).
  *
- * Notify the PM core of a wakeup event (signaled by @dev) that will take
- * approximately @msec milliseconds to be processed by the kernel.  Increment
- * the counter of registered wakeup events and (if @msec is nonzero) set up
- * the wakeup events timer to execute pm_wakeup_timer_fn() in future (if the
- * timer has not been set up already, increment the counter of wakeup events
- * being processed).  If @dev is not NULL, the counter of wakeup events related
- * to @dev is incremented too.
- *
- * It is safe to call this function from interrupt context.
+ * Call __pm_wakeup_event() for the @dev's wakeup source object.
  */
 void pm_wakeup_event(struct device *dev, unsigned int msec)
 {
 	unsigned long flags;
 
-	spin_lock_irqsave(&events_lock, flags);
-	event_count++;
-	if (dev)
-		dev->power.wakeup_count++;
-
-	if (msec) {
-		unsigned long expires;
-
-		expires = jiffies + msecs_to_jiffies(msec);
-		if (!expires)
-			expires = 1;
-
-		if (!events_timer_expires
-		    || time_after(expires, events_timer_expires)) {
-			if (!events_timer_expires)
-				events_in_progress++;
-
-			mod_timer(&events_timer, expires);
-			events_timer_expires = expires;
-		}
+	if (!dev)
+		return;
+
+	spin_lock_irqsave(&dev->power.lock, flags);
+	__pm_wakeup_event(dev->power.wakeup, msec);
+	spin_unlock_irqrestore(&dev->power.lock, flags);
+}
+EXPORT_SYMBOL_GPL(pm_wakeup_event);
+
+/**
+ * pm_wakeup_update_hit_counts - Update hit counts of all active wakeup sources.
+ */
+static void pm_wakeup_update_hit_counts(void)
+{
+	unsigned long flags;
+	struct wakeup_source *ws;
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(ws, &wakeup_sources, entry) {
+		spin_lock_irqsave(&ws->lock, flags);
+		if (ws->active)
+			ws->hit_count++;
+		spin_unlock_irqrestore(&ws->lock, flags);
 	}
-	spin_unlock_irqrestore(&events_lock, flags);
+	rcu_read_unlock();
 }
 
 /**
@@ -184,10 +554,13 @@ bool pm_check_wakeup_events(void)
 
 	spin_lock_irqsave(&events_lock, flags);
 	if (events_check_enabled) {
-		ret = (event_count == saved_event_count) && !events_in_progress;
+		ret = ((unsigned int)atomic_read(&event_count) == saved_count)
+			&& !atomic_read(&events_in_progress);
 		events_check_enabled = ret;
 	}
 	spin_unlock_irqrestore(&events_lock, flags);
+	if (!ret)
+		pm_wakeup_update_hit_counts();
 	return ret;
 }
 
@@ -202,24 +575,20 @@ bool pm_check_wakeup_events(void)
  * drop down to zero has been interrupted by a signal (and the current number
  * of wakeup events being processed is still nonzero).  Otherwise return true.
  */
-bool pm_get_wakeup_count(unsigned long *count)
+bool pm_get_wakeup_count(unsigned int *count)
 {
 	bool ret;
 
-	spin_lock_irq(&events_lock);
 	if (capable(CAP_SYS_ADMIN))
 		events_check_enabled = false;
 
-	while (events_in_progress && !signal_pending(current)) {
-		spin_unlock_irq(&events_lock);
-
-		schedule_timeout_interruptible(msecs_to_jiffies(100));
-
-		spin_lock_irq(&events_lock);
+	while (atomic_read(&events_in_progress) && !signal_pending(current)) {
+		pm_wakeup_update_hit_counts();
+		schedule_timeout_interruptible(msecs_to_jiffies(TIMEOUT));
 	}
-	*count = event_count;
-	ret = !events_in_progress;
-	spin_unlock_irq(&events_lock);
+
+	ret = !atomic_read(&events_in_progress);
+	*count = atomic_read(&event_count);
 	return ret;
 }
 
@@ -232,16 +601,19 @@ bool pm_get_wakeup_count(unsigned long *
  * old number of registered wakeup events to be used by pm_check_wakeup_events()
  * and return true.  Otherwise return false.
  */
-bool pm_save_wakeup_count(unsigned long count)
+bool pm_save_wakeup_count(unsigned int count)
 {
 	bool ret = false;
 
 	spin_lock_irq(&events_lock);
-	if (count == event_count && !events_in_progress) {
-		saved_event_count = count;
+	if (count == (unsigned int)atomic_read(&event_count)
+	    && !atomic_read(&events_in_progress)) {
+		saved_count = count;
 		events_check_enabled = true;
 		ret = true;
 	}
 	spin_unlock_irq(&events_lock);
+	if (!ret)
+		pm_wakeup_update_hit_counts();
 	return ret;
 }
Index: linux-2.6/drivers/base/power/main.c
===================================================================
--- linux-2.6.orig/drivers/base/power/main.c
+++ linux-2.6/drivers/base/power/main.c
@@ -60,7 +60,8 @@ void device_pm_init(struct device *dev)
 	dev->power.status = DPM_ON;
 	init_completion(&dev->power.completion);
 	complete_all(&dev->power.completion);
-	dev->power.wakeup_count = 0;
+	dev->power.wakeup = NULL;
+	spin_lock_init(&dev->power.lock);
 	pm_runtime_init(dev);
 }
 
@@ -120,6 +121,7 @@ void device_pm_remove(struct device *dev
 	mutex_lock(&dpm_list_mtx);
 	list_del_init(&dev->power.entry);
 	mutex_unlock(&dpm_list_mtx);
+	device_wakeup_disable(dev);
 	pm_runtime_remove(dev);
 }
 
Index: linux-2.6/drivers/base/power/power.h
===================================================================
--- linux-2.6.orig/drivers/base/power/power.h
+++ linux-2.6/drivers/base/power/power.h
@@ -34,6 +34,7 @@ extern void device_pm_move_last(struct d
 
 static inline void device_pm_init(struct device *dev)
 {
+	spin_lock_init(&dev->power.lock);
 	pm_runtime_init(dev);
 }
 
Index: linux-2.6/drivers/base/power/runtime.c
===================================================================
--- linux-2.6.orig/drivers/base/power/runtime.c
+++ linux-2.6/drivers/base/power/runtime.c
@@ -1099,8 +1099,6 @@ EXPORT_SYMBOL_GPL(pm_runtime_allow);
  */
 void pm_runtime_init(struct device *dev)
 {
-	spin_lock_init(&dev->power.lock);
-
 	dev->power.runtime_status = RPM_SUSPENDED;
 	dev->power.idle_notification = false;
 
Index: linux-2.6/include/linux/suspend.h
===================================================================
--- linux-2.6.orig/include/linux/suspend.h
+++ linux-2.6/include/linux/suspend.h
@@ -302,8 +302,8 @@ extern int unregister_pm_notifier(struct
 extern bool events_check_enabled;
 
 extern bool pm_check_wakeup_events(void);
-extern bool pm_get_wakeup_count(unsigned long *count);
-extern bool pm_save_wakeup_count(unsigned long count);
+extern bool pm_get_wakeup_count(unsigned int *count);
+extern bool pm_save_wakeup_count(unsigned int count);
 #else /* !CONFIG_PM_SLEEP */
 
 static inline int register_pm_notifier(struct notifier_block *nb)
Index: linux-2.6/kernel/power/main.c
===================================================================
--- linux-2.6.orig/kernel/power/main.c
+++ linux-2.6/kernel/power/main.c
@@ -237,18 +237,18 @@ static ssize_t wakeup_count_show(struct 
 				struct kobj_attribute *attr,
 				char *buf)
 {
-	unsigned long val;
+	unsigned int val;
 
-	return pm_get_wakeup_count(&val) ? sprintf(buf, "%lu\n", val) : -EINTR;
+	return pm_get_wakeup_count(&val) ? sprintf(buf, "%u\n", val) : -EINTR;
 }
 
 static ssize_t wakeup_count_store(struct kobject *kobj,
 				struct kobj_attribute *attr,
 				const char *buf, size_t n)
 {
-	unsigned long val;
+	unsigned int val;
 
-	if (sscanf(buf, "%lu", &val) == 1) {
+	if (sscanf(buf, "%u", &val) == 1) {
 		if (pm_save_wakeup_count(val))
 			return n;
 	}
Index: linux-2.6/drivers/base/power/sysfs.c
===================================================================
--- linux-2.6.orig/drivers/base/power/sysfs.c
+++ linux-2.6/drivers/base/power/sysfs.c
@@ -210,11 +210,122 @@ static DEVICE_ATTR(wakeup, 0644, wake_sh
 static ssize_t wakeup_count_show(struct device *dev,
 				struct device_attribute *attr, char *buf)
 {
-	return sprintf(buf, "%lu\n", dev->power.wakeup_count);
+	unsigned long count = 0;
+	bool enabled = false;
+
+	spin_lock_irq(&dev->power.lock);
+	if (dev->power.wakeup) {
+		count = dev->power.wakeup->event_count;
+		enabled = true;
+	}
+	spin_unlock_irq(&dev->power.lock);
+	return enabled ? sprintf(buf, "%lu\n", count) : sprintf(buf, "\n");
 }
 
 static DEVICE_ATTR(wakeup_count, 0444, wakeup_count_show, NULL);
-#endif
+
+static ssize_t wakeup_active_count_show(struct device *dev,
+				struct device_attribute *attr, char *buf)
+{
+	unsigned long count = 0;
+	bool enabled = false;
+
+	spin_lock_irq(&dev->power.lock);
+	if (dev->power.wakeup) {
+		count = dev->power.wakeup->active_count;
+		enabled = true;
+	}
+	spin_unlock_irq(&dev->power.lock);
+	return enabled ? sprintf(buf, "%lu\n", count) : sprintf(buf, "\n");
+}
+
+static DEVICE_ATTR(wakeup_active_count, 0444, wakeup_active_count_show, NULL);
+
+static ssize_t wakeup_hit_count_show(struct device *dev,
+				struct device_attribute *attr, char *buf)
+{
+	unsigned long count = 0;
+	bool enabled = false;
+
+	spin_lock_irq(&dev->power.lock);
+	if (dev->power.wakeup) {
+		count = dev->power.wakeup->hit_count;
+		enabled = true;
+	}
+	spin_unlock_irq(&dev->power.lock);
+	return enabled ? sprintf(buf, "%lu\n", count) : sprintf(buf, "\n");
+}
+
+static DEVICE_ATTR(wakeup_hit_count, 0444, wakeup_hit_count_show, NULL);
+
+static ssize_t wakeup_active_show(struct device *dev,
+				struct device_attribute *attr, char *buf)
+{
+	unsigned int active = 0;
+	bool enabled = false;
+
+	spin_lock_irq(&dev->power.lock);
+	if (dev->power.wakeup) {
+		active = dev->power.wakeup->active;
+		enabled = true;
+	}
+	spin_unlock_irq(&dev->power.lock);
+	return enabled ? sprintf(buf, "%u\n", active) : sprintf(buf, "\n");
+}
+
+static DEVICE_ATTR(wakeup_active, 0444, wakeup_active_show, NULL);
+
+static ssize_t wakeup_total_time_show(struct device *dev,
+				struct device_attribute *attr, char *buf)
+{
+	s64 msec = 0;
+	bool enabled = false;
+
+	spin_lock_irq(&dev->power.lock);
+	if (dev->power.wakeup) {
+		msec = ktime_to_ms(dev->power.wakeup->total_time);
+		enabled = true;
+	}
+	spin_unlock_irq(&dev->power.lock);
+	return enabled ? sprintf(buf, "%lld\n", msec) : sprintf(buf, "\n");
+}
+
+static DEVICE_ATTR(wakeup_total_time_ms, 0444, wakeup_total_time_show, NULL);
+
+static ssize_t wakeup_max_time_show(struct device *dev,
+				struct device_attribute *attr, char *buf)
+{
+	s64 msec = 0;
+	bool enabled = false;
+
+	spin_lock_irq(&dev->power.lock);
+	if (dev->power.wakeup) {
+		msec = ktime_to_ms(dev->power.wakeup->max_time);
+		enabled = true;
+	}
+	spin_unlock_irq(&dev->power.lock);
+	return enabled ? sprintf(buf, "%lld\n", msec) : sprintf(buf, "\n");
+}
+
+static DEVICE_ATTR(wakeup_max_time_ms, 0444, wakeup_max_time_show, NULL);
+
+static ssize_t wakeup_last_time_show(struct device *dev,
+				struct device_attribute *attr, char *buf)
+{
+	s64 msec = 0;
+	bool enabled = false;
+
+	spin_lock_irq(&dev->power.lock);
+	if (dev->power.wakeup) {
+		msec = ktime_to_ms(dev->power.wakeup->last_time);
+		enabled = true;
+	}
+	spin_unlock_irq(&dev->power.lock);
+	return enabled ? sprintf(buf, "%lld\n", msec) : sprintf(buf, "\n");
+}
+
+static DEVICE_ATTR(wakeup_last_time_ms, 0444, wakeup_last_time_show, NULL);
+#endif /* CONFIG_PM_SLEEP */
 
