Merge branch 'pm-sleep' into acpi-battery

Documentation/ABI/testing/sysfs-power

@@ -7,19 +7,30 @@ Description:
 		subsystem.
 
 What:		/sys/power/state
-Date:		August 2006
+Date:		May 2014
 Contact:	Rafael J. Wysocki <rjw@rjwysocki.net>
 Description:
-		The /sys/power/state file controls the system power state.
-		Reading from this file returns what states are supported,
-		which is hard-coded to 'freeze' (Low-Power Idle), 'standby'
-		(Power-On Suspend), 'mem' (Suspend-to-RAM), and 'disk'
-		(Suspend-to-Disk).
+		The /sys/power/state file controls system sleep states.
+		Reading from this file returns the available sleep state
+		labels, which may be "mem", "standby", "freeze" and "disk"
+		(hibernation).  The meanings of the first three labels depend on
+		the relative_sleep_states command line argument as follows:
+		 1) relative_sleep_states = 1
+		    "mem", "standby", "freeze" represent non-hibernation sleep
+		    states from the deepest ("mem", always present) to the
+		    shallowest ("freeze").  "standby" and "freeze" may or may
+		    not be present depending on the capabilities of the
+		    platform.  "freeze" can only be present if "standby" is
+		    present.
+		 2) relative_sleep_states = 0 (default)
+		    "mem" - "suspend-to-RAM", present if supported.
+		    "standby" - "power-on suspend", present if supported.
+		    "freeze" - "suspend-to-idle", always present.
 
 		Writing to this file one of these strings causes the system to
-		transition into that state. Please see the file
-		Documentation/power/states.txt for a description of each of
-		these states.
+		transition into the corresponding state, if available.  See
+		Documentation/power/states.txt for a description of what
+		"suspend-to-RAM", "power-on suspend" and "suspend-to-idle" mean.
 
 What:		/sys/power/disk
 Date:		September 2006

Documentation/kernel-parameters.txt

@@ -2889,6 +2889,13 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
 			[KNL, SMP] Set scheduler's default relax_domain_level.
 			See Documentation/cgroups/cpusets.txt.
 
+	relative_sleep_states=
+			[SUSPEND] Use sleep state labeling where the deepest
+			state available other than hibernation is always "mem".
+			Format: { "0" | "1" }
+			0 -- Traditional sleep state labels.
+			1 -- Relative sleep state labels.
+
 	reserve=	[KNL,BUGS] Force the kernel to ignore some iomem area
 
 	reservetop=	[X86-32]

Documentation/power/devices.txt

@@ -2,6 +2,7 @@ Device Power Management
 
 Copyright (c) 2010-2011 Rafael J. Wysocki <rjw@sisk.pl>, Novell Inc.
 Copyright (c) 2010 Alan Stern <stern@rowland.harvard.edu>
+Copyright (c) 2014 Intel Corp., Rafael J. Wysocki <rafael.j.wysocki@intel.com>
 
 
 Most of the code in Linux is device drivers, so most of the Linux power
@@ -326,6 +327,20 @@ the phases are:
 	driver in some way for the upcoming system power transition, but it
 	should not put the device into a low-power state.
 
+	For devices supporting runtime power management, the return value of the
+	prepare callback can be used to indicate to the PM core that it may
+	safely leave the device in runtime suspend (if runtime-suspended
+	already), provided that all of the device's descendants are also left in
+	runtime suspend.  Namely, if the prepare callback returns a positive
+	number and that happens for all of the descendants of the device too,
+	and all of them (including the device itself) are runtime-suspended, the
+	PM core will skip the suspend, suspend_late and	suspend_noirq suspend
+	phases as well as the resume_noirq, resume_early and resume phases of
+	the following system resume for all of these devices.	In that case,
+	the complete callback will be called directly after the prepare callback
+	and is entirely responsible for bringing the device back to the
+	functional state as appropriate.
+
     2.	The suspend methods should quiesce the device to stop it from performing
 	I/O.  They also may save the device registers and put it into the
 	appropriate low-power state, depending on the bus type the device is on,
@@ -400,12 +415,23 @@ When resuming from freeze, standby or memory sleep, the phases are:
 	the resume callbacks occur; it's not necessary to wait until the
 	complete phase.
 
+	Moreover, if the preceding prepare callback returned a positive number,
+	the device may have been left in runtime suspend throughout the whole
+	system suspend and resume (the suspend, suspend_late, suspend_noirq
+	phases of system suspend and the resume_noirq, resume_early, resume
+	phases of system resume may have been skipped for it).  In that case,
+	the complete callback is entirely responsible for bringing the device
+	back to the functional state after system suspend if necessary.  [For
+	example, it may need to queue up a runtime resume request for the device
+	for this purpose.]  To check if that is the case, the complete callback
+	can consult the device's power.direct_complete flag.  Namely, if that
+	flag is set when the complete callback is being run, it has been called
+	directly after the preceding prepare and special action may be required
+	to make the device work correctly afterward.
+
 At the end of these phases, drivers should be as functional as they were before
 suspending: I/O can be performed using DMA and IRQs, and the relevant clocks are
-gated on.  Even if the device was in a low-power state before the system sleep
-because of runtime power management, afterwards it should be back in its
-full-power state.  There are multiple reasons why it's best to do this; they are
-discussed in more detail in Documentation/power/runtime_pm.txt.
+gated on.
 
