[RFC][PATCH 1/3] PM: Introduce new top level suspend and hibernation callbacks (rev. 5)

[RFC][PATCH 1/3] PM: Introduce new top level suspend and hibernation callbacks (rev. 5)

[Rafael J. Wysocki]

From: Rafael J. Wysocki <rjw@sisk.pl>

Introduce 'struct pm_ops' and 'struct pm_ext_ops' representing
suspend and hibernation operations for bus types, device classes and
device types.

Modify the PM core to use 'struct pm_ops' and 'struct pm_ext_ops'
objects, if defined, instead of the ->suspend() and ->resume() or,
respectively, ->suspend_late() and ->resume_early() callbacks that
will be considered as legacy and gradually phased out.

The main purpose of doing this is to separate suspend (aka S2RAM and
standby) callbacks from hibernation callbacks in such a way that the
new callbacks won't take arguments and the semantics of each of them
will be clearly specified.  This has been requested for multiple
times by many people, including Linus himself, and the reason is that
within the current scheme if ->resume() is called, for example, it's
difficult to say why it's been called (ie. is it a resume from RAM or
from hibernation or a suspend/hibernation failure etc.?).

The second purpose is to make the suspend/hibernation callbacks more
flexible so that device drivers can handle more than they can within
the current scheme.  For example, some drivers may need to prevent
new children of the device from being registered before their
->suspend() callbacks are executed or they may want to carry out some
operations requiring the availability of some other devices, not
directly bound via the parent-child relationship, in order to prepare
for the execution of ->suspend(), etc.

Ultimately, we'd like to stop using the freezing of tasks for suspend
and therefore the drivers' suspend/hibernation code will have to take
care of the handling of the user space during suspend/hibernation.
That, in turn, would be difficult within the current scheme, without
the new ->prepare() and ->complete() callbacks.

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

 arch/x86/kernel/apm_32.c   |    4 
 drivers/base/power/main.c  |  693 ++++++++++++++++++++++++++++++++++-----------
 drivers/base/power/power.h |    2 
 drivers/base/power/trace.c |    4 
 include/linux/device.h     |    9 
 include/linux/pm.h         |  318 ++++++++++++++++++--
 kernel/power/disk.c        |   20 -
 kernel/power/main.c        |    6 
 8 files changed, 857 insertions(+), 199 deletions(-)

Index: linux-2.6/include/linux/pm.h
===================================================================
--- linux-2.6.orig/include/linux/pm.h
+++ linux-2.6/include/linux/pm.h
@@ -114,7 +114,9 @@ typedef struct pm_message {
 	int event;
 } pm_message_t;
 