 #ifdef CONFIG_PM_ADVANCED_DEBUG
 #ifdef CONFIG_PM_RUNTIME
@@ -288,6 +399,12 @@ static struct attribute * power_attrs[] 
 	&dev_attr_wakeup.attr,
 #ifdef CONFIG_PM_SLEEP
 	&dev_attr_wakeup_count.attr,
+	&dev_attr_wakeup_active_count.attr,
+	&dev_attr_wakeup_hit_count.attr,
+	&dev_attr_wakeup_active.attr,
+	&dev_attr_wakeup_total_time_ms.attr,
+	&dev_attr_wakeup_max_time_ms.attr,
+	&dev_attr_wakeup_last_time_ms.attr,
 #endif
 #ifdef CONFIG_PM_ADVANCED_DEBUG
 	&dev_attr_async.attr,
Index: linux-2.6/Documentation/ABI/testing/sysfs-devices-power
===================================================================
--- linux-2.6.orig/Documentation/ABI/testing/sysfs-devices-power
+++ linux-2.6/Documentation/ABI/testing/sysfs-devices-power
@@ -77,3 +77,73 @@ Description:
 		devices this attribute is set to "enabled" by bus type code or
 		device drivers and in that cases it should be safe to leave the
 		default value.
+
+What:		/sys/devices/.../power/wakeup_count
+Date:		September 2010
+Contact:	Rafael J. Wysocki <rjw@sisk.pl>
+Description:
+		The /sys/devices/.../wakeup_count attribute contains the number
+		of signaled wakeup events associated with the device.  This
+		attribute is read-only.  If the device is not enabled to wake up
+		the system from sleep states, this attribute is empty.
+
+What:		/sys/devices/.../power/wakeup_active_count
+Date:		September 2010
+Contact:	Rafael J. Wysocki <rjw@sisk.pl>
+Description:
+		The /sys/devices/.../wakeup_active_count attribute contains the
+		number of times the processing of wakeup events associated with
+		the device was completed (at the kernel level).  This attribute
+		is read-only.  If the device is not enabled to wake up the
+		system from sleep states, this attribute is empty.
+
+What:		/sys/devices/.../power/wakeup_hit_count
+Date:		September 2010
+Contact:	Rafael J. Wysocki <rjw@sisk.pl>
+Description:
+		The /sys/devices/.../wakeup_hit_count attribute contains the
+		number of times the processing of a wakeup event associated with
+		the device might prevent the system from entering a sleep state.
+		This attribute is read-only.  If the device is not enabled to
+		wake up the system from sleep states, this attribute is empty.
+
+What:		/sys/devices/.../power/wakeup_active
+Date:		September 2010
+Contact:	Rafael J. Wysocki <rjw@sisk.pl>
+Description:
+		The /sys/devices/.../wakeup_active attribute contains either 1,
+		or 0, depending on whether or not a wakeup event associated with
+		the device is being processed (1).  This attribute is read-only.
+		If the device is not enabled to wake up the system from sleep
+		states, this attribute is empty.
+
+What:		/sys/devices/.../power/wakeup_total_time_ms
+Date:		September 2010
+Contact:	Rafael J. Wysocki <rjw@sisk.pl>
+Description:
+		The /sys/devices/.../wakeup_total_time_ms attribute contains
+		the total time of processing wakeup events associated with the
+		device, in milliseconds.  This attribute is read-only.  If the
+		device is not enabled to wake up the system from sleep states,
+		this attribute is empty.
+
+What:		/sys/devices/.../power/wakeup_max_time_ms
+Date:		September 2010
+Contact:	Rafael J. Wysocki <rjw@sisk.pl>
+Description:
+		The /sys/devices/.../wakeup_max_time_ms attribute contains
+		the maximum time of processing a single wakeup event associated
+		with the device, in milliseconds.  This attribute is read-only.
+		If the device is not enabled to wake up the system from sleep
+		states, this attribute is empty.
+
+What:		/sys/devices/.../power/wakeup_last_time_ms
+Date:		September 2010
+Contact:	Rafael J. Wysocki <rjw@sisk.pl>
+Description:
+		The /sys/devices/.../wakeup_last_time_ms attribute contains
+		the value of the monotonic clock corresponding to the time of
+		signaling the last wakeup event associated with the device, in
+		milliseconds.  This attribute is read-only.  If the device is
+		not enabled to wake up the system from sleep states, this
+		attribute is empty.

Re: [PATCH 1/2] PM / Wakeup: Introduce wakeup source objects and event statistics (v3)

[Greg KH]

On Mon, Sep 20, 2010 at 07:59:09PM +0200, Rafael J. Wysocki wrote:
> From: Rafael J. Wysocki <rjw@sisk.pl>
> Subject: PM / Wakeup: Introduce wakeup source objects and event statistics (v3)
> 
> Introduce struct wakeup_source for representing system wakeup sources
> within the kernel and for collecting statistics related to them.
> Make the recently introduced helper functions pm_wakeup_event(),
> pm_stay_awake() and pm_relax() use struct wakeup_source objects
> internally, so that wakeup statistics associated with wakeup devices
> can be collected and reported in a consistent way (the definition of
> pm_relax() is changed, which is harmless, because this function is
> not called directly by anyone yet).  Introduce new wakeup-related
> sysfs device attributes in /sys/devices/.../power for reporting the
> device wakeup statistics.
> 
> Change the global wakeup events counters event_count and
> events_in_progress into atomic variables, so that it is not necessary
> to acquire a global spinlock in pm_wakeup_event(), pm_stay_awake()
> and pm_relax(), which should allow us to avoid lock contention in
> these functions on SMP systems with many wakeup devices.
> 
> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

Acked-by: Greg Kroah-Hartman <gregkh@suse.de>

Nice job!

Re: [PATCH 1/2] PM / Wakeup: Introduce wakeup source objects and event statistics (v3)

[Greg KH]

On Mon, Sep 20, 2010 at 07:59:09PM +0200, Rafael J. Wysocki wrote:
> From: Rafael J. Wysocki <rjw@sisk.pl>
> Subject: PM / Wakeup: Introduce wakeup source objects and event statistics (v3)
> 
> Introduce struct wakeup_source for representing system wakeup sources
> within the kernel and for collecting statistics related to them.
> Make the recently introduced helper functions pm_wakeup_event(),
> pm_stay_awake() and pm_relax() use struct wakeup_source objects
> internally, so that wakeup statistics associated with wakeup devices
> can be collected and reported in a consistent way (the definition of
> pm_relax() is changed, which is harmless, because this function is
> not called directly by anyone yet).  Introduce new wakeup-related
> sysfs device attributes in /sys/devices/.../power for reporting the
> device wakeup statistics.
> 
> Change the global wakeup events counters event_count and
> events_in_progress into atomic variables, so that it is not necessary
> to acquire a global spinlock in pm_wakeup_event(), pm_stay_awake()
> and pm_relax(), which should allow us to avoid lock contention in
> these functions on SMP systems with many wakeup devices.
> 
> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

Acked-by: Greg Kroah-Hartman <gregkh@suse.de>

Nice job!

[PATCH 1/2] PM / Wakeup: Introduce wakeup source objects and event statistics (v3)

[Rafael J. Wysocki]

From: Rafael J. Wysocki <rjw@sisk.pl>
Subject: PM / Wakeup: Introduce wakeup source objects and event statistics (v3)

Introduce struct wakeup_source for representing system wakeup sources
within the kernel and for collecting statistics related to them.
Make the recently introduced helper functions pm_wakeup_event(),
pm_stay_awake() and pm_relax() use struct wakeup_source objects
internally, so that wakeup statistics associated with wakeup devices
can be collected and reported in a consistent way (the definition of
pm_relax() is changed, which is harmless, because this function is
not called directly by anyone yet).  Introduce new wakeup-related
sysfs device attributes in /sys/devices/.../power for reporting the
device wakeup statistics.

Change the global wakeup events counters event_count and
events_in_progress into atomic variables, so that it is not necessary
to acquire a global spinlock in pm_wakeup_event(), pm_stay_awake()
and pm_relax(), which should allow us to avoid lock contention in
these functions on SMP systems with many wakeup devices.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
---

Changes since v2:

* Use smp_mb__before_atomic_dec() instead of wmb() in
  wakeup_source_deactivate().

* Fix some copy-paste mistakes in sysfs-devices-power.

---
 Documentation/ABI/testing/sysfs-devices-power |   70 +++
 drivers/base/power/main.c                     |    4 
 drivers/base/power/power.h                    |    1 
 drivers/base/power/runtime.c                  |    2 
 drivers/base/power/sysfs.c                    |  121 +++++
 drivers/base/power/wakeup.c                   |  534 ++++++++++++++++++++++----
 include/linux/pm.h                            |   16 
 include/linux/pm_wakeup.h                     |  126 ++++--
 include/linux/suspend.h                       |    4 
 kernel/power/main.c                           |    8 
 10 files changed, 757 insertions(+), 129 deletions(-)

Index: linux-2.6/include/linux/pm_wakeup.h
===================================================================
--- linux-2.6.orig/include/linux/pm_wakeup.h
+++ linux-2.6/include/linux/pm_wakeup.h
@@ -2,6 +2,7 @@
  *  pm_wakeup.h - Power management wakeup interface
  *
  *  Copyright (C) 2008 Alan Stern
+ *  Copyright (C) 2010 Rafael J. Wysocki, Novell Inc.
  *
  *  This program is free software; you can redistribute it and/or modify
  *  it under the terms of the GNU General Public License as published by
@@ -27,18 +28,39 @@
 
 #include <linux/types.h>
 
-#ifdef CONFIG_PM
-
-/* Changes to device_may_wakeup take effect on the next pm state change.
+/**
+ * struct wakeup_source - Representation of wakeup sources
  *
- * By default, most devices should leave wakeup disabled.  The exceptions
- * are devices that everyone expects to be wakeup sources: keyboards,
- * power buttons, possibly network interfaces, etc.
+ * @total_time: Total time this wakeup source has been active.
+ * @max_time: Maximum time this wakeup source has been continuously active.
+ * @last_time: Monotonic clock when the wakeup source's was activated last time.
+ * @event_count: Number of signaled wakeup events.
+ * @active_count: Number of times the wakeup sorce was activated.
+ * @relax_count: Number of times the wakeup sorce was deactivated.
+ * @hit_count: Number of times the wakeup sorce might abort system suspend.
+ * @active: Status of the wakeup source.
+ */
+struct wakeup_source {
+	char 			*name;
+	struct list_head	entry;
+	spinlock_t		lock;
+	struct timer_list	timer;
+	unsigned long		timer_expires;
+	ktime_t total_time;
+	ktime_t max_time;
+	ktime_t last_time;
+	unsigned long		event_count;
+	unsigned long		active_count;
+	unsigned long		relax_count;
+	unsigned long		hit_count;
+	unsigned int		active:1;
+};
+
+#ifdef CONFIG_PM_SLEEP
+
+/*
+ * Changes to device_may_wakeup take effect on the next pm state change.
  */
-static inline void device_init_wakeup(struct device *dev, bool val)
-{
-	dev->power.can_wakeup = dev->power.should_wakeup = val;
-}
 
 static inline void device_set_wakeup_capable(struct device *dev, bool capable)
 {
@@ -50,23 +72,32 @@ static inline bool device_can_wakeup(str
 	return dev->power.can_wakeup;
 }
 