 However, the details here may again be platform-specific.  For example,
 some systems support multiple "run" states, and the mode in effect at

Documentation/power/runtime_pm.txt

@@ -2,6 +2,7 @@ Runtime Power Management Framework for I/O Devices
 
 (C) 2009-2011 Rafael J. Wysocki <rjw@sisk.pl>, Novell Inc.
 (C) 2010 Alan Stern <stern@rowland.harvard.edu>
+(C) 2014 Intel Corp., Rafael J. Wysocki <rafael.j.wysocki@intel.com>
 
 1. Introduction
 
@@ -444,6 +445,10 @@ drivers/base/power/runtime.c and include/linux/pm_runtime.h:
   bool pm_runtime_status_suspended(struct device *dev);
     - return true if the device's runtime PM status is 'suspended'
 
+  bool pm_runtime_suspended_if_enabled(struct device *dev);
+    - return true if the device's runtime PM status is 'suspended' and its
+      'power.disable_depth' field is equal to 1
+
   void pm_runtime_allow(struct device *dev);
     - set the power.runtime_auto flag for the device and decrease its usage
       counter (used by the /sys/devices/.../power/control interface to
@@ -644,6 +649,18 @@ place (in particular, if the system is not waking up from hibernation), it may
 be more efficient to leave the devices that had been suspended before the system
 suspend began in the suspended state.
 
+To this end, the PM core provides a mechanism allowing some coordination between
+different levels of device hierarchy.  Namely, if a system suspend .prepare()
+callback returns a positive number for a device, that indicates to the PM core
+that the device appears to be runtime-suspended and its state is fine, so it
+may be left in runtime suspend provided that all of its descendants are also
+left in runtime suspend.  If that happens, the PM core will not execute any
+system suspend and resume callbacks for all of those devices, except for the
+complete callback, which is then entirely responsible for handling the device
+as appropriate.  This only applies to system suspend transitions that are not
+related to hibernation (see Documentation/power/devices.txt for more
+information).
+
 The PM core does its best to reduce the probability of race conditions between
 the runtime PM and system suspend/resume (and hibernation) callbacks by carrying
 out the following operations:

Documentation/power/states.txt

@@ -1,62 +1,87 @@
+System Power Management Sleep States
 
-System Power Management States
+(C) 2014 Intel Corp., Rafael J. Wysocki <rafael.j.wysocki@intel.com>
 
+The kernel supports up to four system sleep states generically, although three
+of them depend on the platform support code to implement the low-level details
+for each state.
 
-The kernel supports four power management states generically, though
-one is generic and the other three are dependent on platform support
-code to implement the low-level details for each state.
-This file describes each state, what they are
-commonly called, what ACPI state they map to, and what string to write
-to /sys/power/state to enter that state
+The states are represented by strings that can be read or written to the
+/sys/power/state file.  Those strings may be "mem", "standby", "freeze" and
+"disk", where the last one always represents hibernation (Suspend-To-Disk) and
+the meaning of the remaining ones depends on the relative_sleep_states command
+line argument.
 
-state:		Freeze / Low-Power Idle
+For relative_sleep_states=1, the strings "mem", "standby" and "freeze" label the
+available non-hibernation sleep states from the deepest to the shallowest,
+respectively.  In that case, "mem" is always present in /sys/power/state,
+because there is at least one non-hibernation sleep state in every system.  If
+the given system supports two non-hibernation sleep states, "standby" is present
+in /sys/power/state in addition to "mem".  If the system supports three
+non-hibernation sleep states, "freeze" will be present in /sys/power/state in
+addition to "mem" and "standby".
+
+For relative_sleep_states=0, which is the default, the following descriptions
+apply.
+
+state:		Suspend-To-Idle
 ACPI state:	S0
-String:		"freeze"
+Label:		"freeze"
 
-This state is a generic, pure software, light-weight, low-power state.
-It allows more energy to be saved relative to idle by freezing user
+This state is a generic, pure software, light-weight, system sleep state.
+It allows more energy to be saved relative to runtime idle by freezing user
 space and putting all I/O devices into low-power states (possibly
 lower-power than available at run time), such that the processors can
 spend more time in their idle states.
-This state can be used for platforms without Standby/Suspend-to-RAM
+
+This state can be used for platforms without Power-On Suspend/Suspend-to-RAM
 support, or it can be used in addition to Suspend-to-RAM (memory sleep)
-to provide reduced resume latency.
+to provide reduced resume latency.  It is always supported.
 
 
 State:		Standby / Power-On Suspend
 ACPI State:	S1
-String:		"standby"
+Label:		"standby"
 
-This state offers minimal, though real, power savings, while providing
-a very low-latency transition back to a working system. No operating
-state is lost (the CPU retains power), so the system easily starts up
+This state, if supported, offers moderate, though real, power savings, while
+providing a relatively low-latency transition back to a working system.  No
+operating state is lost (the CPU retains power), so the system easily starts up
 again where it left off. 
 
-We try to put devices in a low-power state equivalent to D1, which
-also offers low power savings, but low resume latency. Not all devices
-support D1, and those that don't are left on. 
+In addition to freezing user space and putting all I/O devices into low-power
+states, which is done for Suspend-To-Idle too, nonboot CPUs are taken offline
+and all low-level system functions are suspended during transitions into this
+state.  For this reason, it should allow more energy to be saved relative to
+Suspend-To-Idle, but the resume latency will generally be greater than for that
+state.
 
 
 State:		Suspend-to-RAM
 ACPI State:	S3
-String:		"mem"
+Label:		"mem"
 
-This state offers significant power savings as everything in the
-system is put into a low-power state, except for memory, which is
-placed in self-refresh mode to retain its contents. 
+This state, if supported, offers significant power savings as everything in the
+system is put into a low-power state, except for memory, which should be placed
+into the self-refresh mode to retain its contents.  All of the steps carried out
+when entering Power-On Suspend are also carried out during transitions to STR.
+Additional operations may take place depending on the platform capabilities.  In
+particular, on ACPI systems the kernel passes control to the BIOS (platform
+firmware) as the last step during STR transitions and that usually results in
+powering down some more low-level components that aren't directly controlled by
+the kernel.
 