-/*
+/**
+ * struct pm_ops - device PM callbacks
+ *
  * Several driver power state transitions are externally visible, affecting
  * the state of pending I/O queues and (for drivers that touch hardware)
  * interrupts, wakeups, DMA, and other hardware state.  There may also be
@@ -122,6 +124,288 @@ typedef struct pm_message {
  * to the rest of the driver stack (such as a driver that's ON gating off
  * clocks which are not in active use).
  *
+ * The externally visible transitions are handled with the help of the following
+ * callbacks included in this structure:
+ *
+ * @prepare: Prepare the device for the upcoming transition, but do NOT change
+ *	its hardware state.  Prevent new children of the device from being
+ *	registered after @prepare() returns (the driver's subsystem and
+ *	generally the rest of the kernel is supposed to prevent new calls to the
+ *	probe method from being made too once @prepare() has succeeded).  If
+ *	@prepare() detects a situation it cannot handle (e.g. registration of a
+ *	child already in progress), it may return -EAGAIN, so that the PM core
+ *	can execute it once again (e.g. after the new child has 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 @prepare() for all devices before starting to
+ *	execute suspend callbacks for any of them, so drivers may assume all of
+ *	the other devices to be present and functional while @prepare() is being
+ *	executed.  In particular, it is safe to make GFP_KERNEL memory
+ *	allocations from within @prepare(), although they are likely to fail in
+ *	case of hibernation, if a substantial amount of memory is requested.
+ *	However, drivers may NOT assume anything about the availability of the
+ *	user space at that time and it is not correct to request firmware from
+ *	within @prepare() (it's too late to do that).
+ *
+ * @complete: Undo the changes made by @prepare().  This method is executed for
+ *	all kinds of resume transitions, following one of the resume callbacks:
+ *	@resume(), @thaw(), @restore().  Also called if the state transition
+ *	fails before the driver's suspend callback (@suspend(), @freeze(),
+ *	@poweroff()) can be executed (e.g. if the suspend callback fails for one
+ *	of the other devices that the PM core has unsucessfully attempted to
+ *	suspend earlier).
+ *	The PM core executes @complete() after it has executed the appropriate
+ *	resume callback for all devices.
+ *
+ * @suspend: Executed before putting the system into a sleep state in which the
+ *	contents of main memory are preserved.  Quiesce the device, put it into
+ *	a low power state appropriate for the upcoming system state (such as
+ *	PCI_D3hot), and enable wakeup events as appropriate.
+ *
+ * @resume: Executed after waking the system up from a sleep state in which the
+ *	contents of main memory were preserved.  Put the device into the
+ *	appropriate state, according to the information saved in memory by the
+ *	preceding @suspend().  The driver starts working again, responding to
+ *	hardware events and software requests.  The hardware may have gone
+ *	through a power-off reset, or it may have maintained state from the
+ *	previous suspend() which the driver may rely on while resuming.  On most
+ *	platforms, there are no restrictions on availability of resources like
+ *	clocks during @resume().
+ *
+ * @freeze: Hibernation-specific, executed before creating a hibernation image.
+ *	Quiesce operations so that a consistent image can be created, but do NOT
+ *	otherwise put the device into a low power device state and do NOT emit
+ *	system wakeup events.  Save in main memory the device settings to be
+ *	used by @restore() during the subsequent resume from hibernation or by
+ *	the subsequent @thaw(), if the creation of the image or the restoration
+ *	of main memory contents from it fails.
+ *
+ * @thaw: Hibernation-specific, executed after creating a hibernation image OR
+ *	if the creation of the image fails.  Also executed after a failing
+ *	attempt to restore the contents of main memory from such an image.
+ *	Undo the changes made by the preceding @freeze(), so the device can be
+ *	operated in the same way as immediately before the call to @freeze().
+ *
+ * @poweroff: Hibernation-specific, executed after saving a hibernation image.
+ *	Quiesce the device, put it into a low power state appropriate for the
+ *	upcoming system state (such as PCI_D3hot), and enable wakeup events as
+ *	appropriate.
+ *
+ * @restore: Hibernation-specific, executed after restoring the contents of main
+ *	memory from a hibernation image.  Driver starts working again,
+ *	responding to hardware events and software requests.  Drivers may NOT
+ *	make ANY assumptions about the hardware state right prior to @restore().
+ *	On most platforms, there are no restrictions on availability of
+ *	resources like clocks during @restore().
+ *
+ * All of the above callbacks, except for @complete(), return error codes.
+ * However, the error codes returned by the resume operations, @resume(),
+ * @thaw(), and @restore(), do not cause the PM core to abort the resume
+ * transition during which they are returned.  Instead, the PM core marks
+ * the devices for which they are returned and all of their children as
+ * "invalid" and doesn't attempt to execute any other suspend/hibernation
+ * callbacks for them (including @complete()).  If a device marked as "invalid"
+ * is encountered during the preparation phase (i.e. when devices' @prepare()
+ * methods are executed), the transition will be aborted and -EINVAL will be
+ * returned. [The only way to recover from this situation is to unregister the
+ * "invalid" device(s).]
+ *
+ * It is allowed to unregister devices while the above callbacks are being
+ * executed.  However, it is not allowed to unregister a device from within any
+ * of its own callbacks.
+ */
+
+struct pm_ops {
+	int (*prepare)(struct device *dev);
+	void (*complete)(struct device *dev);
+	int (*suspend)(struct device *dev);
+	int (*resume)(struct device *dev);
+	int (*freeze)(struct device *dev);
+	int (*thaw)(struct device *dev);
+	int (*poweroff)(struct device *dev);
+	int (*restore)(struct device *dev);
+};
+
+/**
+ * struct pm_ext_ops - extended device PM callbacks
+ *
+ * Some devices require certain operations related to suspend and hibernation
+ * to be carried out with interrupts disabled.  Thus, 'struct pm_ext_ops' below
+ * is defined, adding callbacks to be executed with interrupts disabled to
+ * 'struct pm_ops'.
+ *
+ * The following callbacks included in 'struct pm_ext_ops' are executed with
+ * the nonboot CPUs switched off and with interrupts disabled on the only
+ * functional CPU.  They also are executed with the PM core list of devices
+ * locked, so they must NOT unregister any devices.
+ *
+ * @suspend_noirq: Complete the operations of ->suspend() by carrying out any
+ *	actions required for suspending the device that need interrupts to be
+ *	disabled
+ *
+ * @resume_noirq: Prepare for the execution of ->resume() by carrying out any
+ *	actions required for resuming the device that need interrupts to be
+ *	disabled
+ *
+ * @freeze_noirq: Complete the operations of ->freeze() by carrying out any
+ *	actions required for freezing the device that need interrupts to be
+ *	disabled
+ *
+ * @thaw_noirq: Prepare for the execution of ->thaw() by carrying out any
+ *	actions required for thawing the device that need interrupts to be
+ *	disabled
+ *
+ * @poweroff_noirq: Complete the operations of ->poweroff() by carrying out any
+ *	actions required for handling the device that need interrupts to be
+ *	disabled
+ *
+ * @restore_noirq: Prepare for the execution of ->restore() by carrying out any
+ *	actions required for restoring the operations of the device that need
+ *	interrupts to be disabled
+ *
+ * All of the above callbacks return error codes, but the error codes returned
+ * by the resume operations, @resume_noirq(), @thaw_noirq(), and
+ * @restore_noirq(), do not cause the PM core to abort the resume transition
+ * during which they are returned.  Instead, the PM core marks the devices for
+ * which they are returned and all of their children as "invalid" and doesn't
+ * attempt to execute any resume callbacks for them (including ->complete()).
+ */
+
+struct pm_ext_ops {
+	struct pm_ops base;
+	int (*suspend_noirq)(struct device *dev);
+	int (*resume_noirq)(struct device *dev);
+	int (*freeze_noirq)(struct device *dev);
+	int (*thaw_noirq)(struct device *dev);
+	int (*poweroff_noirq)(struct device *dev);
+	int (*restore_noirq)(struct device *dev);
+};
+
+/**
+ * PM_EVENT_ messages
+ *
+ * The following PM_EVENT_ messages are defined for the internal use of the PM
+ * core, in order to provide a mechanism allowing the high level suspend and
+ * hibernation code to convey the necessary information to the device PM core
+ * code:
+ *
+ * ON		No transition.
+ *
+ * FREEZE 	System is going to hibernate, call ->prepare() and ->freeze()
+ *		for all devices.
+ *
+ * SUSPEND	System is going to suspend, call ->prepare() and ->suspend()
+ *		for all devices.
+ *
+ * HIBERNATE	Hibernation image has been saved, call ->prepare() and
+ *		->poweroff() for all devices.
+ *
+ * QUIESCE	Contents of main memory are going to be restored from a (loaded)
+ *		hibernation image, call ->prepare() and ->freeze() for all
+ *		devices.
+ *
+ * RESUME	System is resuming, call ->resume() and ->complete() for all
+ *		devices.
+ *
+ * THAW		Hibernation image has been created, call ->thaw() and
+ *		->complete() for all devices.
+ *
+ * RESTORE	Contents of main memory have been restored from a hibernation
+ *		image, call ->restore() and ->complete() for all devices.
+ *
+ * RECOVER	Creation of a hibernation image or restoration of the main
+ *		memory contents from a hibernation image has failed, call
+ *		->thaw() and ->complete() for all devices.
+ */
+
+#define PM_EVENT_ON		0x0000
+#define PM_EVENT_FREEZE 	0x0001
+#define PM_EVENT_SUSPEND	0x0002
+#define PM_EVENT_HIBERNATE	0x0004
+#define PM_EVENT_QUIESCE	0x0008
+#define PM_EVENT_RESUME		0x0010
+#define PM_EVENT_THAW		0x0020
+#define PM_EVENT_RESTORE	0x0040
+#define PM_EVENT_RECOVER	0x0080
+
+#define PM_EVENT_SLEEP	(PM_EVENT_SUSPEND | PM_EVENT_HIBERNATE)
+
+#define PMSG_FREEZE	((struct pm_message){ .event = PM_EVENT_FREEZE, })
+#define PMSG_QUIESCE	((struct pm_message){ .event = PM_EVENT_QUIESCE, })
+#define PMSG_SUSPEND	((struct pm_message){ .event = PM_EVENT_SUSPEND, })
+#define PMSG_HIBERNATE	((struct pm_message){ .event = PM_EVENT_HIBERNATE, })
+#define PMSG_RESUME	((struct pm_message){ .event = PM_EVENT_RESUME, })
+#define PMSG_THAW	((struct pm_message){ .event = PM_EVENT_THAW, })
+#define PMSG_RESTORE	((struct pm_message){ .event = PM_EVENT_RESTORE, })
+#define PMSG_RECOVER	((struct pm_message){ .event = PM_EVENT_RECOVER, })
+#define PMSG_ON		((struct pm_message){ .event = PM_EVENT_ON, })
+
+/**
+ * Device power management states
+ *
+ * These state labels are used internally by the PM core to indicate the current
+ * status of a device with respect to the PM core operations.
+ *
+ * DPM_INVALID		Device is not in a consistent state.  Set when one of
+ *			the device's resume callbacks, ->resume(), ->thaw(),
+ *			->restore(), ->resume()_noirq, ->thaw_noirq(), or
+ *			->restore_noirq(), fails.  Also set when the device
+ *			parent's status turns out to be DPM_INVALID.
+ *
+ * DPM_ON		Device is regarded as operational.  Set this way
+ *			initially and when ->complete() is about to be called.
+ *			Also set when ->prepare() fails.
+ *
+ * DPM_PREPARING	Device is going to be prepared for a PM transition.  Set
+ *			when ->prepare() is about to be called.
+ *
+ * DPM_RESUMING		Device is going to be resumed.  Set when ->resume(),
+ *			->thaw(), or ->restore() is about to be called.
+ *
+ * DPM_SUSPENDING	Device has been prepared for a power transition.  Set
+ *			when ->prepare() has just succeeded.
+ *
+ * DPM_OFF		Device is regarded as inactive.  Set immediately after
+ *			->suspend(), ->freeze(), or ->poweroff() has succeeded.
+ *			Also set when ->resume()_noirq, ->thaw_noirq(), or
+ *			->restore_noirq() is about to be called.
+ *
+ * DPM_OFF_IRQ		Device is in a "deep sleep".  Set immediately after
+ *			->suspend_noirq(), ->freeze_noirq(), or
+ *			->poweroff_noirq() has just succeeded.
+ */
+
+enum dpm_state {
+	DPM_INVALID,
+	DPM_ON,
+	DPM_PREPARING,
+	DPM_RESUMING,
+	DPM_SUSPENDING,
+	DPM_OFF,
+	DPM_OFF_IRQ,
+};
+
+struct dev_pm_info {
+	pm_message_t		power_state;
+	unsigned		can_wakeup:1;
+	unsigned		should_wakeup:1;
+	enum dpm_state		status;		/* Owned by the PM core */
+#ifdef	CONFIG_PM_SLEEP
+	struct list_head	entry;
+#endif
+};
+
+/*
+ * The PM_EVENT_ messages are also used by drivers implementing the legacy
+ * suspend framework, based on the ->suspend() and ->resume() callbacks common
+ * for suspend and hibernation transitions, according to the rules below.
+ */
+
+/* Necessary, because several drivers use PM_EVENT_PRETHAW */
+#define PM_EVENT_PRETHAW PM_EVENT_QUIESCE
+
+/*
  * One transition is triggered by resume(), after a suspend() call; the
  * message is implicit:
  *
@@ -166,35 +450,13 @@ typedef struct pm_message {
  * or from system low-power states such as standby or suspend-to-RAM.
  */
 
-#define PM_EVENT_ON 0
-#define PM_EVENT_FREEZE 1
-#define PM_EVENT_SUSPEND 2
-#define PM_EVENT_HIBERNATE 4
-#define PM_EVENT_PRETHAW 8
-
-#define PM_EVENT_SLEEP	(PM_EVENT_SUSPEND | PM_EVENT_HIBERNATE)
-
-#define PMSG_FREEZE	((struct pm_message){ .event = PM_EVENT_FREEZE, })
-#define PMSG_PRETHAW	((struct pm_message){ .event = PM_EVENT_PRETHAW, })
-#define PMSG_SUSPEND	((struct pm_message){ .event = PM_EVENT_SUSPEND, })
-#define PMSG_HIBERNATE	((struct pm_message){ .event = PM_EVENT_HIBERNATE, })
-#define PMSG_ON		((struct pm_message){ .event = PM_EVENT_ON, })
-
-struct dev_pm_info {
-	pm_message_t		power_state;
-	unsigned		can_wakeup:1;
-	unsigned		should_wakeup:1;
-	bool			sleeping:1;	/* Owned by the PM core */
-#ifdef	CONFIG_PM_SLEEP
-	struct list_head	entry;
-#endif
-};
+#ifdef CONFIG_PM_SLEEP
+extern void device_pm_lock(void);
+extern void device_power_up(pm_message_t state);
+extern void device_resume(pm_message_t state);
 