-static inline void device_set_wakeup_enable(struct device *dev, bool enable)
-{
-	dev->power.should_wakeup = enable;
-}
+
 
 static inline bool device_may_wakeup(struct device *dev)
 {
-	return dev->power.can_wakeup && dev->power.should_wakeup;
+	return dev->power.can_wakeup && !!dev->power.wakeup;
 }
 
-#else /* !CONFIG_PM */
+/* drivers/base/power/wakeup.c */
+extern struct wakeup_source *wakeup_source_create(const char *name);
+extern void wakeup_source_destroy(struct wakeup_source *ws);
+extern void wakeup_source_add(struct wakeup_source *ws);
+extern void wakeup_source_remove(struct wakeup_source *ws);
+extern struct wakeup_source *wakeup_source_register(const char *name);
+extern void wakeup_source_unregister(struct wakeup_source *ws);
+extern int device_wakeup_enable(struct device *dev);
+extern int device_wakeup_disable(struct device *dev);
+extern int device_init_wakeup(struct device *dev, bool val);
+extern int device_set_wakeup_enable(struct device *dev, bool enable);
+extern void __pm_stay_awake(struct wakeup_source *ws);
+extern void pm_stay_awake(struct device *dev);
+extern void __pm_relax(struct wakeup_source *ws);
+extern void pm_relax(struct device *dev);
+extern void __pm_wakeup_event(struct wakeup_source *ws, unsigned int msec);
+extern void pm_wakeup_event(struct device *dev, unsigned int msec);
 
-/* For some reason the following routines work even without CONFIG_PM */
-static inline void device_init_wakeup(struct device *dev, bool val)
-{
-	dev->power.can_wakeup = val;
-}
+#else /* !CONFIG_PM_SLEEP */
 
 static inline void device_set_wakeup_capable(struct device *dev, bool capable)
 {
@@ -78,15 +109,60 @@ static inline bool device_can_wakeup(str
 	return dev->power.can_wakeup;
 }
 
-static inline void device_set_wakeup_enable(struct device *dev, bool enable)
+static inline bool device_may_wakeup(struct device *dev)
 {
+	return false;
 }
 
-static inline bool device_may_wakeup(struct device *dev)
+static inline struct wakeup_source *wakeup_source_create(const char *name)
 {
-	return false;
+	return NULL;
 }
 
-#endif /* !CONFIG_PM */
+static inline void wakeup_source_destroy(struct wakeup_source *ws) {}
+
+static inline void wakeup_source_add(struct wakeup_source *ws) {}
+
+static inline void wakeup_source_remove(struct wakeup_source *ws) {}
+
+static inline struct wakeup_source *wakeup_source_register(const char *name)
+{
+	return NULL;
+}
+
+static inline void wakeup_source_unregister(struct wakeup_source *ws) {}
+
+static inline int device_wakeup_enable(struct device *dev)
+{
+	return -EINVAL;
+}
+
+static inline int device_wakeup_disable(struct device *dev) {}
+
+static inline int device_init_wakeup(struct device *dev, bool val)
+{
+	dev->power.can_wakeup = val;
+	return val ? -EINVAL : 0;
+}
+
+
+static inline int device_set_wakeup_enable(struct device *dev, bool enable)
+{
+	return -EINVAL;
+}
+
+static inline void __pm_stay_awake(struct wakeup_source *ws) {}
+
+static inline void pm_stay_awake(struct device *dev) {}
+
+static inline void __pm_relax(struct wakeup_source *ws) {}
+
+static inline void pm_relax(struct device *dev) {}
+
+static inline void __pm_wakeup_event(struct wakeup_source *ws, unsigned int msec) {}
+
+static inline void pm_wakeup_event(struct device *dev, unsigned int msec) {}
+
+#endif /* !CONFIG_PM_SLEEP */
 
 #endif /* _LINUX_PM_WAKEUP_H */
Index: linux-2.6/include/linux/pm.h
===================================================================
--- linux-2.6.orig/include/linux/pm.h
+++ linux-2.6/include/linux/pm.h
@@ -448,23 +448,24 @@ enum rpm_request {
 	RPM_REQ_RESUME,
 };
 
+struct wakeup_source;
+
 struct dev_pm_info {
 	pm_message_t		power_state;
 	unsigned int		can_wakeup:1;
-	unsigned int		should_wakeup:1;
 	unsigned		async_suspend:1;
 	enum dpm_state		status;		/* Owned by the PM core */
+	spinlock_t		lock;
 #ifdef CONFIG_PM_SLEEP
 	struct list_head	entry;
 	struct completion	completion;
-	unsigned long		wakeup_count;
+	struct wakeup_source	*wakeup;
 #endif
 #ifdef CONFIG_PM_RUNTIME
 	struct timer_list	suspend_timer;
 	unsigned long		timer_expires;
 	struct work_struct	work;
 	wait_queue_head_t	wait_queue;
-	spinlock_t		lock;
 	atomic_t		usage_count;
 	atomic_t		child_count;
 	unsigned int		disable_depth:3;
@@ -559,11 +560,6 @@ extern void __suspend_report_result(cons
 	} while (0)
 
 extern void device_pm_wait_for_dev(struct device *sub, struct device *dev);
-
-/* drivers/base/power/wakeup.c */
-extern void pm_wakeup_event(struct device *dev, unsigned int msec);
-extern void pm_stay_awake(struct device *dev);
-extern void pm_relax(void);
 #else /* !CONFIG_PM_SLEEP */
 
 #define device_pm_lock() do {} while (0)
@@ -577,10 +573,6 @@ static inline int dpm_suspend_start(pm_m
 #define suspend_report_result(fn, ret)		do {} while (0)
 
 static inline void device_pm_wait_for_dev(struct device *a, struct device *b) {}
-
-static inline void pm_wakeup_event(struct device *dev, unsigned int msec) {}
-static inline void pm_stay_awake(struct device *dev) {}
-static inline void pm_relax(void) {}
 #endif /* !CONFIG_PM_SLEEP */
 
 /* How to reorder dpm_list after device_move() */
Index: linux-2.6/drivers/base/power/wakeup.c
===================================================================
--- linux-2.6.orig/drivers/base/power/wakeup.c
+++ linux-2.6/drivers/base/power/wakeup.c
@@ -11,7 +11,10 @@
 #include <linux/sched.h>
 #include <linux/capability.h>
 #include <linux/suspend.h>
-#include <linux/pm.h>
+
+#include "power.h"
+
+#define TIMEOUT		100
 
 /*
  * If set, the suspend/hibernate code will abort transitions to a sleep state
@@ -20,18 +23,244 @@
 bool events_check_enabled;
 
 /* The counter of registered wakeup events. */
-static unsigned long event_count;
+static atomic_t event_count = ATOMIC_INIT(0);
 /* A preserved old value of event_count. */
-static unsigned long saved_event_count;
+static unsigned int saved_count;
 /* The counter of wakeup events being processed. */
-static unsigned long events_in_progress;
+static atomic_t events_in_progress = ATOMIC_INIT(0);
 
 static DEFINE_SPINLOCK(events_lock);
 
 static void pm_wakeup_timer_fn(unsigned long data);
 
-static DEFINE_TIMER(events_timer, pm_wakeup_timer_fn, 0, 0);
-static unsigned long events_timer_expires;
+static LIST_HEAD(wakeup_sources);
+
+/**
+ * wakeup_source_create - Create a struct wakeup_source object.
+ * @name: Name of the new wakeup source.
+ */
+struct wakeup_source *wakeup_source_create(const char *name)
+{
+	struct wakeup_source *ws;
+
+	ws = kzalloc(sizeof(*ws), GFP_KERNEL);
+	if (!ws)
+		return NULL;
+
+	spin_lock_init(&ws->lock);
+	if (name)
+		ws->name = kstrdup(name, GFP_KERNEL);
+
+	return ws;
+}
+EXPORT_SYMBOL_GPL(wakeup_source_create);
+
+/**
+ * wakeup_source_destroy - Destroy a struct wakeup_source object.
+ * @ws: Wakeup source to destroy.
+ */
+void wakeup_source_destroy(struct wakeup_source *ws)
+{
+	if (!ws)
+		return;
+
+	spin_lock_irq(&ws->lock);
+	while (ws->active) {
+		spin_unlock_irq(&ws->lock);
+
+		schedule_timeout_interruptible(msecs_to_jiffies(TIMEOUT));
+
+		spin_lock_irq(&ws->lock);
+	}
+	spin_unlock_irq(&ws->lock);
+
+	kfree(ws->name);
+	kfree(ws);
+}
+EXPORT_SYMBOL_GPL(wakeup_source_destroy);
+
+/**
+ * wakeup_source_add - Add given object to the list of wakeup sources.
+ * @ws: Wakeup source object to add to the list.
+ */
+void wakeup_source_add(struct wakeup_source *ws)
+{
+	if (WARN_ON(!ws))
+		return;
+
+	setup_timer(&ws->timer, pm_wakeup_timer_fn, (unsigned long)ws);
+	ws->active = false;
+
+	spin_lock_irq(&events_lock);
+	list_add_rcu(&ws->entry, &wakeup_sources);
+	spin_unlock_irq(&events_lock);
+	synchronize_rcu();
+}
+EXPORT_SYMBOL_GPL(wakeup_source_add);
+
+/**
+ * wakeup_source_remove - Remove given object from the wakeup sources list.
+ * @ws: Wakeup source object to remove from the list.
+ */
+void wakeup_source_remove(struct wakeup_source *ws)
+{
+	if (WARN_ON(!ws))
+		return;
+
+	spin_lock_irq(&events_lock);
+	list_del_rcu(&ws->entry);
+	spin_unlock_irq(&events_lock);
+	synchronize_rcu();
+}
+EXPORT_SYMBOL_GPL(wakeup_source_remove);
+
+/**
+ * wakeup_source_register - Create wakeup source and add it to the list.
+ * @name: Name of the wakeup source to register.
+ */
+struct wakeup_source *wakeup_source_register(const char *name)
+{
+	struct wakeup_source *ws;
+
+	ws = wakeup_source_create(name);
+	if (ws)
+		wakeup_source_add(ws);
+
+	return ws;
+}
+EXPORT_SYMBOL_GPL(wakeup_source_register);
+
+/**
+ * wakeup_source_unregister - Remove wakeup source from the list and remove it.
+ * @ws: Wakeup source object to unregister.
+ */
+void wakeup_source_unregister(struct wakeup_source *ws)
+{
+	wakeup_source_remove(ws);
+	wakeup_source_destroy(ws);
+}
+EXPORT_SYMBOL_GPL(wakeup_source_unregister);
+
+/**
+ * device_wakeup_attach - Attach a wakeup source object to a device object.
+ * @dev: Device to handle.
+ * @ws: Wakeup source object to attach to @dev.
+ *
+ * This causes @dev to be treated as a wakeup device.
+ */
+static int device_wakeup_attach(struct device *dev, struct wakeup_source *ws)
+{
+	spin_lock_irq(&dev->power.lock);
+	if (dev->power.wakeup) {
+		spin_unlock_irq(&dev->power.lock);
+		return -EEXIST;
+	}
+	dev->power.wakeup = ws;
+	spin_unlock_irq(&dev->power.lock);
+	return 0;
+}
+
+/**
+ * device_wakeup_enable - Enable given device to be a wakeup source.
+ * @dev: Device to handle.
+ *
+ * Create a wakeup source object, register it and attach it to @dev.
+ */
+int device_wakeup_enable(struct device *dev)
+{
+	struct wakeup_source *ws;
+	int ret;
+
+	if (!dev || !dev->power.can_wakeup)
+		return -EINVAL;
+
+	ws = wakeup_source_register(dev_name(dev));
+	if (!ws)
+		return -ENOMEM;
+
+	ret = device_wakeup_attach(dev, ws);
+	if (ret)
+		wakeup_source_unregister(ws);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(device_wakeup_enable);
+
+/**
+ * device_wakeup_detach - Detach a device's wakeup source object from it.
+ * @dev: Device to detach the wakeup source object from.
+ *
+ * After it returns, @dev will not be treated as a wakeup device any more.
+ */
+static struct wakeup_source *device_wakeup_detach(struct device *dev)
+{
+	struct wakeup_source *ws;
+
+	spin_lock_irq(&dev->power.lock);
+	ws = dev->power.wakeup;
+	dev->power.wakeup = NULL;
+	spin_unlock_irq(&dev->power.lock);
+	return ws;
+}
+
+/**
+ * device_wakeup_disable - Do not regard a device as a wakeup source any more.
+ * @dev: Device to handle.
+ *
+ * Detach the @dev's wakeup source object from it, unregister this wakeup source
+ * object and destroy it.
+ */
+int device_wakeup_disable(struct device *dev)
+{
+	struct wakeup_source *ws;
+
+	if (!dev || !dev->power.can_wakeup)
+		return -EINVAL;
+
+	ws = device_wakeup_detach(dev);
+	if (ws)
+		wakeup_source_unregister(ws);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(device_wakeup_disable);
+
+/**
+ * device_init_wakeup - Device wakeup initialization.
+ * @dev: Device to handle.
+ * @enable: Whether or not to enable @dev as a wakeup device.
+ *
+ * By default, most devices should leave wakeup disabled.  The exceptions are
+ * devices that everyone expects to be wakeup sources: keyboards, power buttons,
+ * possibly network interfaces, etc.
+ */
+int device_init_wakeup(struct device *dev, bool enable)
+{
+	int ret = 0;
+
+	if (enable) {
+		device_set_wakeup_capable(dev, true);
+		ret = device_wakeup_enable(dev);
+	} else {
+		device_set_wakeup_capable(dev, false);
+	}
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(device_init_wakeup);
+
+/**
+ * device_set_wakeup_enable - Enable or disable a device to wake up the system.
+ * @dev: Device to handle.
+ */
+int device_set_wakeup_enable(struct device *dev, bool enable)
+{
+	if (!dev || !dev->power.can_wakeup)
+		return -EINVAL;
+
+	return enable ? device_wakeup_enable(dev) : device_wakeup_disable(dev);
+}
+EXPORT_SYMBOL_GPL(device_set_wakeup_enable);
 