-System and device state is saved and kept in memory. All devices are
-suspended and put into D3. In many cases, all peripheral buses lose
-power when entering STR, so devices must be able to handle the
-transition back to the On state. 
+System and device state is saved and kept in memory.  All devices are suspended
+and put into low-power states.  In many cases, all peripheral buses lose power
+when entering STR, so devices must be able to handle the transition back to the
+"on" state.
 
-For at least ACPI, STR requires some minimal boot-strapping code to
-resume the system from STR. This may be true on other platforms. 
+For at least ACPI, STR requires some minimal boot-strapping code to resume the
+system from it.  This may be the case on other platforms too.
 
 
 State:		Suspend-to-disk
 ACPI State:	S4
-String:		"disk"
+Label:		"disk"
 
 This state offers the greatest power savings, and can be used even in
 the absence of low-level platform support for power management. This

Documentation/power/swsusp.txt

@@ -220,7 +220,10 @@ Q: After resuming, system is paging heavily, leading to very bad interactivity.
 
 A: Try running
 
-cat `cat /proc/[0-9]*/maps | grep / | sed 's:.* /:/:' | sort -u` > /dev/null
+cat /proc/[0-9]*/maps | grep / | sed 's:.* /:/:' | sort -u | while read file
+do
+  test -f "$file" && cat "$file" > /dev/null
+done
 
 after resume. swapoff -a; swapon -a may also be useful.
 

drivers/base/power/main.c

@@ -479,7 +479,7 @@ static int device_resume_noirq(struct device *dev, pm_message_t state, bool asyn
 	TRACE_DEVICE(dev);
 	TRACE_RESUME(0);
 
-	if (dev->power.syscore)
+	if (dev->power.syscore || dev->power.direct_complete)
 		goto Out;
 
 	if (!dev->power.is_noirq_suspended)
@@ -605,7 +605,7 @@ static int device_resume_early(struct device *dev, pm_message_t state, bool asyn
 	TRACE_DEVICE(dev);
 	TRACE_RESUME(0);
 
-	if (dev->power.syscore)
+	if (dev->power.syscore || dev->power.direct_complete)
 		goto Out;
 
 	if (!dev->power.is_late_suspended)
@@ -735,6 +735,12 @@ static int device_resume(struct device *dev, pm_message_t state, bool async)
 	if (dev->power.syscore)
 		goto Complete;
 
+	if (dev->power.direct_complete) {
+		/* Match the pm_runtime_disable() in __device_suspend(). */
+		pm_runtime_enable(dev);
+		goto Complete;
+	}
+
 	dpm_wait(dev->parent, async);
 	dpm_watchdog_set(&wd, dev);
 	device_lock(dev);
@@ -1007,7 +1013,7 @@ static int __device_suspend_noirq(struct device *dev, pm_message_t state, bool a
 		goto Complete;
 	}
 
-	if (dev->power.syscore)
+	if (dev->power.syscore || dev->power.direct_complete)
 		goto Complete;
 
 	dpm_wait_for_children(dev, async);
@@ -1146,7 +1152,7 @@ static int __device_suspend_late(struct device *dev, pm_message_t state, bool as
 		goto Complete;
 	}
 
-	if (dev->power.syscore)
+	if (dev->power.syscore || dev->power.direct_complete)
 		goto Complete;
 
 	dpm_wait_for_children(dev, async);
@@ -1332,6 +1338,17 @@ static int __device_suspend(struct device *dev, pm_message_t state, bool async)
 	if (dev->power.syscore)
 		goto Complete;
 
+	if (dev->power.direct_complete) {
+		if (pm_runtime_status_suspended(dev)) {
+			pm_runtime_disable(dev);
+			if (pm_runtime_suspended_if_enabled(dev))
+				goto Complete;
+
+			pm_runtime_enable(dev);
+		}
+		dev->power.direct_complete = false;
+	}
+
 	dpm_watchdog_set(&wd, dev);
 	device_lock(dev);
 
@@ -1382,10 +1399,19 @@ static int __device_suspend(struct device *dev, pm_message_t state, bool async)
 
  End:
 	if (!error) {
+		struct device *parent = dev->parent;
+
 		dev->power.is_suspended = true;
-		if (dev->power.wakeup_path
-		    && dev->parent && !dev->parent->power.ignore_children)
-			dev->parent->power.wakeup_path = true;
+		if (parent) {
+			spin_lock_irq(&parent->power.lock);
+
+			dev->parent->power.direct_complete = false;
+			if (dev->power.wakeup_path
+			    && !dev->parent->power.ignore_children)
+				dev->parent->power.wakeup_path = true;
+
+			spin_unlock_irq(&parent->power.lock);
+		}
 	}
 
 	device_unlock(dev);
@@ -1487,7 +1513,7 @@ static int device_prepare(struct device *dev, pm_message_t state)
 {
 	int (*callback)(struct device *) = NULL;
 	char *info = NULL;
-	int error = 0;
+	int ret = 0;
 
 	if (dev->power.syscore)
 		return 0;
@@ -1523,17 +1549,27 @@ static int device_prepare(struct device *dev, pm_message_t state)
 		callback = dev->driver->pm->prepare;
 	}
 
-	if (callback) {
-		error = callback(dev);
-		suspend_report_result(callback, error);
-	}
+	if (callback)
+		ret = callback(dev);
 
 	device_unlock(dev);
 