+extern void device_pm_unlock(void);
 extern int device_power_down(pm_message_t state);
-extern void device_power_up(void);
-extern void device_resume(void);
-
-#ifdef CONFIG_PM_SLEEP
 extern int device_suspend(pm_message_t state);
 extern int device_prepare_suspend(pm_message_t state);
 
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
@@ -12,11 +12,9 @@
  * and add it to the list of power-controlled devices. sysfs entries for
  * controlling device power management will also be added.
  *
- * A different set of lists than the global subsystem list are used to
- * keep track of power info because we use different lists to hold
- * devices based on what stage of the power management process they
- * are in. The power domain dependencies may also differ from the
- * ancestral dependencies that the subsystem list maintains.
+ * A separate list is used for keeping track of power info, because the power
+ * domain dependencies may differ from the ancestral dependencies that the
+ * subsystem list maintains.
  */
 
 #include <linux/device.h>
@@ -30,31 +28,40 @@
 #include "power.h"
 
 /*
- * The entries in the dpm_active list are in a depth first order, simply
+ * The entries in the dpm_list list are in a depth first order, simply
  * because children are guaranteed to be discovered after parents, and
  * are inserted at the back of the list on discovery.
  *
- * All the other lists are kept in the same order, for consistency.
- * However the lists aren't always traversed in the same order.
- * Semaphores must be acquired from the top (i.e., front) down
- * and released in the opposite order.  Devices must be suspended
- * from the bottom (i.e., end) up and resumed in the opposite order.
- * That way no parent will be suspended while it still has an active
- * child.
- *
  * Since device_pm_add() may be called with a device semaphore held,
  * we must never try to acquire a device semaphore while holding
  * dpm_list_mutex.
  */
 
-LIST_HEAD(dpm_active);
-static LIST_HEAD(dpm_off);
-static LIST_HEAD(dpm_off_irq);
+LIST_HEAD(dpm_list);
 
 static DEFINE_MUTEX(dpm_list_mtx);
 
-/* 'true' if all devices have been suspended, protected by dpm_list_mtx */
-static bool all_sleeping;
+/*
+ * Set once the preparation of devices for a PM transition has started, reset
+ * before starting to resume devices.  Protected by dpm_list_mtx.
+ */
+static bool transition_started;
+
+/**
+ *	device_pm_lock - lock the list of active devices used by the PM core
+ */
+void device_pm_lock(void)
+{
+	mutex_lock(&dpm_list_mtx);
+}
+
+/**
+ *	device_pm_unlock - unlock the list of active devices used by the PM core
+ */
+void device_pm_unlock(void)
+{
+	mutex_unlock(&dpm_list_mtx);
+}
 
 /**
  *	device_pm_add - add a device to the list of active devices
@@ -68,22 +75,36 @@ int device_pm_add(struct device *dev)
 		 dev->bus ? dev->bus->name : "No Bus",
 		 kobject_name(&dev->kobj));
 	mutex_lock(&dpm_list_mtx);
-	if ((dev->parent && dev->parent->power.sleeping) || all_sleeping) {
-		if (dev->parent->power.sleeping)
-			dev_warn(dev,
-				"parent %s is sleeping, will not add\n",
+	if (dev->parent) {
+		if (dev->parent->power.status == DPM_INVALID) {
+			dev_warn(dev, "state of the parent %s is inconsistent, "
+				"will not add\n", dev->parent->bus_id);
+			goto Refuse;
+		} else if (dev->parent->power.status >= DPM_SUSPENDING) {
+			dev_warn(dev, "parent %s is sleeping, will not add\n",
 				dev->parent->bus_id);
-		else
-			dev_warn(dev, "devices are sleeping, will not add\n");
-		WARN_ON(true);
-		error = -EBUSY;
-	} else {
-		error = dpm_sysfs_add(dev);
-		if (!error)
-			list_add_tail(&dev->power.entry, &dpm_active);
+			goto Refuse;
+		}
+	} else if (transition_started) {
+		/*
+		 * We refuse to register parentless devices while a PM
+		 * transition is in progress in order to avoid leaving them
+		 * unhandled down the road
+		 */
+		goto Refuse;
+	}
+	error = dpm_sysfs_add(dev);
+	if (!error) {
+		dev->power.status = DPM_ON;
+		list_add_tail(&dev->power.entry, &dpm_list);
 	}
+ End:
 	mutex_unlock(&dpm_list_mtx);
 	return error;
+ Refuse:
+	WARN_ON(true);
+	error = -EBUSY;
+	goto End;
 }
 
 /**
@@ -99,77 +120,242 @@ void device_pm_remove(struct device *dev
 		 kobject_name(&dev->kobj));
 	mutex_lock(&dpm_list_mtx);
 	dpm_sysfs_remove(dev);
+	dev->power.status = DPM_INVALID;
 	list_del_init(&dev->power.entry);
 	mutex_unlock(&dpm_list_mtx);
 }
 
+/**
+ *	pm_op - execute the PM operation appropiate for given PM event
+ *	@dev:	Device.
+ *	@ops:	PM operations to choose from.
+ *	@state:	PM transition of the system being carried out.
+ */
+static int pm_op(struct device *dev, struct pm_ops *ops, pm_message_t state)
+{
+	int error = 0;
+
+	switch (state.event) {
+#ifdef CONFIG_SUSPEND
+	case PM_EVENT_SUSPEND:
+		if (ops->suspend) {
+			error = ops->suspend(dev);
+			suspend_report_result(ops->suspend, error);
+		}
+		break;
+	case PM_EVENT_RESUME:
+		if (ops->resume) {
+			error = ops->resume(dev);
+			suspend_report_result(ops->resume, error);
+		}
+		break;
+#endif /* CONFIG_SUSPEND */
+#ifdef CONFIG_HIBERNATION
+	case PM_EVENT_FREEZE:
+	case PM_EVENT_QUIESCE:
+		if (ops->freeze) {
+			error = ops->freeze(dev);
+			suspend_report_result(ops->freeze, error);
+		}
+		break;
+	case PM_EVENT_HIBERNATE:
+		if (ops->poweroff) {
+			error = ops->poweroff(dev);
+			suspend_report_result(ops->poweroff, error);
+		}
+		break;
+	case PM_EVENT_THAW:
+	case PM_EVENT_RECOVER:
+		if (ops->thaw) {
+			error = ops->thaw(dev);
+			suspend_report_result(ops->thaw, error);
+		}
+		break;
+	case PM_EVENT_RESTORE:
+		if (ops->restore) {
+			error = ops->restore(dev);
+			suspend_report_result(ops->restore, error);
+		}
+		break;
+#endif /* CONFIG_HIBERNATION */
+	default:
+		error = -EINVAL;
+	}
+	return error;
+}
+
+/**
+ *	pm_noirq_op - execute the PM operation appropiate for given PM event
+ *	@dev:	Device.
+ *	@ops:	PM operations to choose from.
+ *	@state: PM transition of the system being carried out.
+ *
+ *	The operation is executed with interrupts disabled by the only remaining
+ *	functional CPU in the system.
+ */
+static int pm_noirq_op(struct device *dev, struct pm_ext_ops *ops,
+			pm_message_t state)
+{
+	int error = 0;
+
+	switch (state.event) {
+#ifdef CONFIG_SUSPEND
+	case PM_EVENT_SUSPEND:
+		if (ops->suspend_noirq) {
+			error = ops->suspend_noirq(dev);
+			suspend_report_result(ops->suspend_noirq, error);
+		}
+		break;
+	case PM_EVENT_RESUME:
+		if (ops->resume_noirq) {
+			error = ops->resume_noirq(dev);
+			suspend_report_result(ops->resume_noirq, error);
+		}
+		break;
+#endif /* CONFIG_SUSPEND */
+#ifdef CONFIG_HIBERNATION
+	case PM_EVENT_FREEZE:
+	case PM_EVENT_QUIESCE:
+		if (ops->freeze_noirq) {
+			error = ops->freeze_noirq(dev);
+			suspend_report_result(ops->freeze_noirq, error);
+		}
+		break;
+	case PM_EVENT_HIBERNATE:
+		if (ops->poweroff_noirq) {
+			error = ops->poweroff_noirq(dev);
+			suspend_report_result(ops->poweroff_noirq, error);
+		}
+		break;
+	case PM_EVENT_THAW:
+	case PM_EVENT_RECOVER:
+		if (ops->thaw_noirq) {
+			error = ops->thaw_noirq(dev);
+			suspend_report_result(ops->thaw_noirq, error);
+		}
+		break;
+	case PM_EVENT_RESTORE:
+		if (ops->restore_noirq) {
+			error = ops->restore_noirq(dev);
+			suspend_report_result(ops->restore_noirq, error);
+		}
+		break;
+#endif /* CONFIG_HIBERNATION */
+	default:
+		error = -EINVAL;
+	}
+	return error;
+}
+
+static char *pm_verb(int event)
+{
+	switch (event) {
+	case PM_EVENT_SUSPEND:
+		return "suspend";
+	case PM_EVENT_RESUME:
+		return "resume";
+	case PM_EVENT_FREEZE:
+		return "freeze";
+	case PM_EVENT_QUIESCE:
+		return "quiesce";
+	case PM_EVENT_HIBERNATE:
+		return "hibernate";
+	case PM_EVENT_THAW:
+		return "thaw";
+	case PM_EVENT_RESTORE:
+		return "restore";
+	default:
+		return "(unknown PM event)";
+	}
+}
+
+static void pm_dev_dbg(struct device *dev, pm_message_t state, char *info)
+{
+	dev_dbg(dev, "%s%s%s\n", info, pm_verb(state.event),
+		((state.event & PM_EVENT_SLEEP) && device_may_wakeup(dev)) ?
+		", may wakeup" : "");
+}
+
 /*------------------------- Resume routines -------------------------*/
 