 /*
  * The functions below use the observation that each wakeup event starts a
@@ -55,118 +284,259 @@ static unsigned long events_timer_expire
  * knowledge, however, may not be available to it, so it can simply specify time
  * to wait before the system can be suspended and pass it as the second
  * argument of pm_wakeup_event().
+ *
+ * It is valid to call pm_relax() after pm_wakeup_event(), in which case the
+ * "no suspend" period will be ended either by the pm_relax(), or by the timer
+ * function executed when the timer expires, whichever comes first.
  */
 
 /**
+ * wakup_source_activate - Mark given wakeup source as active.
+ * @ws: Wakeup source to handle.
+ *
+ * Update the @ws' statistics and, if @ws has just been activated, notify the PM
+ * core of the event by incrementing the counter of of wakeup events being
+ * processed.
+ */
+static void wakeup_source_activate(struct wakeup_source *ws)
+{
+	ws->active = true;
+	ws->active_count++;
+	ws->timer_expires = jiffies;
+	ws->last_time = ktime_get();
+
+	atomic_inc(&events_in_progress);
+}
+
+/**
+ * __pm_stay_awake - Notify the PM core of a wakeup event.
+ * @ws: Wakeup source object associated with the source of the event.
+ *
+ * It is safe to call this function from interrupt context.
+ */
+void __pm_stay_awake(struct wakeup_source *ws)
+{
+	unsigned long flags;
+
+	if (!ws)
+		return;
+
+	spin_lock_irqsave(&ws->lock, flags);
+	ws->event_count++;
+	if (!ws->active)
+		wakeup_source_activate(ws);
+	spin_unlock_irqrestore(&ws->lock, flags);
+}
+EXPORT_SYMBOL_GPL(__pm_stay_awake);
+
+/**
  * pm_stay_awake - Notify the PM core that a wakeup event is being processed.
  * @dev: Device the wakeup event is related to.
  *
- * Notify the PM core of a wakeup event (signaled by @dev) by incrementing the
- * counter of wakeup events being processed.  If @dev is not NULL, the counter
- * of wakeup events related to @dev is incremented too.
+ * Notify the PM core of a wakeup event (signaled by @dev) by calling
+ * __pm_stay_awake for the @dev's wakeup source object.
  *
  * Call this function after detecting of a wakeup event if pm_relax() is going
  * to be called directly after processing the event (and possibly passing it to
  * user space for further processing).
- *
- * It is safe to call this function from interrupt context.
  */
 void pm_stay_awake(struct device *dev)
 {
 	unsigned long flags;
 
-	spin_lock_irqsave(&events_lock, flags);
-	if (dev)
-		dev->power.wakeup_count++;
+	if (!dev)
+		return;
 
-	events_in_progress++;
-	spin_unlock_irqrestore(&events_lock, flags);
+	spin_lock_irqsave(&dev->power.lock, flags);
+	__pm_stay_awake(dev->power.wakeup);
+	spin_unlock_irqrestore(&dev->power.lock, flags);
 }
+EXPORT_SYMBOL_GPL(pm_stay_awake);
 
 /**
- * pm_relax - Notify the PM core that processing of a wakeup event has ended.
+ * wakup_source_deactivate - Mark given wakeup source as inactive.
+ * @ws: Wakeup source to handle.
  *
- * Notify the PM core that a wakeup event has been processed by decrementing
- * the counter of wakeup events being processed and incrementing the counter
- * of registered wakeup events.
+ * Update the @ws' statistics and notify the PM core that the wakeup source has
+ * become inactive by decrementing the counter of wakeup events being processed
+ * and incrementing the counter of registered wakeup events.
+ */
+static void wakeup_source_deactivate(struct wakeup_source *ws)
+{
+	ktime_t duration;
+	ktime_t now;
+
+	ws->relax_count++;
+	/*
+	 * __pm_relax() may be called directly or from a timer function.
+	 * If it is called directly right after the timer function has been
+	 * started, but before the timer function calls __pm_relax(), it is
+	 * possible that __pm_stay_awake() will be called in the meantime and
+	 * will set ws->active.  Then, ws->active may be cleared immediately
+	 * by the __pm_relax() called from the timer function, but in such a
+	 * case ws->relax_count will be different from ws->active_count.
+	 */
+	if (ws->relax_count != ws->active_count) {
+		ws->relax_count--;
+		return;
+	}
+
+	ws->active = false;
+
+	now = ktime_get();
+	duration = ktime_sub(now, ws->last_time);
+	ws->total_time = ktime_add(ws->total_time, duration);
+	if (ktime_to_ns(duration) > ktime_to_ns(ws->max_time))
+		ws->max_time = duration;
+
+	del_timer(&ws->timer);
+
+	/*
+	 * event_count has to be incremented before events_in_progress is
+	 * modified, so that the callers of pm_check_wakeup_events() and
+	 * pm_save_wakeup_count() don't see the old value of event_count and
+	 * events_in_progress equal to zero at the same time.
+	 */
+	atomic_inc(&event_count);
+	smp_mb__before_atomic_dec();
+	atomic_dec(&events_in_progress);
+}
+
+/**
+ * __pm_relax - Notify the PM core that processing of a wakeup event has ended.
+ * @ws: Wakeup source object associated with the source of the event.
  *
  * Call this function for wakeup events whose processing started with calling
- * pm_stay_awake().
+ * __pm_stay_awake().
  *
  * It is safe to call it from interrupt context.
  */
-void pm_relax(void)
+void __pm_relax(struct wakeup_source *ws)
 {
 	unsigned long flags;
 
-	spin_lock_irqsave(&events_lock, flags);
-	if (events_in_progress) {
-		events_in_progress--;
-		event_count++;
-	}
-	spin_unlock_irqrestore(&events_lock, flags);
+	if (!ws)
+		return;
+
+	spin_lock_irqsave(&ws->lock, flags);
+	if (ws->active)
+		wakeup_source_deactivate(ws);
+	spin_unlock_irqrestore(&ws->lock, flags);
 }
+EXPORT_SYMBOL_GPL(__pm_relax);
+
+/**
+ * pm_relax - Notify the PM core that processing of a wakeup event has ended.
+ * @dev: Device that signaled the event.
+ *
+ * Execute __pm_relax() for the @dev's wakeup source object.
+ */
+void pm_relax(struct device *dev)
+{
+	unsigned long flags;
+
+	if (!dev)
+		return;
+
+	spin_lock_irqsave(&dev->power.lock, flags);
+	__pm_relax(dev->power.wakeup);
+	spin_unlock_irqrestore(&dev->power.lock, flags);
+}
+EXPORT_SYMBOL_GPL(pm_relax);
 
 /**
  * pm_wakeup_timer_fn - Delayed finalization of a wakeup event.
+ * @data: Address of the wakeup source object associated with the event source.
  *
- * Decrease the counter of wakeup events being processed after it was increased
- * by pm_wakeup_event().
+ * Call __pm_relax() for the wakeup source whose address is stored in @data.
  */
 static void pm_wakeup_timer_fn(unsigned long data)
 {
+	__pm_relax((struct wakeup_source *)data);
+}
+
+/**
+ * __pm_wakeup_event - Notify the PM core of a wakeup event.
+ * @ws: Wakeup source object associated with the event source.
+ * @msec: Anticipated event processing time (in milliseconds).
+ *
+ * Notify the PM core of a wakeup event whose source is @ws that will take
+ * approximately @msec milliseconds to be processed by the kernel.  If @ws is
+ * not active, activate it.  If @msec is nonzero, set up the @ws' timer to
+ * execute pm_wakeup_timer_fn() in future.
+ *
+ * It is safe to call this function from interrupt context.
+ */
+void __pm_wakeup_event(struct wakeup_source *ws, unsigned int msec)
+{
 	unsigned long flags;
+	unsigned long expires;
 
-	spin_lock_irqsave(&events_lock, flags);
-	if (events_timer_expires
-	    && time_before_eq(events_timer_expires, jiffies)) {
-		events_in_progress--;
-		events_timer_expires = 0;
+	if (!ws)
+		return;
+
+	spin_lock_irqsave(&ws->lock, flags);
+
+	ws->event_count++;
+	if (!ws->active)
+		wakeup_source_activate(ws);
+
+	if (!msec) {
+		wakeup_source_deactivate(ws);
+		goto unlock;
 	}
-	spin_unlock_irqrestore(&events_lock, flags);
+
+	expires = jiffies + msecs_to_jiffies(msec);
+	if (!expires)
+		expires = 1;
+
+	if (time_after(expires, ws->timer_expires)) {
+		mod_timer(&ws->timer, expires);
+		ws->timer_expires = expires;
+	}
+
+ unlock:
+	spin_unlock_irqrestore(&ws->lock, flags);
 }
+EXPORT_SYMBOL_GPL(__pm_wakeup_event);
+
 
 /**
  * pm_wakeup_event - Notify the PM core of a wakeup event.
  * @dev: Device the wakeup event is related to.
  * @msec: Anticipated event processing time (in milliseconds).
  *
- * Notify the PM core of a wakeup event (signaled by @dev) that will take
- * approximately @msec milliseconds to be processed by the kernel.  Increment
- * the counter of registered wakeup events and (if @msec is nonzero) set up
- * the wakeup events timer to execute pm_wakeup_timer_fn() in future (if the
- * timer has not been set up already, increment the counter of wakeup events
- * being processed).  If @dev is not NULL, the counter of wakeup events related
- * to @dev is incremented too.
- *
- * It is safe to call this function from interrupt context.
+ * Call __pm_wakeup_event() for the @dev's wakeup source object.
  */
 void pm_wakeup_event(struct device *dev, unsigned int msec)
 {
 	unsigned long flags;
 