-	if (error)
+	if (ret < 0) {
+		suspend_report_result(callback, ret);
 		pm_runtime_put(dev);
-
-	return error;
+		return ret;
+	}
+	/*
+	 * A positive return value from ->prepare() means "this device appears
+	 * to be runtime-suspended and its state is fine, so if it really is
+	 * runtime-suspended, you can leave it in that state provided that you
+	 * will do the same thing with all of its descendants".  This only
+	 * applies to suspend transitions, however.
+	 */
+	spin_lock_irq(&dev->power.lock);
+	dev->power.direct_complete = ret > 0 && state.event == PM_EVENT_SUSPEND;
+	spin_unlock_irq(&dev->power.lock);
+	return 0;
 }
 
 /**

drivers/base/power/wakeup.c

@@ -318,10 +318,16 @@ int device_init_wakeup(struct device *dev, bool enable)
 {
 	int ret = 0;
 
+	if (!dev)
+		return -EINVAL;
+
 	if (enable) {
 		device_set_wakeup_capable(dev, true);
 		ret = device_wakeup_enable(dev);
 	} else {
+		if (dev->power.can_wakeup)
+			device_wakeup_disable(dev);
+
 		device_set_wakeup_capable(dev, false);
 	}
 

drivers/cpuidle/cpuidle.c

@@ -32,6 +32,7 @@ LIST_HEAD(cpuidle_detected_devices);
 static int enabled_devices;
 static int off __read_mostly;
 static int initialized __read_mostly;
+static bool use_deepest_state __read_mostly;
 
 int cpuidle_disabled(void)
 {
@@ -65,23 +66,42 @@ int cpuidle_play_dead(void)
 }
 
 /**
- * cpuidle_enabled - check if the cpuidle framework is ready
- * @dev: cpuidle device for this cpu
- * @drv: cpuidle driver for this cpu
+ * cpuidle_use_deepest_state - Enable/disable the "deepest idle" mode.
+ * @enable: Whether enable or disable the feature.
+ *
+ * If the "deepest idle" mode is enabled, cpuidle will ignore the governor and
+ * always use the state with the greatest exit latency (out of the states that
+ * are not disabled).
  *
- * Return 0 on success, otherwise:
- * -NODEV : the cpuidle framework is not available
- * -EBUSY : the cpuidle framework is not initialized
+ * This function can only be called after cpuidle_pause() to avoid races.
  */
-int cpuidle_enabled(struct cpuidle_driver *drv, struct cpuidle_device *dev)
+void cpuidle_use_deepest_state(bool enable)
 {
-	if (off || !initialized)
-		return -ENODEV;
+	use_deepest_state = enable;
+}
 
-	if (!drv || !dev || !dev->enabled)
-		return -EBUSY;
+/**
+ * cpuidle_find_deepest_state - Find the state of the greatest exit latency.
+ * @drv: cpuidle driver for a given CPU.
+ * @dev: cpuidle device for a given CPU.
+ */
+static int cpuidle_find_deepest_state(struct cpuidle_driver *drv,
+				      struct cpuidle_device *dev)
+{
+	unsigned int latency_req = 0;
+	int i, ret = CPUIDLE_DRIVER_STATE_START - 1;
 
-	return 0;
+	for (i = CPUIDLE_DRIVER_STATE_START; i < drv->state_count; i++) {
+		struct cpuidle_state *s = &drv->states[i];
+		struct cpuidle_state_usage *su = &dev->states_usage[i];
+
+		if (s->disabled || su->disable || s->exit_latency <= latency_req)
+			continue;
+
+		latency_req = s->exit_latency;
+		ret = i;
+	}
+	return ret;
 }
 
 /**
@@ -138,6 +158,15 @@ int cpuidle_enter_state(struct cpuidle_device *dev, struct cpuidle_driver *drv,
  */
 int cpuidle_select(struct cpuidle_driver *drv, struct cpuidle_device *dev)
 {
+	if (off || !initialized)
+		return -ENODEV;
+
+	if (!drv || !dev || !dev->enabled)
+		return -EBUSY;
+
+	if (unlikely(use_deepest_state))
+		return cpuidle_find_deepest_state(drv, dev);
+
 	return cpuidle_curr_governor->select(drv, dev);
 }
 
@@ -169,7 +198,7 @@ int cpuidle_enter(struct cpuidle_driver *drv, struct cpuidle_device *dev,
  */
 void cpuidle_reflect(struct cpuidle_device *dev, int index)
 {
-	if (cpuidle_curr_governor->reflect)
+	if (cpuidle_curr_governor->reflect && !unlikely(use_deepest_state))
 		cpuidle_curr_governor->reflect(dev, index);
 }
 

drivers/cpuidle/governors/menu.c

@@ -296,7 +296,7 @@ static int menu_select(struct cpuidle_driver *drv, struct cpuidle_device *dev)
 		data->needs_update = 0;
 	}
 
-	data->last_state_idx = 0;
+	data->last_state_idx = CPUIDLE_DRIVER_STATE_START - 1;
 
 	/* Special case when user has set very strict latency requirement */
 	if (unlikely(latency_req == 0))
@@ -310,13 +310,6 @@ static int menu_select(struct cpuidle_driver *drv, struct cpuidle_device *dev)
 
 	data->bucket = which_bucket(data->next_timer_us);
 
-	/*
-	 * if the correction factor is 0 (eg first time init or cpu hotplug
-	 * etc), we actually want to start out with a unity factor.
-	 */
-	if (data->correction_factor[data->bucket] == 0)
-		data->correction_factor[data->bucket] = RESOLUTION * DECAY;
-
 	/*
 	 * Force the result of multiplication to be 64 bits even if both
 	 * operands are 32 bits.
@@ -466,9 +459,17 @@ static int menu_enable_device(struct cpuidle_driver *drv,
 				struct cpuidle_device *dev)
 {
 	struct menu_device *data = &per_cpu(menu_devices, dev->cpu);
+	int i;
 
 	memset(data, 0, sizeof(struct menu_device));
 