 /**
- *	resume_device_early - Power on one device (early resume).
+ *	resume_device_noirq - Power on one device (early resume).
  *	@dev:	Device.
+ *	@state: PM transition of the system being carried out.
  *
  *	Must be called with interrupts disabled.
  */
-static int resume_device_early(struct device *dev)
+static int resume_device_noirq(struct device *dev, pm_message_t state)
 {
 	int error = 0;
 
 	TRACE_DEVICE(dev);
 	TRACE_RESUME(0);
 
-	if (dev->bus && dev->bus->resume_early) {
-		dev_dbg(dev, "EARLY resume\n");
+	if (!dev->bus)
+		goto End;
+
+	if (dev->bus->pm) {
+		pm_dev_dbg(dev, state, "EARLY ");
+		error = pm_noirq_op(dev, dev->bus->pm, state);
+	} else if (dev->bus->resume_early) {
+		pm_dev_dbg(dev, state, "legacy EARLY ");
 		error = dev->bus->resume_early(dev);
 	}
-
+ End:
 	TRACE_RESUME(error);
 	return error;
 }
 
 /**
  *	dpm_power_up - Power on all regular (non-sysdev) devices.
+ *	@state: PM transition of the system being carried out.
  *
- *	Walk the dpm_off_irq list and power each device up. This
- *	is used for devices that required they be powered down with
- *	interrupts disabled. As devices are powered on, they are moved
- *	to the dpm_off list.
+ *	Execute the appropriate "noirq resume" callback for all devices marked
+ *	as DPM_OFF_IRQ.
  *
  *	Must be called with interrupts disabled and only one CPU running.
  */
-static void dpm_power_up(void)
+static void dpm_power_up(pm_message_t state)
 {
+	struct device *dev;
 
-	while (!list_empty(&dpm_off_irq)) {
-		struct list_head *entry = dpm_off_irq.next;
-		struct device *dev = to_device(entry);
-
-		list_move_tail(entry, &dpm_off);
-		resume_device_early(dev);
+	list_for_each_entry(dev, &dpm_list, power.entry) {
+		if (dev->parent && dev->parent->power.status == DPM_INVALID) {
+			dev->power.status = DPM_INVALID;
+		} else if (dev->power.status > DPM_OFF) {
+			int error;
+
+			dev->power.status = DPM_OFF;
+			error = resume_device_noirq(dev, state);
+			if (error)
+				dev->power.status = DPM_INVALID;
+		}
 	}
 }
 
 /**
  *	device_power_up - Turn on all devices that need special attention.
+ *	@state: PM transition of the system being carried out.
  *
  *	Power on system devices, then devices that required we shut them down
  *	with interrupts disabled.
  *
  *	Must be called with interrupts disabled.
  */
-void device_power_up(void)
+void device_power_up(pm_message_t state)
 {
 	sysdev_resume();
-	dpm_power_up();
+	dpm_power_up(state);
 }
 EXPORT_SYMBOL_GPL(device_power_up);
 
 /**
  *	resume_device - Restore state for one device.
  *	@dev:	Device.
- *
+ *	@state: PM transition of the system being carried out.
  */
-static int resume_device(struct device *dev)
+static int resume_device(struct device *dev, pm_message_t state)
 {
 	int error = 0;
 
@@ -178,21 +364,40 @@ static int resume_device(struct device *
 
 	down(&dev->sem);
 
-	if (dev->bus && dev->bus->resume) {
-		dev_dbg(dev,"resuming\n");
-		error = dev->bus->resume(dev);
+	if (dev->bus) {
+		if (dev->bus->pm) {
+			pm_dev_dbg(dev, state, "");
+			error = pm_op(dev, &dev->bus->pm->base, state);
+		} else if (dev->bus->resume) {
+			pm_dev_dbg(dev, state, "legacy ");
+			error = dev->bus->resume(dev);
+		}
+		if (error)
+			goto End;
 	}
 
-	if (!error && dev->type && dev->type->resume) {
-		dev_dbg(dev,"resuming\n");
-		error = dev->type->resume(dev);
+	if (dev->type) {
+		if (dev->type->pm) {
+			pm_dev_dbg(dev, state, "type ");
+			error = pm_op(dev, dev->type->pm, state);
+		} else if (dev->type->resume) {
+			pm_dev_dbg(dev, state, "legacy type ");
+			error = dev->type->resume(dev);
+		}
+		if (error)
+			goto End;
 	}
 
-	if (!error && dev->class && dev->class->resume) {
-		dev_dbg(dev,"class resume\n");
-		error = dev->class->resume(dev);
+	if (dev->class) {
+		if (dev->class->pm) {
+			pm_dev_dbg(dev, state, "class ");
+			error = pm_op(dev, dev->class->pm, state);
+		} else if (dev->class->resume) {
+			pm_dev_dbg(dev, state, "legacy class ");
+			error = dev->class->resume(dev);
+		}
 	}
-
+ End:
 	up(&dev->sem);
 
 	TRACE_RESUME(error);
@@ -201,78 +406,163 @@ static int resume_device(struct device *
 
 /**
  *	dpm_resume - Resume every device.
+ *	@state: PM transition of the system being carried out.
  *
- *	Resume the devices that have either not gone through
- *	the late suspend, or that did go through it but also
- *	went through the early resume.
+ *	Execute the appropriate "resume" callback for all devices the status of
+ *	which indicates that they are inactive.
+ */
+static void dpm_resume(pm_message_t state)
+{
+	struct list_head list;
+
+	INIT_LIST_HEAD(&list);
+	mutex_lock(&dpm_list_mtx);
+	transition_started = false;
+	while (!list_empty(&dpm_list)) {
+		struct device *dev = to_device(dpm_list.next);
+
+		get_device(dev);
+		if (dev->parent && dev->parent->power.status == DPM_INVALID) {
+			dev->power.status = DPM_INVALID;
+		} else if (dev->power.status >= DPM_OFF) {
+			int error;
+
+			dev->power.status = DPM_RESUMING;
+			mutex_unlock(&dpm_list_mtx);
+
+			error = resume_device(dev, state);
+
+			mutex_lock(&dpm_list_mtx);
+			if (error)
+				dev->power.status = DPM_INVALID;
+		} else if (dev->power.status == DPM_SUSPENDING) {
+			/* Allow new children of the device to be registered */
+			dev->power.status = DPM_RESUMING;
+		}
+		if (!list_empty(&dev->power.entry))
+			list_move_tail(&dev->power.entry, &list);
+		put_device(dev);
+	}
+	list_splice(&list, &dpm_list);
+	mutex_unlock(&dpm_list_mtx);
+}
+
+/**
+ *	complete_device - Complete a PM transition for given device
+ *	@dev:	Device.
+ *	@state: PM transition of the system being carried out.
+ */
+static void complete_device(struct device *dev, pm_message_t state)
+{
+	down(&dev->sem);
+
+	if (dev->class && dev->class->pm && dev->class->pm->complete) {
+		pm_dev_dbg(dev, state, "completing class ");
+		dev->class->pm->complete(dev);
+	}
+
+	if (dev->type && dev->type->pm && dev->type->pm->complete) {
+		pm_dev_dbg(dev, state, "completing type ");
+		dev->type->pm->complete(dev);
+	}
+
+	if (dev->bus && dev->bus->pm && dev->bus->pm->base.complete) {
+		pm_dev_dbg(dev, state, "completing ");
+		dev->bus->pm->base.complete(dev);
+	}
+
+	up(&dev->sem);
+}
+
+/**
+ *	dpm_complete - Complete a PM transition for all devices.
+ *	@state: PM transition of the system being carried out.
  *
- *	Take devices from the dpm_off_list, resume them,
- *	and put them on the dpm_locked list.
+ *	Execute the ->complete() callbacks for all devices that are not marked
+ *	as DPM_ON.
  */
-static void dpm_resume(void)
+static void dpm_complete(pm_message_t state)
 {
+	struct list_head list;
+
+	INIT_LIST_HEAD(&list);
 	mutex_lock(&dpm_list_mtx);
-	all_sleeping = false;
-	while(!list_empty(&dpm_off)) {
-		struct list_head *entry = dpm_off.next;
-		struct device *dev = to_device(entry);
+	while (!list_empty(&dpm_list)) {
+		struct device *dev = to_device(dpm_list.prev);
 