-	spin_lock_irqsave(&events_lock, flags);
-	event_count++;
-	if (dev)
-		dev->power.wakeup_count++;
-
-	if (msec) {
-		unsigned long expires;
-
-		expires = jiffies + msecs_to_jiffies(msec);
-		if (!expires)
-			expires = 1;
-
-		if (!events_timer_expires
-		    || time_after(expires, events_timer_expires)) {
-			if (!events_timer_expires)
-				events_in_progress++;
-
-			mod_timer(&events_timer, expires);
-			events_timer_expires = expires;
-		}
+	if (!dev)
+		return;
+
+	spin_lock_irqsave(&dev->power.lock, flags);
+	__pm_wakeup_event(dev->power.wakeup, msec);
+	spin_unlock_irqrestore(&dev->power.lock, flags);
+}
+EXPORT_SYMBOL_GPL(pm_wakeup_event);
+
+/**
+ * pm_wakeup_update_hit_counts - Update hit counts of all active wakeup sources.
+ */
+static void pm_wakeup_update_hit_counts(void)
+{
+	unsigned long flags;
+	struct wakeup_source *ws;
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(ws, &wakeup_sources, entry) {
+		spin_lock_irqsave(&ws->lock, flags);
+		if (ws->active)
+			ws->hit_count++;
+		spin_unlock_irqrestore(&ws->lock, flags);
 	}
-	spin_unlock_irqrestore(&events_lock, flags);
+	rcu_read_unlock();
 }
 
 /**
@@ -184,10 +554,13 @@ bool pm_check_wakeup_events(void)
 
 	spin_lock_irqsave(&events_lock, flags);
 	if (events_check_enabled) {
-		ret = (event_count == saved_event_count) && !events_in_progress;
+		ret = ((unsigned int)atomic_read(&event_count) == saved_count)
+			&& !atomic_read(&events_in_progress);
 		events_check_enabled = ret;
 	}
 	spin_unlock_irqrestore(&events_lock, flags);
+	if (!ret)
+		pm_wakeup_update_hit_counts();
 	return ret;
 }
 
@@ -202,24 +575,20 @@ bool pm_check_wakeup_events(void)
  * drop down to zero has been interrupted by a signal (and the current number
  * of wakeup events being processed is still nonzero).  Otherwise return true.
  */
-bool pm_get_wakeup_count(unsigned long *count)
+bool pm_get_wakeup_count(unsigned int *count)
 {
 	bool ret;
 
-	spin_lock_irq(&events_lock);
 	if (capable(CAP_SYS_ADMIN))
 		events_check_enabled = false;
 
-	while (events_in_progress && !signal_pending(current)) {
-		spin_unlock_irq(&events_lock);
-
-		schedule_timeout_interruptible(msecs_to_jiffies(100));
-
-		spin_lock_irq(&events_lock);
+	while (atomic_read(&events_in_progress) && !signal_pending(current)) {
+		pm_wakeup_update_hit_counts();
+		schedule_timeout_interruptible(msecs_to_jiffies(TIMEOUT));
 	}
-	*count = event_count;
-	ret = !events_in_progress;
-	spin_unlock_irq(&events_lock);
+
+	ret = !atomic_read(&events_in_progress);
+	*count = atomic_read(&event_count);
 	return ret;
 }
 
@@ -232,16 +601,19 @@ bool pm_get_wakeup_count(unsigned long *
  * old number of registered wakeup events to be used by pm_check_wakeup_events()
  * and return true.  Otherwise return false.
  */
-bool pm_save_wakeup_count(unsigned long count)
+bool pm_save_wakeup_count(unsigned int count)
 {
 	bool ret = false;
 
 	spin_lock_irq(&events_lock);
-	if (count == event_count && !events_in_progress) {
-		saved_event_count = count;
+	if (count == (unsigned int)atomic_read(&event_count)
+	    && !atomic_read(&events_in_progress)) {
+		saved_count = count;
 		events_check_enabled = true;
 		ret = true;
 	}
 	spin_unlock_irq(&events_lock);
+	if (!ret)
+		pm_wakeup_update_hit_counts();
 	return ret;
 }
Index: linux-2.6/drivers/base/power/main.c
===================================================================
--- linux-2.6.orig/drivers/base/power/main.c
+++ linux-2.6/drivers/base/power/main.c
@@ -60,7 +60,8 @@ void device_pm_init(struct device *dev)
 	dev->power.status = DPM_ON;
 	init_completion(&dev->power.completion);
 	complete_all(&dev->power.completion);
-	dev->power.wakeup_count = 0;
+	dev->power.wakeup = NULL;
+	spin_lock_init(&dev->power.lock);
 	pm_runtime_init(dev);
 }
 
@@ -120,6 +121,7 @@ void device_pm_remove(struct device *dev
 	mutex_lock(&dpm_list_mtx);
 	list_del_init(&dev->power.entry);
 	mutex_unlock(&dpm_list_mtx);
+	device_wakeup_disable(dev);
 	pm_runtime_remove(dev);
 }
 
Index: linux-2.6/drivers/base/power/power.h
===================================================================
--- linux-2.6.orig/drivers/base/power/power.h
+++ linux-2.6/drivers/base/power/power.h
@@ -34,6 +34,7 @@ extern void device_pm_move_last(struct d
 
 static inline void device_pm_init(struct device *dev)
 {
+	spin_lock_init(&dev->power.lock);
 	pm_runtime_init(dev);
 }
 
Index: linux-2.6/drivers/base/power/runtime.c
===================================================================
--- linux-2.6.orig/drivers/base/power/runtime.c
+++ linux-2.6/drivers/base/power/runtime.c
@@ -1099,8 +1099,6 @@ EXPORT_SYMBOL_GPL(pm_runtime_allow);
  */
 void pm_runtime_init(struct device *dev)
 {
-	spin_lock_init(&dev->power.lock);
-
 	dev->power.runtime_status = RPM_SUSPENDED;
 	dev->power.idle_notification = false;
 
Index: linux-2.6/include/linux/suspend.h
===================================================================
--- linux-2.6.orig/include/linux/suspend.h
+++ linux-2.6/include/linux/suspend.h
@@ -302,8 +302,8 @@ extern int unregister_pm_notifier(struct
 extern bool events_check_enabled;
 
 extern bool pm_check_wakeup_events(void);
-extern bool pm_get_wakeup_count(unsigned long *count);
-extern bool pm_save_wakeup_count(unsigned long count);
+extern bool pm_get_wakeup_count(unsigned int *count);
+extern bool pm_save_wakeup_count(unsigned int count);
 #else /* !CONFIG_PM_SLEEP */
 
 static inline int register_pm_notifier(struct notifier_block *nb)
Index: linux-2.6/kernel/power/main.c
===================================================================
--- linux-2.6.orig/kernel/power/main.c
+++ linux-2.6/kernel/power/main.c
@@ -237,18 +237,18 @@ static ssize_t wakeup_count_show(struct 
 				struct kobj_attribute *attr,
 				char *buf)
 {
-	unsigned long val;
+	unsigned int val;
 
-	return pm_get_wakeup_count(&val) ? sprintf(buf, "%lu\n", val) : -EINTR;
+	return pm_get_wakeup_count(&val) ? sprintf(buf, "%u\n", val) : -EINTR;
 }
 
 static ssize_t wakeup_count_store(struct kobject *kobj,
 				struct kobj_attribute *attr,
 				const char *buf, size_t n)
 {
-	unsigned long val;
+	unsigned int val;
 
-	if (sscanf(buf, "%lu", &val) == 1) {
+	if (sscanf(buf, "%u", &val) == 1) {
 		if (pm_save_wakeup_count(val))
 			return n;
 	}
Index: linux-2.6/drivers/base/power/sysfs.c
===================================================================
--- linux-2.6.orig/drivers/base/power/sysfs.c
+++ linux-2.6/drivers/base/power/sysfs.c
@@ -210,11 +210,122 @@ static DEVICE_ATTR(wakeup, 0644, wake_sh
 static ssize_t wakeup_count_show(struct device *dev,
 				struct device_attribute *attr, char *buf)
 {
-	return sprintf(buf, "%lu\n", dev->power.wakeup_count);
+	unsigned long count = 0;
+	bool enabled = false;
+
+	spin_lock_irq(&dev->power.lock);
+	if (dev->power.wakeup) {
+		count = dev->power.wakeup->event_count;
+		enabled = true;
+	}
+	spin_unlock_irq(&dev->power.lock);
+	return enabled ? sprintf(buf, "%lu\n", count) : sprintf(buf, "\n");
 }
 
 static DEVICE_ATTR(wakeup_count, 0444, wakeup_count_show, NULL);
-#endif
+
+static ssize_t wakeup_active_count_show(struct device *dev,
+				struct device_attribute *attr, char *buf)
+{
+	unsigned long count = 0;
+	bool enabled = false;
+
+	spin_lock_irq(&dev->power.lock);
+	if (dev->power.wakeup) {
+		count = dev->power.wakeup->active_count;
+		enabled = true;
+	}
+	spin_unlock_irq(&dev->power.lock);
+	return enabled ? sprintf(buf, "%lu\n", count) : sprintf(buf, "\n");
+}
+
+static DEVICE_ATTR(wakeup_active_count, 0444, wakeup_active_count_show, NULL);
+
+static ssize_t wakeup_hit_count_show(struct device *dev,
+				struct device_attribute *attr, char *buf)
+{
+	unsigned long count = 0;
+	bool enabled = false;
+
+	spin_lock_irq(&dev->power.lock);
+	if (dev->power.wakeup) {
+		count = dev->power.wakeup->hit_count;
+		enabled = true;
+	}
+	spin_unlock_irq(&dev->power.lock);
+	return enabled ? sprintf(buf, "%lu\n", count) : sprintf(buf, "\n");
+}
+
+static DEVICE_ATTR(wakeup_hit_count, 0444, wakeup_hit_count_show, NULL);
+
+static ssize_t wakeup_active_show(struct device *dev,
+				struct device_attribute *attr, char *buf)
+{
+	unsigned int active = 0;
+	bool enabled = false;
+
+	spin_lock_irq(&dev->power.lock);
+	if (dev->power.wakeup) {
+		active = dev->power.wakeup->active;
+		enabled = true;
+	}
+	spin_unlock_irq(&dev->power.lock);
+	return enabled ? sprintf(buf, "%u\n", active) : sprintf(buf, "\n");
+}
+
+static DEVICE_ATTR(wakeup_active, 0444, wakeup_active_show, NULL);
+
+static ssize_t wakeup_total_time_show(struct device *dev,
+				struct device_attribute *attr, char *buf)
+{
+	s64 msec = 0;
+	bool enabled = false;
+
+	spin_lock_irq(&dev->power.lock);
+	if (dev->power.wakeup) {
+		msec = ktime_to_ms(dev->power.wakeup->total_time);
+		enabled = true;
+	}
+	spin_unlock_irq(&dev->power.lock);
+	return enabled ? sprintf(buf, "%lld\n", msec) : sprintf(buf, "\n");
+}
+
+static DEVICE_ATTR(wakeup_total_time_ms, 0444, wakeup_total_time_show, NULL);
+
+static ssize_t wakeup_max_time_show(struct device *dev,
+				struct device_attribute *attr, char *buf)
+{
+	s64 msec = 0;
+	bool enabled = false;
+
+	spin_lock_irq(&dev->power.lock);
+	if (dev->power.wakeup) {
+		msec = ktime_to_ms(dev->power.wakeup->max_time);
+		enabled = true;
+	}
+	spin_unlock_irq(&dev->power.lock);
+	return enabled ? sprintf(buf, "%lld\n", msec) : sprintf(buf, "\n");
+}
+
+static DEVICE_ATTR(wakeup_max_time_ms, 0444, wakeup_max_time_show, NULL);
+
+static ssize_t wakeup_last_time_show(struct device *dev,
+				struct device_attribute *attr, char *buf)
+{
+	s64 msec = 0;
+	bool enabled = false;
+
+	spin_lock_irq(&dev->power.lock);
+	if (dev->power.wakeup) {
+		msec = ktime_to_ms(dev->power.wakeup->last_time);
+		enabled = true;
+	}
+	spin_unlock_irq(&dev->power.lock);
+	return enabled ? sprintf(buf, "%lld\n", msec) : sprintf(buf, "\n");
+}
+
+static DEVICE_ATTR(wakeup_last_time_ms, 0444, wakeup_last_time_show, NULL);
+#endif /* CONFIG_PM_SLEEP */
 