+	/*
+	 * if the correction factor is 0 (eg first time init or cpu hotplug
+	 * etc), we actually want to start out with a unity factor.
+	 */
+	for(i = 0; i < BUCKETS; i++)
+		data->correction_factor[i] = RESOLUTION * DECAY;
+
 	return 0;
 }
 

include/linux/cpuidle.h

@@ -120,8 +120,6 @@ struct cpuidle_driver {
 #ifdef CONFIG_CPU_IDLE
 extern void disable_cpuidle(void);
 
-extern int cpuidle_enabled(struct cpuidle_driver *drv,
-			  struct cpuidle_device *dev);
 extern int cpuidle_select(struct cpuidle_driver *drv,
 			  struct cpuidle_device *dev);
 extern int cpuidle_enter(struct cpuidle_driver *drv,
@@ -145,13 +143,11 @@ extern void cpuidle_resume(void);
 extern int cpuidle_enable_device(struct cpuidle_device *dev);
 extern void cpuidle_disable_device(struct cpuidle_device *dev);
 extern int cpuidle_play_dead(void);
+extern void cpuidle_use_deepest_state(bool enable);
 
 extern struct cpuidle_driver *cpuidle_get_cpu_driver(struct cpuidle_device *dev);
 #else
 static inline void disable_cpuidle(void) { }
-static inline int cpuidle_enabled(struct cpuidle_driver *drv,
-				  struct cpuidle_device *dev)
-{return -ENODEV; }
 static inline int cpuidle_select(struct cpuidle_driver *drv,
 				 struct cpuidle_device *dev)
 {return -ENODEV; }
@@ -180,6 +176,7 @@ static inline int cpuidle_enable_device(struct cpuidle_device *dev)
 {return -ENODEV; }
 static inline void cpuidle_disable_device(struct cpuidle_device *dev) { }
 static inline int cpuidle_play_dead(void) {return -ENODEV; }
+static inline void cpuidle_use_deepest_state(bool enable) {}
 static inline struct cpuidle_driver *cpuidle_get_cpu_driver(
 	struct cpuidle_device *dev) {return NULL; }
 #endif

include/linux/pm.h

@@ -93,13 +93,23 @@ typedef struct pm_message {
  *	been registered) to recover from the race condition.
  *	This method is executed for all kinds of suspend transitions and is
  *	followed by one of the suspend callbacks: @suspend(), @freeze(), or
- *	@poweroff().  The PM core executes subsystem-level @prepare() for all
- *	devices before starting to invoke suspend callbacks for any of them, so
- *	generally devices may be assumed to be functional or to respond to
- *	runtime resume requests while @prepare() is being executed.  However,
- *	device drivers may NOT assume anything about the availability of user
- *	space at that time and it is NOT valid to request firmware from within
- *	@prepare() (it's too late to do that).  It also is NOT valid to allocate
+ *	@poweroff().  If the transition is a suspend to memory or standby (that
+ *	is, not related to hibernation), the return value of @prepare() may be
+ *	used to indicate to the PM core to leave the device in runtime suspend
+ *	if applicable.  Namely, if @prepare() returns a positive number, the PM
+ *	core will understand that as a declaration that the device appears to be
+ *	runtime-suspended and it may be left in that state during the entire
+ *	transition and during the subsequent resume if all of its descendants
+ *	are left in runtime suspend too.  If that happens, @complete() will be
+ *	executed directly after @prepare() and it must ensure the proper
+ *	functioning of the device after the system resume.
+ *	The PM core executes subsystem-level @prepare() for all devices before
+ *	starting to invoke suspend callbacks for any of them, so generally
+ *	devices may be assumed to be functional or to respond to runtime resume
+ *	requests while @prepare() is being executed.  However, device drivers
+ *	may NOT assume anything about the availability of user space at that
+ *	time and it is NOT valid to request firmware from within @prepare()
+ *	(it's too late to do that).  It also is NOT valid to allocate
  *	substantial amounts of memory from @prepare() in the GFP_KERNEL mode.
  *	[To work around these limitations, drivers may register suspend and
  *	hibernation notifiers to be executed before the freezing of tasks.]
@@ -112,7 +122,16 @@ typedef struct pm_message {
  *	of the other devices that the PM core has unsuccessfully attempted to
  *	suspend earlier).
  *	The PM core executes subsystem-level @complete() after it has executed
- *	the appropriate resume callbacks for all devices.
+ *	the appropriate resume callbacks for all devices.  If the corresponding
+ *	@prepare() at the beginning of the suspend transition returned a
+ *	positive number and the device was left in runtime suspend (without
+ *	executing any suspend and resume callbacks for it), @complete() will be
+ *	the only callback executed for the device during resume.  In that case,
+ *	@complete() must be prepared to do whatever is necessary to ensure the
+ *	proper functioning of the device after the system resume.  To this end,
+ *	@complete() can check the power.direct_complete flag of the device to
+ *	learn whether (unset) or not (set) the previous suspend and resume
+ *	callbacks have been executed for it.
  *
  * @suspend: Executed before putting the system into a sleep state in which the
  *	contents of main memory are preserved.  The exact action to perform
@@ -546,6 +565,7 @@ struct dev_pm_info {
 	bool			is_late_suspended:1;
 	bool			ignore_children:1;
 	bool			early_init:1;	/* Owned by the PM core */
+	bool			direct_complete:1;	/* Owned by the PM core */
 	spinlock_t		lock;
 #ifdef CONFIG_PM_SLEEP
 	struct list_head	entry;

include/linux/pm_runtime.h

@@ -101,6 +101,11 @@ static inline bool pm_runtime_status_suspended(struct device *dev)
 	return dev->power.runtime_status == RPM_SUSPENDED;
 }
 