-		list_move_tail(entry, &dpm_active);
-		dev->power.sleeping = false;
-		mutex_unlock(&dpm_list_mtx);
-		resume_device(dev);
-		mutex_lock(&dpm_list_mtx);
+		get_device(dev);
+		if (dev->power.status > DPM_ON) {
+			dev->power.status = DPM_ON;
+			mutex_unlock(&dpm_list_mtx);
+
+			complete_device(dev, state);
+
+			mutex_lock(&dpm_list_mtx);
+		}
+		if (!list_empty(&dev->power.entry))
+			list_move(&dev->power.entry, &list);
+		put_device(dev);
 	}
+	list_splice(&list, &dpm_list);
 	mutex_unlock(&dpm_list_mtx);
 }
 
 /**
  *	device_resume - Restore state of each device in system.
+ *	@state: PM transition of the system being carried out.
  *
  *	Resume all the devices, unlock them all, and allow new
  *	devices to be registered once again.
  */
-void device_resume(void)
+void device_resume(pm_message_t state)
 {
 	might_sleep();
-	dpm_resume();
+	dpm_resume(state);
+	dpm_complete(state);
 }
 EXPORT_SYMBOL_GPL(device_resume);
 
 
 /*------------------------- Suspend routines -------------------------*/
 
-static inline char *suspend_verb(u32 event)
+/**
+ *	resume_event - return a PM message representing the resume event
+ *	               corresponding to given sleep state.
+ *	@sleep_state: PM message representing a sleep state.
+ */
+static pm_message_t resume_event(pm_message_t sleep_state)
 {
-	switch (event) {
-	case PM_EVENT_SUSPEND:	return "suspend";
-	case PM_EVENT_FREEZE:	return "freeze";
-	case PM_EVENT_PRETHAW:	return "prethaw";
-	default:		return "(unknown suspend event)";
+	switch (sleep_state.event) {
+	case PM_EVENT_SUSPEND:
+		return PMSG_RESUME;
+	case PM_EVENT_FREEZE:
+	case PM_EVENT_QUIESCE:
+		return PMSG_RECOVER;
+	case PM_EVENT_HIBERNATE:
+		return PMSG_RESTORE;
 	}
-}
-
-static void
-suspend_device_dbg(struct device *dev, pm_message_t state, char *info)
-{
-	dev_dbg(dev, "%s%s%s\n", info, suspend_verb(state.event),
-		((state.event == PM_EVENT_SUSPEND) && device_may_wakeup(dev)) ?
-		", may wakeup" : "");
+	return PMSG_ON;
 }
 
 /**
- *	suspend_device_late - Shut down one device (late suspend).
+ *	suspend_device_noirq - Shut down one device (late suspend).
  *	@dev:	Device.
- *	@state:	Power state device is entering.
+ *	@state: PM transition of the system being carried out.
  *
  *	This is called with interrupts off and only a single CPU running.
  */
-static int suspend_device_late(struct device *dev, pm_message_t state)
+static int suspend_device_noirq(struct device *dev, pm_message_t state)
 {
 	int error = 0;
 
-	if (dev->bus && dev->bus->suspend_late) {
-		suspend_device_dbg(dev, state, "LATE ");
+	if (!dev->bus)
+		return 0;
+
+	if (dev->bus->pm) {
+		pm_dev_dbg(dev, state, "LATE ");
+		error = pm_noirq_op(dev, dev->bus->pm, state);
+	} else if (dev->bus->suspend_late) {
+		pm_dev_dbg(dev, state, "legacy LATE ");
 		error = dev->bus->suspend_late(dev, state);
 		suspend_report_result(dev->bus->suspend_late, error);
 	}
@@ -281,37 +571,32 @@ static int suspend_device_late(struct de
 
 /**
  *	device_power_down - Shut down special devices.
- *	@state:		Power state to enter.
+ *	@state: PM transition of the system being carried out.
  *
- *	Power down devices that require interrupts to be disabled
- *	and move them from the dpm_off list to the dpm_off_irq list.
+ *	Power down devices that require interrupts to be disabled.
  *	Then power down system devices.
  *
  *	Must be called with interrupts disabled and only one CPU running.
  */
 int device_power_down(pm_message_t state)
 {
+	struct device *dev;
 	int error = 0;
 
-	while (!list_empty(&dpm_off)) {
-		struct list_head *entry = dpm_off.prev;
-		struct device *dev = to_device(entry);
-
-		error = suspend_device_late(dev, state);
+	list_for_each_entry_reverse(dev, &dpm_list, power.entry) {
+		error = suspend_device_noirq(dev, state);
 		if (error) {
 			printk(KERN_ERR "Could not power down device %s: "
 					"error %d\n",
 					kobject_name(&dev->kobj), error);
 			break;
 		}
-		if (!list_empty(&dev->power.entry))
-			list_move(&dev->power.entry, &dpm_off_irq);
+		dev->power.status = DPM_OFF_IRQ;
 	}
-
 	if (!error)
 		error = sysdev_suspend(state);
 	if (error)
-		dpm_power_up();
+		dpm_power_up(resume_event(state));
 	return error;
 }
 EXPORT_SYMBOL_GPL(device_power_down);
@@ -319,7 +604,7 @@ EXPORT_SYMBOL_GPL(device_power_down);
 /**
  *	suspend_device - Save state of one device.
  *	@dev:	Device.
- *	@state:	Power state device is entering.
+ *	@state: PM transition of the system being carried out.
  */
 static int suspend_device(struct device *dev, pm_message_t state)
 {
@@ -327,29 +612,43 @@ static int suspend_device(struct device 
 
 	down(&dev->sem);
 
-	if (dev->power.power_state.event) {
-		dev_dbg(dev, "PM: suspend %d-->%d\n",
-			dev->power.power_state.event, state.event);
-	}
-
-	if (dev->class && dev->class->suspend) {
-		suspend_device_dbg(dev, state, "class ");
-		error = dev->class->suspend(dev, state);
-		suspend_report_result(dev->class->suspend, error);
+	if (dev->class) {
+		if (dev->class->pm) {
+			pm_dev_dbg(dev, state, "class ");
+			error = pm_op(dev, dev->class->pm, state);
+		} else if (dev->class->suspend) {
+			pm_dev_dbg(dev, state, "legacy class ");
+			error = dev->class->suspend(dev, state);
+			suspend_report_result(dev->class->suspend, error);
+		}
+		if (error)
+			goto End;
 	}
 
-	if (!error && dev->type && dev->type->suspend) {
-		suspend_device_dbg(dev, state, "type ");
-		error = dev->type->suspend(dev, state);
-		suspend_report_result(dev->type->suspend, error);
+	if (dev->type) {
+		if (dev->type->pm) {
+			pm_dev_dbg(dev, state, "type ");
+			error = pm_op(dev, dev->type->pm, state);
+		} else if (dev->type->suspend) {
+			pm_dev_dbg(dev, state, "legacy type ");
+			error = dev->type->suspend(dev, state);
+			suspend_report_result(dev->type->suspend, error);
+		}
+		if (error)
+			goto End;
 	}
 