 #ifdef CONFIG_PM_ADVANCED_DEBUG
 #ifdef CONFIG_PM_RUNTIME
@@ -288,6 +399,12 @@ static struct attribute * power_attrs[] 
 	&dev_attr_wakeup.attr,
 #ifdef CONFIG_PM_SLEEP
 	&dev_attr_wakeup_count.attr,
+	&dev_attr_wakeup_active_count.attr,
+	&dev_attr_wakeup_hit_count.attr,
+	&dev_attr_wakeup_active.attr,
+	&dev_attr_wakeup_total_time_ms.attr,
+	&dev_attr_wakeup_max_time_ms.attr,
+	&dev_attr_wakeup_last_time_ms.attr,
 #endif
 #ifdef CONFIG_PM_ADVANCED_DEBUG
 	&dev_attr_async.attr,
Index: linux-2.6/Documentation/ABI/testing/sysfs-devices-power
===================================================================
--- linux-2.6.orig/Documentation/ABI/testing/sysfs-devices-power
+++ linux-2.6/Documentation/ABI/testing/sysfs-devices-power
@@ -77,3 +77,73 @@ Description:
 		devices this attribute is set to "enabled" by bus type code or
 		device drivers and in that cases it should be safe to leave the
 		default value.
+
+What:		/sys/devices/.../power/wakeup_count
+Date:		September 2010
+Contact:	Rafael J. Wysocki <rjw@sisk.pl>
+Description:
+		The /sys/devices/.../wakeup_count attribute contains the number
+		of signaled wakeup events associated with the device.  This
+		attribute is read-only.  If the device is not enabled to wake up
+		the system from sleep states, this attribute is empty.
+
+What:		/sys/devices/.../power/wakeup_active_count
+Date:		September 2010
+Contact:	Rafael J. Wysocki <rjw@sisk.pl>
+Description:
+		The /sys/devices/.../wakeup_active_count attribute contains the
+		number of times the processing of wakeup events associated with
+		the device was completed (at the kernel level).  This attribute
+		is read-only.  If the device is not enabled to wake up the
+		system from sleep states, this attribute is empty.
+
+What:		/sys/devices/.../power/wakeup_hit_count
+Date:		September 2010
+Contact:	Rafael J. Wysocki <rjw@sisk.pl>
+Description:
+		The /sys/devices/.../wakeup_hit_count attribute contains the
+		number of times the processing of a wakeup event associated with
+		the device might prevent the system from entering a sleep state.
+		This attribute is read-only.  If the device is not enabled to
+		wake up the system from sleep states, this attribute is empty.
+
+What:		/sys/devices/.../power/wakeup_active
+Date:		September 2010
+Contact:	Rafael J. Wysocki <rjw@sisk.pl>
+Description:
+		The /sys/devices/.../wakeup_active attribute contains either 1,
+		or 0, depending on whether or not a wakeup event associated with
+		the device is being processed (1).  This attribute is read-only.
+		If the device is not enabled to wake up the system from sleep
+		states, this attribute is empty.
+
+What:		/sys/devices/.../power/wakeup_total_time_ms
+Date:		September 2010
+Contact:	Rafael J. Wysocki <rjw@sisk.pl>
+Description:
+		The /sys/devices/.../wakeup_total_time_ms attribute contains
+		the total time of processing wakeup events associated with the
+		device, in milliseconds.  This attribute is read-only.  If the
+		device is not enabled to wake up the system from sleep states,
+		this attribute is empty.
+
+What:		/sys/devices/.../power/wakeup_max_time_ms
+Date:		September 2010
+Contact:	Rafael J. Wysocki <rjw@sisk.pl>
+Description:
+		The /sys/devices/.../wakeup_max_time_ms attribute contains
+		the maximum time of processing a single wakeup event associated
+		with the device, in milliseconds.  This attribute is read-only.
+		If the device is not enabled to wake up the system from sleep
+		states, this attribute is empty.
+
+What:		/sys/devices/.../power/wakeup_last_time_ms
+Date:		September 2010
+Contact:	Rafael J. Wysocki <rjw@sisk.pl>
+Description:
+		The /sys/devices/.../wakeup_last_time_ms attribute contains
+		the value of the monotonic clock corresponding to the time of
+		signaling the last wakeup event associated with the device, in
+		milliseconds.  This attribute is read-only.  If the device is
+		not enabled to wake up the system from sleep states, this
+		attribute is empty.

[PATCH 2/2] PM: Fix potential issue with failing asynchronous suspend

[Rafael J. Wysocki]

From: Rafael J. Wysocki <rjw@sisk.pl>
Subject: PM: Fix potential issue with failing asynchronous suspend

There is a potential issue with the asynchronous suspend code that
a device driver suspending asynchronously may not notice that it
should back off.  There are two failing scenarions, (1) when the
driver is waiting for a driver suspending synchronously to complete
and that second driver returns error code, in which case async_error
won't be set and the waiting driver will continue suspending and (2)
after the driver has called device_pm_wait_for_dev() and the waited
for driver returns error code, in which case the caller of
device_pm_wait_for_dev() will not know that there was an error and
will continue suspending.

To fix this issue make __device_suspend() set async_error, so
async_suspend() doesn't need to set it any more, and make
device_pm_wait_for_dev() return async_error, so that its callers
can check whether or not they should continue suspending.

No more changes are necessary, since device_pm_wait_for_dev() in
not used by any drivers' suspend routines.

Reported-by: Colin Cross <ccross@android.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
---
 drivers/base/power/main.c |   15 +++++++++------
 include/linux/pm.h        |    7 +++++--
 2 files changed, 14 insertions(+), 8 deletions(-)

Index: linux-2.6/drivers/base/power/main.c
===================================================================
--- linux-2.6.orig/drivers/base/power/main.c
+++ linux-2.6/drivers/base/power/main.c
@@ -51,6 +51,8 @@ static pm_message_t pm_transition;
  */
 static bool transition_started;
 
+static int async_error;
+
 /**
  * device_pm_init - Initialize the PM-related part of a device object.
  * @dev: Device object being initialized.
@@ -602,6 +604,7 @@ static void dpm_resume(pm_message_t stat
 	INIT_LIST_HEAD(&list);
 	mutex_lock(&dpm_list_mtx);
 	pm_transition = state;
+	async_error = 0;
 
 	list_for_each_entry(dev, &dpm_list, power.entry) {
 		if (dev->power.status < DPM_OFF)
@@ -831,8 +834,6 @@ static int legacy_suspend(struct device 
 	return error;
 }
 
-static int async_error;
-
 /**
  * device_suspend - Execute "suspend" callbacks for given device.
  * @dev: Device to handle.
@@ -887,6 +888,9 @@ static int __device_suspend(struct devic
 	device_unlock(dev);
 	complete_all(&dev->power.completion);
 
+	if (error)
+		async_error = error;
+
 	return error;
 }
 
@@ -896,10 +900,8 @@ static void async_suspend(void *data, as
 	int error;
 
 	error = __device_suspend(dev, pm_transition, true);
-	if (error) {
+	if (error)
 		pm_dev_err(dev, pm_transition, " async", error);
-		async_error = error;
-	}
 
 	put_device(dev);
 }
@@ -1087,8 +1089,9 @@ EXPORT_SYMBOL_GPL(__suspend_report_resul
  * @dev: Device to wait for.
  * @subordinate: Device that needs to wait for @dev.
  */
-void device_pm_wait_for_dev(struct device *subordinate, struct device *dev)
+int device_pm_wait_for_dev(struct device *subordinate, struct device *dev)
 {
 	dpm_wait(dev, subordinate->power.async_suspend);
+	return async_error;
 }
 EXPORT_SYMBOL_GPL(device_pm_wait_for_dev);
Index: linux-2.6/include/linux/pm.h
===================================================================
--- linux-2.6.orig/include/linux/pm.h
+++ linux-2.6/include/linux/pm.h
@@ -559,7 +559,7 @@ extern void __suspend_report_result(cons
 		__suspend_report_result(__func__, fn, ret);		\
 	} while (0)
 
-extern void device_pm_wait_for_dev(struct device *sub, struct device *dev);
+extern int device_pm_wait_for_dev(struct device *sub, struct device *dev);
 #else /* !CONFIG_PM_SLEEP */
 
 #define device_pm_lock() do {} while (0)
@@ -572,7 +572,10 @@ static inline int dpm_suspend_start(pm_m
 
 #define suspend_report_result(fn, ret)		do {} while (0)
 
-static inline void device_pm_wait_for_dev(struct device *a, struct device *b) {}
+static inline int device_pm_wait_for_dev(struct device *a, struct device *b)
+{
+	return 0;
+}
 #endif /* !CONFIG_PM_SLEEP */
 
 /* How to reorder dpm_list after device_move() */

[PATCH 2/2] PM: Fix potential issue with failing asynchronous suspend

[Rafael J. Wysocki]

From: Rafael J. Wysocki <rjw@sisk.pl>
Subject: PM: Fix potential issue with failing asynchronous suspend

There is a potential issue with the asynchronous suspend code that
a device driver suspending asynchronously may not notice that it
should back off.  There are two failing scenarions, (1) when the
driver is waiting for a driver suspending synchronously to complete
and that second driver returns error code, in which case async_error
won't be set and the waiting driver will continue suspending and (2)
after the driver has called device_pm_wait_for_dev() and the waited
for driver returns error code, in which case the caller of
device_pm_wait_for_dev() will not know that there was an error and
will continue suspending.

To fix this issue make __device_suspend() set async_error, so
async_suspend() doesn't need to set it any more, and make
device_pm_wait_for_dev() return async_error, so that its callers
can check whether or not they should continue suspending.

No more changes are necessary, since device_pm_wait_for_dev() in
not used by any drivers' suspend routines.

Reported-by: Colin Cross <ccross@android.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
---
 drivers/base/power/main.c |   15 +++++++++------
 include/linux/pm.h        |    7 +++++--
 2 files changed, 14 insertions(+), 8 deletions(-)

Index: linux-2.6/drivers/base/power/main.c
===================================================================
--- linux-2.6.orig/drivers/base/power/main.c
+++ linux-2.6/drivers/base/power/main.c
@@ -51,6 +51,8 @@ static pm_message_t pm_transition;
  */
 static bool transition_started;
 
+static int async_error;
+
 /**
  * device_pm_init - Initialize the PM-related part of a device object.
  * @dev: Device object being initialized.
@@ -602,6 +604,7 @@ static void dpm_resume(pm_message_t stat
 	INIT_LIST_HEAD(&list);
 	mutex_lock(&dpm_list_mtx);
 	pm_transition = state;
+	async_error = 0;
 
 	list_for_each_entry(dev, &dpm_list, power.entry) {
 		if (dev->power.status < DPM_OFF)
@@ -831,8 +834,6 @@ static int legacy_suspend(struct device 
 	return error;
 }
 
-static int async_error;
-
 /**
  * device_suspend - Execute "suspend" callbacks for given device.
  * @dev: Device to handle.
@@ -887,6 +888,9 @@ static int __device_suspend(struct devic
 	device_unlock(dev);
 	complete_all(&dev->power.completion);
 