+static inline bool pm_runtime_suspended_if_enabled(struct device *dev)
+{
+	return pm_runtime_status_suspended(dev) && dev->power.disable_depth == 1;
+}
+
 static inline bool pm_runtime_enabled(struct device *dev)
 {
 	return !dev->power.disable_depth;
@@ -150,6 +155,7 @@ static inline void device_set_run_wake(struct device *dev, bool enable) {}
 static inline bool pm_runtime_suspended(struct device *dev) { return false; }
 static inline bool pm_runtime_active(struct device *dev) { return true; }
 static inline bool pm_runtime_status_suspended(struct device *dev) { return false; }
+static inline bool pm_runtime_suspended_if_enabled(struct device *dev) { return false; }
 static inline bool pm_runtime_enabled(struct device *dev) { return false; }
 
 static inline void pm_runtime_no_callbacks(struct device *dev) {}

kernel/power/hibernate.c

@@ -35,7 +35,7 @@
 static int nocompress;
 static int noresume;
 static int resume_wait;
-static int resume_delay;
+static unsigned int resume_delay;
 static char resume_file[256] = CONFIG_PM_STD_PARTITION;
 dev_t swsusp_resume_device;
 sector_t swsusp_resume_block;
@@ -228,19 +228,23 @@ static void platform_recover(int platform_mode)
 void swsusp_show_speed(struct timeval *start, struct timeval *stop,
 			unsigned nr_pages, char *msg)
 {
-	s64 elapsed_centisecs64;
-	int centisecs;
-	int k;
-	int kps;
+	u64 elapsed_centisecs64;
+	unsigned int centisecs;
+	unsigned int k;
+	unsigned int kps;
 
 	elapsed_centisecs64 = timeval_to_ns(stop) - timeval_to_ns(start);
+	/*
+	 * If "(s64)elapsed_centisecs64 < 0", it will print long elapsed time,
+	 * it is obvious enough for what went wrong.
+	 */
 	do_div(elapsed_centisecs64, NSEC_PER_SEC / 100);
 	centisecs = elapsed_centisecs64;
 	if (centisecs == 0)
 		centisecs = 1;	/* avoid div-by-zero */
 	k = nr_pages * (PAGE_SIZE / 1024);
 	kps = (k * 100) / centisecs;
-	printk(KERN_INFO "PM: %s %d kbytes in %d.%02d seconds (%d.%02d MB/s)\n",
+	printk(KERN_INFO "PM: %s %u kbytes in %u.%02u seconds (%u.%02u MB/s)\n",
 			msg, k,
 			centisecs / 100, centisecs % 100,
 			kps / 1000, (kps % 1000) / 10);
@@ -595,7 +599,8 @@ static void power_down(void)
 	case HIBERNATION_PLATFORM:
 		hibernation_platform_enter();
 	case HIBERNATION_SHUTDOWN:
-		kernel_power_off();
+		if (pm_power_off)
+			kernel_power_off();
 		break;
 #ifdef CONFIG_SUSPEND
 	case HIBERNATION_SUSPEND:
@@ -623,7 +628,8 @@ static void power_down(void)
 	 * corruption after resume.
 	 */
 	printk(KERN_CRIT "PM: Please power down manually\n");
-	while(1);
+	while (1)
+		cpu_relax();
 }
 
 /**
@@ -1109,7 +1115,10 @@ static int __init resumewait_setup(char *str)
 
 static int __init resumedelay_setup(char *str)
 {
-	resume_delay = simple_strtoul(str, NULL, 0);
+	int rc = kstrtouint(str, 0, &resume_delay);
+
+	if (rc)
+		return rc;
 	return 1;
 }
 

kernel/power/main.c

@@ -279,26 +279,26 @@ static inline void pm_print_times_init(void) {}
 struct kobject *power_kobj;
 
 /**
- *	state - control system power state.
+ * state - control system sleep states.
  *
- *	show() returns what states are supported, which is hard-coded to
- *	'freeze' (Low-Power Idle), 'standby' (Power-On Suspend),
- *	'mem' (Suspend-to-RAM), and 'disk' (Suspend-to-Disk).
+ * show() returns available sleep state labels, which may be "mem", "standby",
+ * "freeze" and "disk" (hibernation).  See Documentation/power/states.txt for a
+ * description of what they mean.
  *
- *	store() accepts one of those strings, translates it into the
- *	proper enumerated value, and initiates a suspend transition.
+ * store() accepts one of those strings, translates it into the proper
+ * enumerated value, and initiates a suspend transition.
  */
 static ssize_t state_show(struct kobject *kobj, struct kobj_attribute *attr,
 			  char *buf)
 {
 	char *s = buf;
 #ifdef CONFIG_SUSPEND
-	int i;
+	suspend_state_t i;
+
+	for (i = PM_SUSPEND_MIN; i < PM_SUSPEND_MAX; i++)
+		if (pm_states[i].state)
+			s += sprintf(s,"%s ", pm_states[i].label);
 
-	for (i = 0; i < PM_SUSPEND_MAX; i++) {
-		if (pm_states[i] && valid_state(i))
-			s += sprintf(s,"%s ", pm_states[i]);
-	}
 #endif
 #ifdef CONFIG_HIBERNATION
 	s += sprintf(s, "%s\n", "disk");
@@ -314,7 +314,7 @@ static suspend_state_t decode_state(const char *buf, size_t n)
 {
 #ifdef CONFIG_SUSPEND
 	suspend_state_t state = PM_SUSPEND_MIN;
-	const char * const *s;
+	struct pm_sleep_state *s;
 #endif
 	char *p;
 	int len;
@@ -328,8 +328,9 @@ static suspend_state_t decode_state(const char *buf, size_t n)
 