-	if (!error && dev->bus && dev->bus->suspend) {
-		suspend_device_dbg(dev, state, "");
-		error = dev->bus->suspend(dev, state);
-		suspend_report_result(dev->bus->suspend, error);
+	if (dev->bus) {
+		if (dev->bus->pm) {
+			pm_dev_dbg(dev, state, "");
+			error = pm_op(dev, &dev->bus->pm->base, state);
+		} else if (dev->bus->suspend) {
+			pm_dev_dbg(dev, state, "legacy ");
+			error = dev->bus->suspend(dev, state);
+			suspend_report_result(dev->bus->suspend, error);
+		}
 	}
-
+ End:
 	up(&dev->sem);
 
 	return error;
@@ -357,67 +656,147 @@ static int suspend_device(struct device 
 
 /**
  *	dpm_suspend - Suspend every device.
- *	@state:	Power state to put each device in.
+ *	@state: PM transition of the system being carried out.
  *
- *	Walk the dpm_locked list.  Suspend each device and move it
- *	to the dpm_off list.
- *
- *	(For historical reasons, if it returns -EAGAIN, that used to mean
- *	that the device would be called again with interrupts disabled.
- *	These days, we use the "suspend_late()" callback for that, so we
- *	print a warning and consider it an error).
+ *	Execute the appropriate "suspend" callbacks for all devices.
  */
 static int dpm_suspend(pm_message_t state)
 {
+	struct list_head list;
 	int error = 0;
 
+	INIT_LIST_HEAD(&list);
 	mutex_lock(&dpm_list_mtx);
-	while (!list_empty(&dpm_active)) {
-		struct list_head *entry = dpm_active.prev;
-		struct device *dev = to_device(entry);
-
-		WARN_ON(dev->parent && dev->parent->power.sleeping);
+	while (!list_empty(&dpm_list)) {
+		struct device *dev = to_device(dpm_list.prev);
 
-		dev->power.sleeping = true;
+		get_device(dev);
 		mutex_unlock(&dpm_list_mtx);
+
 		error = suspend_device(dev, state);
+
 		mutex_lock(&dpm_list_mtx);
 		if (error) {
 			printk(KERN_ERR "Could not suspend device %s: "
-					"error %d%s\n",
-					kobject_name(&dev->kobj),
-					error,
-					(error == -EAGAIN ?
-					" (please convert to suspend_late)" :
-					""));
-			dev->power.sleeping = false;
+				"error %d\n", kobject_name(&dev->kobj), error);
+			put_device(dev);
 			break;
 		}
+		dev->power.status = DPM_OFF;
 		if (!list_empty(&dev->power.entry))
-			list_move(&dev->power.entry, &dpm_off);
+			list_move(&dev->power.entry, &list);
+		put_device(dev);
 	}
-	if (!error)
-		all_sleeping = true;
+	list_splice(&list, dpm_list.prev);
 	mutex_unlock(&dpm_list_mtx);
+	return error;
+}
+
+/**
+ *	prepare_device - Execute the ->prepare() callback(s) for given device.
+ *	@dev:	Device.
+ *	@state: PM transition of the system being carried out.
+ */
+static int prepare_device(struct device *dev, pm_message_t state)
+{
+	int error = 0;
+
+	down(&dev->sem);
+
+	if (dev->bus && dev->bus->pm && dev->bus->pm->base.prepare) {
+		pm_dev_dbg(dev, state, "preparing ");
+		error = dev->bus->pm->base.prepare(dev);
+		suspend_report_result(dev->bus->pm->base.prepare, error);
+		if (error)
+			goto End;
+	}
+
+	if (dev->type && dev->type->pm && dev->type->pm->prepare) {
+		pm_dev_dbg(dev, state, "preparing type ");
+		error = dev->type->pm->prepare(dev);
+		suspend_report_result(dev->type->pm->prepare, error);
+		if (error)
+			goto End;
+	}
+
+	if (dev->class && dev->class->pm && dev->class->pm->prepare) {
+		pm_dev_dbg(dev, state, "preparing class ");
+		error = dev->class->pm->prepare(dev);
+		suspend_report_result(dev->class->pm->prepare, error);
+	}
+ End:
+	up(&dev->sem);
 
 	return error;
 }
 
 /**
+ *	dpm_prepare - Prepare all devices for a PM transition.
+ *	@state: PM transition of the system being carried out.
+ *
+ *	Execute the ->prepare() callback for all devices.
+ */
+static int dpm_prepare(pm_message_t state)
+{
+	struct list_head list;
+	int error = 0;
+
+	INIT_LIST_HEAD(&list);
+	mutex_lock(&dpm_list_mtx);
+	transition_started = true;
+	while (!list_empty(&dpm_list)) {
+		struct device *dev = to_device(dpm_list.next);
+
+		get_device(dev);
+		if (dev->power.status == DPM_INVALID) {
+			put_device(dev);
+			error = -EINVAL;
+			break;
+		}
+		mutex_unlock(&dpm_list_mtx);
+
+		error = prepare_device(dev, state);
+
+		mutex_lock(&dpm_list_mtx);
+		if (error) {
+			if (dev->power.status != DPM_INVALID)
+				dev->power.status = DPM_ON;
+			if (error == -EAGAIN) {
+				put_device(dev);
+				continue;
+			}
+			printk(KERN_ERR "Could not prepare device %s "
+				"for suspend: error %d\n",
+				kobject_name(&dev->kobj), error);
+			put_device(dev);
+			break;
+		}
+		dev->power.status = DPM_SUSPENDING;
+		if (!list_empty(&dev->power.entry))
+			list_move_tail(&dev->power.entry, &list);
+		put_device(dev);
+	}
+	list_splice(&list, &dpm_list);
+	mutex_unlock(&dpm_list_mtx);
+	return error;
+}
+
+/**
  *	device_suspend - Save state and stop all devices in system.
- *	@state: new power management state
+ *	@state: PM transition of the system being carried out.
  *
- *	Prevent new devices from being registered, then lock all devices
- *	and suspend them.
+ *	Prepare and suspend all devices.
  */
 int device_suspend(pm_message_t state)
 {
 	int error;
 
 	might_sleep();
-	error = dpm_suspend(state);
+	error = dpm_prepare(state);
+	if (!error)
+		error = dpm_suspend(state);
 	if (error)
-		device_resume();
+		device_resume(resume_event(state));
 	return error;
 }
 EXPORT_SYMBOL_GPL(device_suspend);
Index: linux-2.6/include/linux/device.h
===================================================================
--- linux-2.6.orig/include/linux/device.h
+++ linux-2.6/include/linux/device.h
@@ -69,6 +69,8 @@ struct bus_type {
 	int (*resume_early)(struct device *dev);
 	int (*resume)(struct device *dev);
 
+	struct pm_ext_ops *pm;
+
 	struct bus_type_private *p;
 };
 
@@ -132,6 +134,8 @@ struct device_driver {
 	int (*resume) (struct device *dev);
 	struct attribute_group **groups;
 
+	struct pm_ops *pm;
+
 	struct driver_private *p;
 };
 
@@ -202,6 +206,8 @@ struct class {
 
 	int (*suspend)(struct device *dev, pm_message_t state);
 	int (*resume)(struct device *dev);
+
+	struct pm_ops *pm;
 };
 
 extern int __must_check class_register(struct class *class);
@@ -345,8 +351,11 @@ struct device_type {
 	struct attribute_group **groups;
 	int (*uevent)(struct device *dev, struct kobj_uevent_env *env);
 	void (*release)(struct device *dev);
+
 	int (*suspend)(struct device *dev, pm_message_t state);
 	int (*resume)(struct device *dev);
+
+	struct pm_ops *pm;
 };
 
 /* interface for exporting device attributes */
Index: linux-2.6/kernel/power/disk.c
===================================================================
--- linux-2.6.orig/kernel/power/disk.c
+++ linux-2.6/kernel/power/disk.c
@@ -193,6 +193,7 @@ static int create_image(int platform_mod
 	if (error)
 		return error;
 
+	device_pm_lock();
 	local_irq_disable();
 	/* At this point, device_suspend() has been called, but *not*
 	 * device_power_down(). We *must* call device_power_down() now.
@@ -224,9 +225,10 @@ static int create_image(int platform_mod
 	/* NOTE:  device_power_up() is just a resume() for devices
 	 * that suspended with irqs off ... no overall powerup.
 	 */
-	device_power_up();
+	device_power_up(in_suspend ? PMSG_RECOVER : PMSG_RESTORE);
  Enable_irqs:
 	local_irq_enable();
+	device_pm_unlock();
 	return error;
 }
 
@@ -280,7 +282,7 @@ int hibernation_snapshot(int platform_mo
  Finish:
 	platform_finish(platform_mode);
  Resume_devices:
-	device_resume();
+	device_resume(in_suspend ? PMSG_RECOVER : PMSG_RESTORE);
  Resume_console:
 	resume_console();
  Close:
@@ -300,8 +302,9 @@ static int resume_target_kernel(void)
 {
 	int error;
 
+	device_pm_lock();
 	local_irq_disable();
-	error = device_power_down(PMSG_PRETHAW);
+	error = device_power_down(PMSG_QUIESCE);
 	if (error) {
 		printk(KERN_ERR "PM: Some devices failed to power down, "
 			"aborting resume\n");
@@ -329,9 +332,10 @@ static int resume_target_kernel(void)
 	swsusp_free();
 	restore_processor_state();
 	touch_softlockup_watchdog();
-	device_power_up();
+	device_power_up(PMSG_THAW);
  Enable_irqs:
 	local_irq_enable();
+	device_pm_unlock();
 	return error;
 }
 