+	if (error)
+		async_error = error;
+
 	return error;
 }
 
@@ -896,10 +900,8 @@ static void async_suspend(void *data, as
 	int error;
 
 	error = __device_suspend(dev, pm_transition, true);
-	if (error) {
+	if (error)
 		pm_dev_err(dev, pm_transition, " async", error);
-		async_error = error;
-	}
 
 	put_device(dev);
 }
@@ -1087,8 +1089,9 @@ EXPORT_SYMBOL_GPL(__suspend_report_resul
  * @dev: Device to wait for.
  * @subordinate: Device that needs to wait for @dev.
  */
-void device_pm_wait_for_dev(struct device *subordinate, struct device *dev)
+int device_pm_wait_for_dev(struct device *subordinate, struct device *dev)
 {
 	dpm_wait(dev, subordinate->power.async_suspend);
+	return async_error;
 }
 EXPORT_SYMBOL_GPL(device_pm_wait_for_dev);
Index: linux-2.6/include/linux/pm.h
===================================================================
--- linux-2.6.orig/include/linux/pm.h
+++ linux-2.6/include/linux/pm.h
@@ -559,7 +559,7 @@ extern void __suspend_report_result(cons
 		__suspend_report_result(__func__, fn, ret);		\
 	} while (0)
 
-extern void device_pm_wait_for_dev(struct device *sub, struct device *dev);
+extern int device_pm_wait_for_dev(struct device *sub, struct device *dev);
 #else /* !CONFIG_PM_SLEEP */
 
 #define device_pm_lock() do {} while (0)
@@ -572,7 +572,10 @@ static inline int dpm_suspend_start(pm_m
 
 #define suspend_report_result(fn, ret)		do {} while (0)
 
-static inline void device_pm_wait_for_dev(struct device *a, struct device *b) {}
+static inline int device_pm_wait_for_dev(struct device *a, struct device *b)
+{
+	return 0;
+}
 #endif /* !CONFIG_PM_SLEEP */
 
 /* How to reorder dpm_list after device_move() */

Re: [PATCH 2/2] PM: Fix potential issue with failing asynchronous suspend

[Greg KH]

On Mon, Sep 20, 2010 at 08:00:44PM +0200, Rafael J. Wysocki wrote:
> From: Rafael J. Wysocki <rjw@sisk.pl>
> Subject: PM: Fix potential issue with failing asynchronous suspend
> 
> There is a potential issue with the asynchronous suspend code that
> a device driver suspending asynchronously may not notice that it
> should back off.  There are two failing scenarions, (1) when the
> driver is waiting for a driver suspending synchronously to complete
> and that second driver returns error code, in which case async_error
> won't be set and the waiting driver will continue suspending and (2)
> after the driver has called device_pm_wait_for_dev() and the waited
> for driver returns error code, in which case the caller of
> device_pm_wait_for_dev() will not know that there was an error and
> will continue suspending.
> 
> To fix this issue make __device_suspend() set async_error, so
> async_suspend() doesn't need to set it any more, and make
> device_pm_wait_for_dev() return async_error, so that its callers
> can check whether or not they should continue suspending.
> 
> No more changes are necessary, since device_pm_wait_for_dev() in
> not used by any drivers' suspend routines.
> 
> Reported-by: Colin Cross <ccross@android.com>
> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

Acked-by: Greg Kroah-Hartman <gregkh@suse.de>

Re: [PATCH 2/2] PM: Fix potential issue with failing asynchronous suspend

[Greg KH]

On Mon, Sep 20, 2010 at 08:00:44PM +0200, Rafael J. Wysocki wrote:
> From: Rafael J. Wysocki <rjw@sisk.pl>
> Subject: PM: Fix potential issue with failing asynchronous suspend
> 
> There is a potential issue with the asynchronous suspend code that
> a device driver suspending asynchronously may not notice that it
> should back off.  There are two failing scenarions, (1) when the
> driver is waiting for a driver suspending synchronously to complete
> and that second driver returns error code, in which case async_error
> won't be set and the waiting driver will continue suspending and (2)
> after the driver has called device_pm_wait_for_dev() and the waited
> for driver returns error code, in which case the caller of
> device_pm_wait_for_dev() will not know that there was an error and
> will continue suspending.
> 
> To fix this issue make __device_suspend() set async_error, so
> async_suspend() doesn't need to set it any more, and make
> device_pm_wait_for_dev() return async_error, so that its callers
> can check whether or not they should continue suspending.
> 
> No more changes are necessary, since device_pm_wait_for_dev() in
> not used by any drivers' suspend routines.
> 
> Reported-by: Colin Cross <ccross@android.com>
> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

Acked-by: Greg Kroah-Hartman <gregkh@suse.de>

Re: [PATCH 0/2] PM: Wakeup sources and async suspend error path bug fix

[Rafael J. Wysocki]

On Monday, September 20, 2010, Rafael J. Wysocki wrote:
> Hi,
> 
> The following two patches are ready to go into linux-next from my point of
> view, so please let me know if there are any objections:
> 
> [1/2] - PM / Wakeup: Introduce wakeup source objects and event statistics (v3)
> 
> [2/2] - PM: Fix potential issue with failing asynchronous suspend

Due to the apparent lack of objections I applied the patches from this series
to suspend-2.6/linux-next.

Thanks,
Rafael

Re: [PATCH 0/2] PM: Wakeup sources and async suspend error path bug fix

[Rafael J. Wysocki]

On Monday, September 20, 2010, Rafael J. Wysocki wrote:
> Hi,
> 
> The following two patches are ready to go into linux-next from my point of
> view, so please let me know if there are any objections:
> 
> [1/2] - PM / Wakeup: Introduce wakeup source objects and event statistics (v3)
> 
> [2/2] - PM: Fix potential issue with failing asynchronous suspend

Due to the apparent lack of objections I applied the patches from this series
to suspend-2.6/linux-next.

Thanks,
Rafael

Re: [PATCH 0/2] PM: Wakeup sources and async suspend error path bug fix

[mark gross]

On Mon, Sep 20, 2010 at 07:57:40PM +0200, Rafael J. Wysocki wrote:
> Hi,
> 
> The following two patches are ready to go into linux-next from my point of
> view, so please let me know if there are any objections:
> 
> [1/2] - PM / Wakeup: Introduce wakeup source objects and event statistics (v3)
> 
> [2/2] - PM: Fix potential issue with failing asynchronous suspend
> 
> Thanks,
> Rafael

Sorry for the late response but, what user feed back will this provide
to the OS stack looking to put the system in a low power state?

There are 2 cases I can think of:
1) system wakes from an event that user mode needs to handle (i.e. key
press or phone ring or alarm events)
2) system wakes (or more likely, is blocked from suspending) by a
kernel critical section, say if USB-OTG is connected.

When wake's are of the type 1, then the power manager service could
simply wait for a user mode wake lock be taken and released from the
usermode before re-attempting to suspend.

When the wakes are of type 2, a power manager service thread would need
to do a select on a system file and be woken up to re-try the suspend
after the suspend-blocking is no longer needed.

Do you think I should cobble together an android PM driver that plugs
into your code to expose an ABI for the 2 cases listed above?

Also, with this do we want to revisit a pm_qos class for "active"
systems?  Or do you think thats redundant now?

--mark

Re: [linux-pm] [PATCH 0/2] PM: Wakeup sources and async suspend error path bug fix

[mark gross]

On Mon, Sep 20, 2010 at 07:57:40PM +0200, Rafael J. Wysocki wrote:
> Hi,
> 
> The following two patches are ready to go into linux-next from my point of
> view, so please let me know if there are any objections:
> 
> [1/2] - PM / Wakeup: Introduce wakeup source objects and event statistics (v3)
> 
> [2/2] - PM: Fix potential issue with failing asynchronous suspend
> 
> Thanks,
> Rafael

Sorry for the late response but, what user feed back will this provide
to the OS stack looking to put the system in a low power state?

There are 2 cases I can think of:
1) system wakes from an event that user mode needs to handle (i.e. key
press or phone ring or alarm events)
2) system wakes (or more likely, is blocked from suspending) by a
kernel critical section, say if USB-OTG is connected.

When wake's are of the type 1, then the power manager service could
simply wait for a user mode wake lock be taken and released from the
usermode before re-attempting to suspend.

When the wakes are of type 2, a power manager service thread would need
to do a select on a system file and be woken up to re-try the suspend
after the suspend-blocking is no longer needed.

Do you think I should cobble together an android PM driver that plugs
into your code to expose an ABI for the 2 cases listed above?

Also, with this do we want to revisit a pm_qos class for "active"
systems?  Or do you think thats redundant now?

--mark

Re: [PATCH 0/2] PM: Wakeup sources and async suspend error path bug fix

[Rafael J. Wysocki]

On Monday, October 04, 2010, mark gross wrote:
> On Mon, Sep 20, 2010 at 07:57:40PM +0200, Rafael J. Wysocki wrote:
> > Hi,
> > 
> > The following two patches are ready to go into linux-next from my point of
> > view, so please let me know if there are any objections:
> > 
> > [1/2] - PM / Wakeup: Introduce wakeup source objects and event statistics (v3)
> > 
> > [2/2] - PM: Fix potential issue with failing asynchronous suspend
> > 
> > Thanks,
> > Rafael
> 
> Sorry for the late response but, what user feed back will this provide
> to the OS stack looking to put the system in a low power state?
> 
> There are 2 cases I can think of:
> 1) system wakes from an event that user mode needs to handle (i.e. key
> press or phone ring or alarm events)
> 2) system wakes (or more likely, is blocked from suspending) by a
> kernel critical section, say if USB-OTG is connected.
> 
> When wake's are of the type 1, then the power manager service could
> simply wait for a user mode wake lock be taken and released from the
> usermode before re-attempting to suspend.
> 
> When the wakes are of type 2, a power manager service thread would need
> to do a select on a system file and be woken up to re-try the suspend
> after the suspend-blocking is no longer needed.

IMO it is more convenient to implement that in a different way, but
generally I think you're right.

> Do you think I should cobble together an android PM driver that plugs
> into your code to expose an ABI for the 2 cases listed above?

Well, I'm not sure if I understand correctly, can you elaborate a bit, please?

> Also, with this do we want to revisit a pm_qos class for "active"
> systems?  Or do you think thats redundant now?

I don't really think the pm_qos for "active" systems is really necessary at
this point.

Thanks,
Rafael

Re: [linux-pm] [PATCH 0/2] PM: Wakeup sources and async suspend error path bug fix

[Rafael J. Wysocki]

On Monday, October 04, 2010, mark gross wrote:
> On Mon, Sep 20, 2010 at 07:57:40PM +0200, Rafael J. Wysocki wrote:
> > Hi,
> > 
> > The following two patches are ready to go into linux-next from my point of
> > view, so please let me know if there are any objections:
> > 
> > [1/2] - PM / Wakeup: Introduce wakeup source objects and event statistics (v3)
> > 
> > [2/2] - PM: Fix potential issue with failing asynchronous suspend
> > 
> > Thanks,
> > Rafael
> 
> Sorry for the late response but, what user feed back will this provide
> to the OS stack looking to put the system in a low power state?
> 
> There are 2 cases I can think of:
> 1) system wakes from an event that user mode needs to handle (i.e. key
> press or phone ring or alarm events)
> 2) system wakes (or more likely, is blocked from suspending) by a
> kernel critical section, say if USB-OTG is connected.
> 
> When wake's are of the type 1, then the power manager service could
> simply wait for a user mode wake lock be taken and released from the
> usermode before re-attempting to suspend.
> 
> When the wakes are of type 2, a power manager service thread would need
> to do a select on a system file and be woken up to re-try the suspend
> after the suspend-blocking is no longer needed.

IMO it is more convenient to implement that in a different way, but
generally I think you're right.

> Do you think I should cobble together an android PM driver that plugs
> into your code to expose an ABI for the 2 cases listed above?

Well, I'm not sure if I understand correctly, can you elaborate a bit, please?

> Also, with this do we want to revisit a pm_qos class for "active"
> systems?  Or do you think thats redundant now?

I don't really think the pm_qos for "active" systems is really necessary at
this point.