 #ifdef CONFIG_SUSPEND
 	for (s = &pm_states[state]; state < PM_SUSPEND_MAX; s++, state++)
-		if (*s && len == strlen(*s) && !strncmp(buf, *s, len))
-			return state;
+		if (s->state && len == strlen(s->label)
+		    && !strncmp(buf, s->label, len))
+			return s->state;
 #endif
 
 	return PM_SUSPEND_ON;
@@ -447,8 +448,8 @@ static ssize_t autosleep_show(struct kobject *kobj,
 
 #ifdef CONFIG_SUSPEND
 	if (state < PM_SUSPEND_MAX)
-		return sprintf(buf, "%s\n", valid_state(state) ?
-						pm_states[state] : "error");
+		return sprintf(buf, "%s\n", pm_states[state].state ?
+					pm_states[state].label : "error");
 #endif
 #ifdef CONFIG_HIBERNATION
 	return sprintf(buf, "disk\n");

kernel/power/power.h

@@ -178,17 +178,20 @@ extern void swsusp_show_speed(struct timeval *, struct timeval *,
 				unsigned int, char *);
 
 #ifdef CONFIG_SUSPEND
+struct pm_sleep_state {
+	const char *label;
+	suspend_state_t state;
+};
+
 /* kernel/power/suspend.c */
-extern const char *const pm_states[];
+extern struct pm_sleep_state pm_states[];
 
-extern bool valid_state(suspend_state_t state);
 extern int suspend_devices_and_enter(suspend_state_t state);
 #else /* !CONFIG_SUSPEND */
 static inline int suspend_devices_and_enter(suspend_state_t state)
 {
 	return -ENOSYS;
 }
-static inline bool valid_state(suspend_state_t state) { return false; }
 #endif /* !CONFIG_SUSPEND */
 
 #ifdef CONFIG_PM_TEST_SUSPEND

kernel/power/suspend.c

@@ -31,10 +31,10 @@
 
 #include "power.h"
 
-const char *const pm_states[PM_SUSPEND_MAX] = {
-	[PM_SUSPEND_FREEZE]	= "freeze",
-	[PM_SUSPEND_STANDBY]	= "standby",
-	[PM_SUSPEND_MEM]	= "mem",
+struct pm_sleep_state pm_states[PM_SUSPEND_MAX] = {
+	[PM_SUSPEND_FREEZE] = { .label = "freeze", .state = PM_SUSPEND_FREEZE },
+	[PM_SUSPEND_STANDBY] = { .label = "standby", },
+	[PM_SUSPEND_MEM] = { .label = "mem", },
 };
 
 static const struct platform_suspend_ops *suspend_ops;
@@ -54,9 +54,11 @@ static void freeze_begin(void)
 
 static void freeze_enter(void)
 {
+	cpuidle_use_deepest_state(true);
 	cpuidle_resume();
 	wait_event(suspend_freeze_wait_head, suspend_freeze_wake);
 	cpuidle_pause();
+	cpuidle_use_deepest_state(false);
 }
 
 void freeze_wake(void)
@@ -66,42 +68,62 @@ void freeze_wake(void)
 }
 EXPORT_SYMBOL_GPL(freeze_wake);
 
+static bool valid_state(suspend_state_t state)
+{
+	/*
+	 * PM_SUSPEND_STANDBY and PM_SUSPEND_MEM states need low level
+	 * support and need to be valid to the low level
+	 * implementation, no valid callback implies that none are valid.
+	 */
+	return suspend_ops && suspend_ops->valid && suspend_ops->valid(state);
+}
+
+/*
+ * If this is set, the "mem" label always corresponds to the deepest sleep state
+ * available, the "standby" label corresponds to the second deepest sleep state
+ * available (if any), and the "freeze" label corresponds to the remaining
+ * available sleep state (if there is one).
+ */
+static bool relative_states;
+
+static int __init sleep_states_setup(char *str)
+{
+	relative_states = !strncmp(str, "1", 1);
+	if (relative_states) {
+		pm_states[PM_SUSPEND_MEM].state = PM_SUSPEND_FREEZE;
+		pm_states[PM_SUSPEND_FREEZE].state = 0;
+	}
+	return 1;
+}
+
+__setup("relative_sleep_states=", sleep_states_setup);
+
 /**
  * suspend_set_ops - Set the global suspend method table.
  * @ops: Suspend operations to use.
  */
 void suspend_set_ops(const struct platform_suspend_ops *ops)
 {
+	suspend_state_t i;
+	int j = PM_SUSPEND_MAX - 1;
+
 	lock_system_sleep();
+
 	suspend_ops = ops;
+	for (i = PM_SUSPEND_MEM; i >= PM_SUSPEND_STANDBY; i--)
+		if (valid_state(i))
+			pm_states[j--].state = i;
+		else if (!relative_states)
+			pm_states[j--].state = 0;
+
+	pm_states[j--].state = PM_SUSPEND_FREEZE;
+	while (j >= PM_SUSPEND_MIN)
+		pm_states[j--].state = 0;
+
 	unlock_system_sleep();
 }
 EXPORT_SYMBOL_GPL(suspend_set_ops);
 