@@ -350,7 +354,7 @@ int hibernation_restore(int platform_mod
 
 	pm_prepare_console();
 	suspend_console();
-	error = device_suspend(PMSG_PRETHAW);
+	error = device_suspend(PMSG_QUIESCE);
 	if (error)
 		goto Finish;
 
@@ -362,7 +366,7 @@ int hibernation_restore(int platform_mod
 		enable_nonboot_cpus();
 	}
 	platform_restore_cleanup(platform_mode);
-	device_resume();
+	device_resume(PMSG_RECOVER);
  Finish:
 	resume_console();
 	pm_restore_console();
@@ -403,6 +407,7 @@ int hibernation_platform_enter(void)
 	if (error)
 		goto Finish;
 
+	device_pm_lock();
 	local_irq_disable();
 	error = device_power_down(PMSG_HIBERNATE);
 	if (!error) {
@@ -411,6 +416,7 @@ int hibernation_platform_enter(void)
 		while (1);
 	}
 	local_irq_enable();
+	device_pm_unlock();
 
 	/*
 	 * We don't need to reenable the nonboot CPUs or resume consoles, since
@@ -419,7 +425,7 @@ int hibernation_platform_enter(void)
  Finish:
 	hibernation_ops->finish();
  Resume_devices:
-	device_resume();
+	device_resume(PMSG_RESTORE);
  Resume_console:
 	resume_console();
  Close:
Index: linux-2.6/kernel/power/main.c
===================================================================
--- linux-2.6.orig/kernel/power/main.c
+++ linux-2.6/kernel/power/main.c
@@ -228,6 +228,7 @@ static int suspend_enter(suspend_state_t
 {
 	int error = 0;
 
+	device_pm_lock();
 	arch_suspend_disable_irqs();
 	BUG_ON(!irqs_disabled());
 
@@ -239,10 +240,11 @@ static int suspend_enter(suspend_state_t
 	if (!suspend_test(TEST_CORE))
 		error = suspend_ops->enter(state);
 
-	device_power_up();
+	device_power_up(PMSG_RESUME);
  Done:
 	arch_suspend_enable_irqs();
 	BUG_ON(irqs_disabled());
+	device_pm_unlock();
 	return error;
 }
 
@@ -291,7 +293,7 @@ int suspend_devices_and_enter(suspend_st
 	if (suspend_ops->finish)
 		suspend_ops->finish();
  Resume_devices:
-	device_resume();
+	device_resume(PMSG_RESUME);
  Resume_console:
 	resume_console();
  Close:
Index: linux-2.6/arch/x86/kernel/apm_32.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/apm_32.c
+++ linux-2.6/arch/x86/kernel/apm_32.c
@@ -1208,9 +1208,9 @@ static int suspend(int vetoable)
 	if (err != APM_SUCCESS)
 		apm_error("suspend", err);
 	err = (err == APM_SUCCESS) ? 0 : -EIO;
-	device_power_up();
+	device_power_up(PMSG_RESUME);
 	local_irq_enable();
-	device_resume();
+	device_resume(PMSG_RESUME);
 	queue_event(APM_NORMAL_RESUME, NULL);
  out:
 	spin_lock(&user_list_lock);
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
@@ -4,7 +4,7 @@
  * main.c
  */
 
-extern struct list_head dpm_active;	/* The active device list */
+extern struct list_head dpm_list;	/* The active device list */
 
 static inline struct device *to_device(struct list_head *entry)
 {
Index: linux-2.6/drivers/base/power/trace.c
===================================================================
--- linux-2.6.orig/drivers/base/power/trace.c
+++ linux-2.6/drivers/base/power/trace.c
@@ -188,9 +188,9 @@ static int show_file_hash(unsigned int v
 static int show_dev_hash(unsigned int value)
 {
 	int match = 0;
-	struct list_head * entry = dpm_active.prev;
+	struct list_head *entry = dpm_list.prev;
 
-	while (entry != &dpm_active) {
+	while (entry != &dpm_list) {
 		struct device * dev = to_device(entry);
 		unsigned int hash = hash_string(DEVSEED, dev->bus_id, DEVHASH);
 		if (hash == value) {

[RFC][PATCH 2/3] PM: New suspend and hibernation callbacks for platform bus type (rev. 3)

[Rafael J. Wysocki]

From: Rafael J. Wysocki <rjw@sisk.pl>

Implement new suspend and hibernation callbacks for the platform bus
type.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
---
 drivers/base/platform.c         |  296 ++++++++++++++++++++++++++++++++++++++--
 include/linux/platform_device.h |    1 
 2 files changed, 289 insertions(+), 8 deletions(-)

Index: linux-2.6/include/linux/platform_device.h
===================================================================
--- linux-2.6.orig/include/linux/platform_device.h
+++ linux-2.6/include/linux/platform_device.h
@@ -53,6 +53,7 @@ struct platform_driver {
 	int (*suspend_late)(struct platform_device *, pm_message_t state);
 	int (*resume_early)(struct platform_device *);
 	int (*resume)(struct platform_device *);
+	struct pm_ext_ops *pm;
 	struct device_driver driver;
 };
 
Index: linux-2.6/drivers/base/platform.c
===================================================================
--- linux-2.6.orig/drivers/base/platform.c
+++ linux-2.6/drivers/base/platform.c
@@ -453,6 +453,8 @@ int platform_driver_register(struct plat
 		drv->driver.suspend = platform_drv_suspend;
 	if (drv->resume)
 		drv->driver.resume = platform_drv_resume;
+	if (drv->pm)
+		drv->driver.pm = &drv->pm->base;
 	return driver_register(&drv->driver);
 }
 EXPORT_SYMBOL_GPL(platform_driver_register);
@@ -560,7 +562,9 @@ static int platform_match(struct device 
 	return (strncmp(pdev->name, drv->name, BUS_ID_SIZE) == 0);
 }
 
-static int platform_suspend(struct device *dev, pm_message_t mesg)
+#ifdef CONFIG_PM_SLEEP
+
+static int platform_legacy_suspend(struct device *dev, pm_message_t mesg)
 {
 	int ret = 0;
 
@@ -570,7 +574,7 @@ static int platform_suspend(struct devic
 	return ret;
 }
 
-static int platform_suspend_late(struct device *dev, pm_message_t mesg)
+static int platform_legacy_suspend_late(struct device *dev, pm_message_t mesg)
 {
 	struct platform_driver *drv = to_platform_driver(dev->driver);
 	struct platform_device *pdev;
@@ -583,7 +587,7 @@ static int platform_suspend_late(struct 
 	return ret;
 }
 
-static int platform_resume_early(struct device *dev)
+static int platform_legacy_resume_early(struct device *dev)
 {
 	struct platform_driver *drv = to_platform_driver(dev->driver);
 	struct platform_device *pdev;
@@ -596,7 +600,7 @@ static int platform_resume_early(struct 
 	return ret;
 }
 
-static int platform_resume(struct device *dev)
+static int platform_legacy_resume(struct device *dev)
 {
 	int ret = 0;
 