Thanks,
Rafael

Re: [PATCH 0/2] PM: Wakeup sources and async suspend error path bug fix

[mark gross]

On Mon, Oct 04, 2010 at 01:04:09AM +0200, Rafael J. Wysocki wrote:
> On Monday, October 04, 2010, mark gross wrote:
> > On Mon, Sep 20, 2010 at 07:57:40PM +0200, Rafael J. Wysocki wrote:
> > > Hi,
> > > 
> > > The following two patches are ready to go into linux-next from my point of
> > > view, so please let me know if there are any objections:
> > > 
> > > [1/2] - PM / Wakeup: Introduce wakeup source objects and event statistics (v3)
> > > 
> > > [2/2] - PM: Fix potential issue with failing asynchronous suspend
> > > 
> > > Thanks,
> > > Rafael
> > 
> > Sorry for the late response but, what user feed back will this provide
> > to the OS stack looking to put the system in a low power state?
> > 
> > There are 2 cases I can think of:
> > 1) system wakes from an event that user mode needs to handle (i.e. key
> > press or phone ring or alarm events)
> > 2) system wakes (or more likely, is blocked from suspending) by a
> > kernel critical section, say if USB-OTG is connected.
> > 
> > When wake's are of the type 1, then the power manager service could
> > simply wait for a user mode wake lock be taken and released from the
> > usermode before re-attempting to suspend.
> > 
> > When the wakes are of type 2, a power manager service thread would need
> > to do a select on a system file and be woken up to re-try the suspend
> > after the suspend-blocking is no longer needed.
> 
> IMO it is more convenient to implement that in a different way, but
> generally I think you're right.
> 
> > Do you think I should cobble together an android PM driver that plugs
> > into your code to expose an ABI for the 2 cases listed above?
> 
> Well, I'm not sure if I understand correctly, can you elaborate a bit, please?

Well, before I saw your patch I was thinking about implementing an
Android PM driver that would request a pm_qos active request that would
be notified and interface with your wake event code.  It would also
expose a misc /dev/susped_blocked node that would be signaled when the
pm_qos active request went to zero.

Now I'm sort of making things up as I go but, some sort of non-poling
mechanism to re-attempt the suspend, for type 2, is needed but I'm not
sure where to put it now.

Also, we may want to think about registering events that user mode will
handle, and all others are treated as type 2 events.


> > Also, with this do we want to revisit a pm_qos class for "active"
> > systems?  Or do you think thats redundant now?
> 
> I don't really think the pm_qos for "active" systems is really necessary at
> this point.
>

I'm still studying the patch but, you are likely right.  I need to look
at how much overhead changing the suspend blocking/unblocking is
handled.  I expect that some drivers will be hitting it on hot code
paths.

--mark

> Thanks,
> Rafael

Re: [linux-pm] [PATCH 0/2] PM: Wakeup sources and async suspend error path bug fix

[mark gross]

On Mon, Oct 04, 2010 at 01:04:09AM +0200, Rafael J. Wysocki wrote:
> On Monday, October 04, 2010, mark gross wrote:
> > On Mon, Sep 20, 2010 at 07:57:40PM +0200, Rafael J. Wysocki wrote:
> > > Hi,
> > > 
> > > The following two patches are ready to go into linux-next from my point of
> > > view, so please let me know if there are any objections:
> > > 
> > > [1/2] - PM / Wakeup: Introduce wakeup source objects and event statistics (v3)
> > > 
> > > [2/2] - PM: Fix potential issue with failing asynchronous suspend
> > > 
> > > Thanks,
> > > Rafael
> > 
> > Sorry for the late response but, what user feed back will this provide
> > to the OS stack looking to put the system in a low power state?
> > 
> > There are 2 cases I can think of:
> > 1) system wakes from an event that user mode needs to handle (i.e. key
> > press or phone ring or alarm events)
> > 2) system wakes (or more likely, is blocked from suspending) by a
> > kernel critical section, say if USB-OTG is connected.
> > 
> > When wake's are of the type 1, then the power manager service could
> > simply wait for a user mode wake lock be taken and released from the
> > usermode before re-attempting to suspend.
> > 
> > When the wakes are of type 2, a power manager service thread would need
> > to do a select on a system file and be woken up to re-try the suspend
> > after the suspend-blocking is no longer needed.
> 
> IMO it is more convenient to implement that in a different way, but
> generally I think you're right.
> 
> > Do you think I should cobble together an android PM driver that plugs
> > into your code to expose an ABI for the 2 cases listed above?
> 
> Well, I'm not sure if I understand correctly, can you elaborate a bit, please?

Well, before I saw your patch I was thinking about implementing an
Android PM driver that would request a pm_qos active request that would
be notified and interface with your wake event code.  It would also
expose a misc /dev/susped_blocked node that would be signaled when the
pm_qos active request went to zero.

Now I'm sort of making things up as I go but, some sort of non-poling
mechanism to re-attempt the suspend, for type 2, is needed but I'm not
sure where to put it now.

Also, we may want to think about registering events that user mode will
handle, and all others are treated as type 2 events.


> > Also, with this do we want to revisit a pm_qos class for "active"
> > systems?  Or do you think thats redundant now?
> 
> I don't really think the pm_qos for "active" systems is really necessary at
> this point.
>

I'm still studying the patch but, you are likely right.  I need to look
at how much overhead changing the suspend blocking/unblocking is
handled.  I expect that some drivers will be hitting it on hot code
paths.

--mark

> Thanks,
> Rafael

Re: [PATCH 0/2] PM: Wakeup sources and async suspend error path bug fix

[Rafael J. Wysocki]

On Monday, October 04, 2010, mark gross wrote:
> On Mon, Oct 04, 2010 at 01:04:09AM +0200, Rafael J. Wysocki wrote:
> > On Monday, October 04, 2010, mark gross wrote:
> > > On Mon, Sep 20, 2010 at 07:57:40PM +0200, Rafael J. Wysocki wrote:
> > > > Hi,
> > > > 
> > > > The following two patches are ready to go into linux-next from my point of
> > > > view, so please let me know if there are any objections:
> > > > 
> > > > [1/2] - PM / Wakeup: Introduce wakeup source objects and event statistics (v3)
> > > > 
> > > > [2/2] - PM: Fix potential issue with failing asynchronous suspend
> > > > 
> > > > Thanks,
> > > > Rafael
> > > 
> > > Sorry for the late response but, what user feed back will this provide
> > > to the OS stack looking to put the system in a low power state?
> > > 
> > > There are 2 cases I can think of:
> > > 1) system wakes from an event that user mode needs to handle (i.e. key
> > > press or phone ring or alarm events)
> > > 2) system wakes (or more likely, is blocked from suspending) by a
> > > kernel critical section, say if USB-OTG is connected.
> > > 
> > > When wake's are of the type 1, then the power manager service could
> > > simply wait for a user mode wake lock be taken and released from the
> > > usermode before re-attempting to suspend.
> > > 
> > > When the wakes are of type 2, a power manager service thread would need
> > > to do a select on a system file and be woken up to re-try the suspend
> > > after the suspend-blocking is no longer needed.
> > 
> > IMO it is more convenient to implement that in a different way, but
> > generally I think you're right.
> > 
> > > Do you think I should cobble together an android PM driver that plugs
> > > into your code to expose an ABI for the 2 cases listed above?
> > 
> > Well, I'm not sure if I understand correctly, can you elaborate a bit, please?
> 
> Well, before I saw your patch I was thinking about implementing an
> Android PM driver that would request a pm_qos active request that would
> be notified and interface with your wake event code.  It would also
> expose a misc /dev/susped_blocked node that would be signaled when the
> pm_qos active request went to zero.
> 
> Now I'm sort of making things up as I go but, some sort of non-poling
> mechanism to re-attempt the suspend, for type 2, is needed but I'm not
> sure where to put it now.

There always will be some kind of "polling" involved, because some operations
will have to be retried, but that should still be fine as long as the power
manager puts itself to sleep whenever it sees that suspend is "blocked".

Reading from /sys/power/wakeup_count blocks until events_in_progress is zero
and there should be some IPC between the power manager and the user space
tasks allowed to "block suspend" that will put the power manager to sleep
until it's OK to try suspending.

> Also, we may want to think about registering events that user mode will
> handle, and all others are treated as type 2 events.
> 
> 
> > > Also, with this do we want to revisit a pm_qos class for "active"
> > > systems?  Or do you think thats redundant now?
> > 
> > I don't really think the pm_qos for "active" systems is really necessary at
> > this point.
> >
> 
> I'm still studying the patch but, you are likely right.  I need to look
> at how much overhead changing the suspend blocking/unblocking is
> handled.  I expect that some drivers will be hitting it on hot code
> paths.

That involves taking two spinlocks that shouldn't be contended for
(one in struct  dev_pm_info and one in struct wakeup_source) and one (for
blocking) or two (for unblocking) atomic variables.   For unblocking there
also is a spinlock to take in del_timer() if the timer is pending, but that
only happens if there's a timeout.

Thanks,
Rafael

Re: [linux-pm] [PATCH 0/2] PM: Wakeup sources and async suspend error path bug fix

[Rafael J. Wysocki]

On Monday, October 04, 2010, mark gross wrote:
> On Mon, Oct 04, 2010 at 01:04:09AM +0200, Rafael J. Wysocki wrote:
> > On Monday, October 04, 2010, mark gross wrote:
> > > On Mon, Sep 20, 2010 at 07:57:40PM +0200, Rafael J. Wysocki wrote:
> > > > Hi,
> > > > 
> > > > The following two patches are ready to go into linux-next from my point of
> > > > view, so please let me know if there are any objections:
> > > > 
> > > > [1/2] - PM / Wakeup: Introduce wakeup source objects and event statistics (v3)
> > > > 
> > > > [2/2] - PM: Fix potential issue with failing asynchronous suspend
> > > > 
> > > > Thanks,
> > > > Rafael
> > > 
> > > Sorry for the late response but, what user feed back will this provide
> > > to the OS stack looking to put the system in a low power state?
> > > 
> > > There are 2 cases I can think of:
> > > 1) system wakes from an event that user mode needs to handle (i.e. key
> > > press or phone ring or alarm events)
> > > 2) system wakes (or more likely, is blocked from suspending) by a
> > > kernel critical section, say if USB-OTG is connected.
> > > 
> > > When wake's are of the type 1, then the power manager service could
> > > simply wait for a user mode wake lock be taken and released from the
> > > usermode before re-attempting to suspend.
> > > 
> > > When the wakes are of type 2, a power manager service thread would need
> > > to do a select on a system file and be woken up to re-try the suspend
> > > after the suspend-blocking is no longer needed.
> > 
> > IMO it is more convenient to implement that in a different way, but
> > generally I think you're right.
> > 
> > > Do you think I should cobble together an android PM driver that plugs
> > > into your code to expose an ABI for the 2 cases listed above?
> > 
> > Well, I'm not sure if I understand correctly, can you elaborate a bit, please?
> 
> Well, before I saw your patch I was thinking about implementing an
> Android PM driver that would request a pm_qos active request that would
> be notified and interface with your wake event code.  It would also
> expose a misc /dev/susped_blocked node that would be signaled when the
> pm_qos active request went to zero.
> 
> Now I'm sort of making things up as I go but, some sort of non-poling
> mechanism to re-attempt the suspend, for type 2, is needed but I'm not
> sure where to put it now.

There always will be some kind of "polling" involved, because some operations
will have to be retried, but that should still be fine as long as the power
manager puts itself to sleep whenever it sees that suspend is "blocked".

Reading from /sys/power/wakeup_count blocks until events_in_progress is zero
and there should be some IPC between the power manager and the user space
tasks allowed to "block suspend" that will put the power manager to sleep
until it's OK to try suspending.

> Also, we may want to think about registering events that user mode will
> handle, and all others are treated as type 2 events.
> 
> 
> > > Also, with this do we want to revisit a pm_qos class for "active"
> > > systems?  Or do you think thats redundant now?
> > 
> > I don't really think the pm_qos for "active" systems is really necessary at
> > this point.
> >
> 
> I'm still studying the patch but, you are likely right.  I need to look
> at how much overhead changing the suspend blocking/unblocking is
> handled.  I expect that some drivers will be hitting it on hot code
> paths.

That involves taking two spinlocks that shouldn't be contended for
(one in struct  dev_pm_info and one in struct wakeup_source) and one (for
blocking) or two (for unblocking) atomic variables.   For unblocking there
also is a spinlock to take in del_timer() if the timer is pending, but that
only happens if there's a timeout.

Thanks,
Rafael