-bool valid_state(suspend_state_t state)
-{
-	if (state == PM_SUSPEND_FREEZE) {
-#ifdef CONFIG_PM_DEBUG
-		if (pm_test_level != TEST_NONE &&
-		    pm_test_level != TEST_FREEZER &&
-		    pm_test_level != TEST_DEVICES &&
-		    pm_test_level != TEST_PLATFORM) {
-			printk(KERN_WARNING "Unsupported pm_test mode for "
-					"freeze state, please choose "
-					"none/freezer/devices/platform.\n");
-			return false;
-		}
-#endif
-			return true;
-	}
-	/*
-	 * PM_SUSPEND_STANDBY and PM_SUSPEND_MEMORY states need lowlevel
-	 * support and need to be valid to the lowlevel
-	 * implementation, no valid callback implies that none are valid.
-	 */
-	return suspend_ops && suspend_ops->valid && suspend_ops->valid(state);
-}
-
 /**
  * suspend_valid_only_mem - Generic memory-only valid callback.
  *
@@ -328,9 +350,17 @@ static int enter_state(suspend_state_t state)
 {
 	int error;
 
-	if (!valid_state(state))
-		return -ENODEV;
-
+	if (state == PM_SUSPEND_FREEZE) {
+#ifdef CONFIG_PM_DEBUG
+		if (pm_test_level != TEST_NONE && pm_test_level <= TEST_CPUS) {
+			pr_warning("PM: Unsupported test mode for freeze state,"
+				   "please choose none/freezer/devices/platform.\n");
+			return -EAGAIN;
+		}
+#endif
+	} else if (!valid_state(state)) {
+		return -EINVAL;
+	}
 	if (!mutex_trylock(&pm_mutex))
 		return -EBUSY;
 
@@ -341,7 +371,7 @@ static int enter_state(suspend_state_t state)
 	sys_sync();
 	printk("done.\n");
 
-	pr_debug("PM: Preparing system for %s sleep\n", pm_states[state]);
+	pr_debug("PM: Preparing system for %s sleep\n", pm_states[state].label);
 	error = suspend_prepare(state);
 	if (error)
 		goto Unlock;
@@ -349,7 +379,7 @@ static int enter_state(suspend_state_t state)
 	if (suspend_test(TEST_FREEZER))
 		goto Finish;
 
-	pr_debug("PM: Entering %s sleep\n", pm_states[state]);
+	pr_debug("PM: Entering %s sleep\n", pm_states[state].label);
 	pm_restrict_gfp_mask();
 	error = suspend_devices_and_enter(state);
 	pm_restore_gfp_mask();

kernel/power/suspend_test.c

@@ -92,13 +92,13 @@ static void __init test_wakealarm(struct rtc_device *rtc, suspend_state_t state)
 	}
 
 	if (state == PM_SUSPEND_MEM) {
-		printk(info_test, pm_states[state]);
+		printk(info_test, pm_states[state].label);
 		status = pm_suspend(state);
 		if (status == -ENODEV)
 			state = PM_SUSPEND_STANDBY;
 	}
 	if (state == PM_SUSPEND_STANDBY) {
-		printk(info_test, pm_states[state]);
+		printk(info_test, pm_states[state].label);
 		status = pm_suspend(state);
 	}
 	if (status < 0)
@@ -136,18 +136,16 @@ static char warn_bad_state[] __initdata =
 
 static int __init setup_test_suspend(char *value)
 {
-	unsigned i;
+	suspend_state_t i;
 
 	/* "=mem" ==> "mem" */
 	value++;
-	for (i = 0; i < PM_SUSPEND_MAX; i++) {
-		if (!pm_states[i])
-			continue;
-		if (strcmp(pm_states[i], value) != 0)
-			continue;
-		test_state = (__force suspend_state_t) i;
-		return 0;
-	}
+	for (i = PM_SUSPEND_MIN; i < PM_SUSPEND_MAX; i++)
+		if (!strcmp(pm_states[i].label, value)) {
+			test_state = pm_states[i].state;
+			return 0;
+		}
+
 	printk(warn_bad_state, value);
 	return 0;
 }
@@ -164,8 +162,8 @@ static int __init test_suspend(void)
 	/* PM is initialized by now; is that state testable? */
 	if (test_state == PM_SUSPEND_ON)
 		goto done;
-	if (!valid_state(test_state)) {
-		printk(warn_bad_state, pm_states[test_state]);
+	if (!pm_states[test_state].state) {
+		printk(warn_bad_state, pm_states[test_state].label);
 		goto done;
 	}
 

kernel/sched/idle.c

@@ -101,19 +101,13 @@ static int cpuidle_idle_call(void)
 	rcu_idle_enter();
 
 	/*
-	 * Check if the cpuidle framework is ready, otherwise fallback
-	 * to the default arch specific idle method
+	 * Ask the cpuidle framework to choose a convenient idle state.
+	 * Fall back to the default arch specific idle method on errors.
 	 */
-	ret = cpuidle_enabled(drv, dev);
-
-	if (!ret) {
-		/*
-		 * Ask the governor to choose an idle state it thinks
-		 * it is convenient to go to. There is *always* a
-		 * convenient idle state
-		 */
-		next_state = cpuidle_select(drv, dev);
+	next_state = cpuidle_select(drv, dev);
 
+	ret = next_state;
+	if (ret >= 0) {
 		/*
 		 * The idle task must be scheduled, it is pointless to
 		 * go to idle, just update no idle residency and get
@@ -140,7 +134,7 @@ static int cpuidle_idle_call(void)
 					CLOCK_EVT_NOTIFY_BROADCAST_ENTER,
 					&dev->cpu);
 
-			if (!ret) {
+			if (ret >= 0) {
 				trace_cpu_idle_rcuidle(next_state, dev->cpu);
 
 				/*
@@ -175,7 +169,7 @@ static int cpuidle_idle_call(void)
 	 * We can't use the cpuidle framework, let's use the default
 	 * idle routine
 	 */
-	if (ret)
+	if (ret < 0)
 		arch_cpu_idle();
 
 	__current_set_polling();