@@ -606,15 +610,291 @@ static int platform_resume(struct device
 	return ret;
 }
 
+static int platform_pm_prepare(struct device *dev)
+{
+	struct device_driver *drv = dev->driver;
+	int ret = 0;
+
+	if (drv && drv->pm && drv->pm->prepare)
+		ret = drv->pm->prepare(dev);
+
+	return ret;
+}
+
+static void platform_pm_complete(struct device *dev)
+{
+	struct device_driver *drv = dev->driver;
+
+	if (drv && drv->pm && drv->pm->complete)
+		drv->pm->complete(dev);
+}
+
+#ifdef CONFIG_SUSPEND
+
+static int platform_pm_suspend(struct device *dev)
+{
+	struct device_driver *drv = dev->driver;
+	int ret = 0;
+
+	if (drv && drv->pm) {
+		if (drv->pm->suspend)
+			ret = drv->pm->suspend(dev);
+	} else {
+		ret = platform_legacy_suspend(dev, PMSG_SUSPEND);
+	}
+
+	return ret;
+}
+
+static int platform_pm_suspend_noirq(struct device *dev)
+{
+	struct platform_driver *pdrv;
+	int ret = 0;
+
+	if (!dev->driver)
+		return 0;
+
+	pdrv = to_platform_driver(dev->driver);
+	if (pdrv->pm) {
+		if (pdrv->pm->suspend_noirq)
+			ret = pdrv->pm->suspend_noirq(dev);
+	} else {
+		ret = platform_legacy_suspend_late(dev, PMSG_SUSPEND);
+	}
+
+	return ret;
+}
+
+static int platform_pm_resume(struct device *dev)
+{
+	struct device_driver *drv = dev->driver;
+	int ret = 0;
+
+	if (drv && drv->pm) {
+		if (drv->pm->resume)
+			ret = drv->pm->resume(dev);
+	} else {
+		ret = platform_legacy_resume(dev);
+	}
+
+	return ret;
+}
+
+static int platform_pm_resume_noirq(struct device *dev)
+{
+	struct platform_driver *pdrv;
+	int ret = 0;
+
+	if (!dev->driver)
+		return 0;
+
+	pdrv = to_platform_driver(dev->driver);
+	if (pdrv->pm) {
+		if (pdrv->pm->resume_noirq)
+			ret = pdrv->pm->resume_noirq(dev);
+	} else {
+		ret = platform_legacy_resume_early(dev);
+	}
+
+	return ret;
+}
+
+#else /* !CONFIG_SUSPEND */
+
+#define platform_pm_suspend		NULL
+#define platform_pm_resume		NULL
+#define platform_pm_suspend_noirq	NULL
+#define platform_pm_resume_noirq	NULL
+
+#endif /* !CONFIG_SUSPEND */
+
+#ifdef CONFIG_HIBERNATION
+
+static int platform_pm_freeze(struct device *dev)
+{
+	struct device_driver *drv = dev->driver;
+	int ret = 0;
+
+	if (!drv)
+		return 0;
+
+	if (drv->pm) {
+		if (drv->pm->freeze)
+			ret = drv->pm->freeze(dev);
+	} else {
+		ret = platform_legacy_suspend_late(dev, PMSG_FREEZE);
+	}
+
+	return ret;
+}
+
+static int platform_pm_freeze_noirq(struct device *dev)
+{
+	struct platform_driver *pdrv;
+	int ret = 0;
+
+	if (!dev->driver)
+		return 0;
+
+	pdrv = to_platform_driver(dev->driver);
+	if (pdrv->pm) {
+		if (pdrv->pm->freeze_noirq)
+			ret = pdrv->pm->freeze_noirq(dev);
+	} else {
+		ret = platform_legacy_suspend(dev, PMSG_FREEZE);
+	}
+
+	return ret;
+}
+
+static int platform_pm_thaw(struct device *dev)
+{
+	struct device_driver *drv = dev->driver;
+	int ret = 0;
+
+	if (drv && drv->pm) {
+		if (drv->pm->thaw)
+			ret = drv->pm->thaw(dev);
+	} else {
+		ret = platform_legacy_resume(dev);
+	}
+
+	return ret;
+}
+
+static int platform_pm_thaw_noirq(struct device *dev)
+{
+	struct platform_driver *pdrv;
+	int ret = 0;
+
+	if (!dev->driver)
+		return 0;
+
+	pdrv = to_platform_driver(dev->driver);
+	if (pdrv->pm) {
+		if (pdrv->pm->thaw_noirq)
+			ret = pdrv->pm->thaw_noirq(dev);
+	} else {
+		ret = platform_legacy_resume_early(dev);
+	}
+
+	return ret;
+}
+
+static int platform_pm_poweroff(struct device *dev)
+{
+	struct device_driver *drv = dev->driver;
+	int ret = 0;
+
+	if (drv && drv->pm) {
+		if (drv->pm->poweroff)
+			ret = drv->pm->poweroff(dev);
+	} else {
+		ret = platform_legacy_suspend(dev, PMSG_HIBERNATE);
+	}
+
+	return ret;
+}
+
+static int platform_pm_poweroff_noirq(struct device *dev)
+{
+	struct platform_driver *pdrv;
+	int ret = 0;
+
+	if (!dev->driver)
+		return 0;
+
+	pdrv = to_platform_driver(dev->driver);
+	if (pdrv->pm) {
+		if (pdrv->pm->poweroff_noirq)
+			ret = pdrv->pm->poweroff_noirq(dev);
+	} else {
+		ret = platform_legacy_suspend_late(dev, PMSG_HIBERNATE);
+	}
+
+	return ret;
+}
+
+static int platform_pm_restore(struct device *dev)
+{
+	struct device_driver *drv = dev->driver;
+	int ret = 0;
+
+	if (drv && drv->pm) {
+		if (drv->pm->restore)
+			ret = drv->pm->restore(dev);
+	} else {
+		ret = platform_legacy_resume(dev);
+	}
+
+	return ret;
+}
+
+static int platform_pm_restore_noirq(struct device *dev)
+{
+	struct platform_driver *pdrv;
+	int ret = 0;
+
+	if (!dev->driver)
+		return 0;
+
+	pdrv = to_platform_driver(dev->driver);
+	if (pdrv->pm) {
+		if (pdrv->pm->restore_noirq)
+			ret = pdrv->pm->restore_noirq(dev);
+	} else {
+		ret = platform_legacy_resume_early(dev);
+	}
+
+	return ret;
+}
+
+#else /* !CONFIG_HIBERNATION */
+
+#define platform_pm_freeze		NULL
+#define platform_pm_thaw		NULL
+#define platform_pm_poweroff		NULL
+#define platform_pm_restore		NULL
+#define platform_pm_freeze_noirq	NULL
+#define platform_pm_thaw_noirq		NULL
+#define platform_pm_poweroff_noirq	NULL
+#define platform_pm_restore_noirq	NULL
+
+#endif /* !CONFIG_HIBERNATION */
+
+struct pm_ext_ops platform_pm_ops = {
+	.base = {
+		.prepare = platform_pm_prepare,
+		.complete = platform_pm_complete,
+		.suspend = platform_pm_suspend,
+		.resume = platform_pm_resume,
+		.freeze = platform_pm_freeze,
+		.thaw = platform_pm_thaw,
+		.poweroff = platform_pm_poweroff,
+		.restore = platform_pm_restore,
+	},
+	.suspend_noirq = platform_pm_suspend_noirq,
+	.resume_noirq = platform_pm_resume_noirq,
+	.freeze_noirq = platform_pm_freeze_noirq,
+	.thaw_noirq = platform_pm_thaw_noirq,
+	.poweroff_noirq = platform_pm_poweroff_noirq,
+	.restore_noirq = platform_pm_restore_noirq,
+};
+
+#define PLATFORM_PM_OPS_PTR	&platform_pm_ops
+
+#else /* !CONFIG_PM_SLEEP */
+
+#define PLATFORM_PM_OPS_PTR	NULL
+
+#endif /* !CONFIG_PM_SLEEP */
+
 struct bus_type platform_bus_type = {
 	.name		= "platform",
 	.dev_attrs	= platform_dev_attrs,
 	.match		= platform_match,
 	.uevent		= platform_uevent,
-	.suspend	= platform_suspend,
-	.suspend_late	= platform_suspend_late,
-	.resume_early	= platform_resume_early,
-	.resume		= platform_resume,
+	.pm		= PLATFORM_PM_OPS_PTR,
 };
 EXPORT_SYMBOL_GPL(platform_bus_type);
 

[RFC][PATCH 3/3] PM: New suspend and hibernation callbacks for PCI bus type (rev. 3)

[Rafael J. Wysocki]

From: Rafael J. Wysocki <rjw@sisk.pl>

Implement new suspend and hibernation callbacks for the PCI bus type.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
---
 drivers/pci/pci-driver.c |  371 ++++++++++++++++++++++++++++++++++++++++++-----
 include/linux/pci.h      |    2 
 2 files changed, 334 insertions(+), 39 deletions(-)

Index: linux-2.6/drivers/pci/pci-driver.c
===================================================================
--- linux-2.6.orig/drivers/pci/pci-driver.c
+++ linux-2.6/drivers/pci/pci-driver.c
@@ -271,7 +271,52 @@ static int pci_device_remove(struct devi
 	return 0;
 }
 
-static int pci_device_suspend(struct device * dev, pm_message_t state)
+static void pci_device_shutdown(struct device *dev)
+{
+	struct pci_dev *pci_dev = to_pci_dev(dev);
+	struct pci_driver *drv = pci_dev->driver;
+
+	if (drv && drv->shutdown)
+		drv->shutdown(pci_dev);
+}
+
+#ifdef CONFIG_PM_SLEEP
+
+/*
+ * Default "suspend" method for devices that have no driver provided suspend,
+ * or not even a driver at all.
+ */
+static void pci_default_pm_suspend(struct pci_dev *pci_dev)
+{
+	pci_save_state(pci_dev);
+	/*
+	 * mark its power state as "unknown", since we don't know if
+	 * e.g. the BIOS will change its device state when we suspend.
+	 */
+	if (pci_dev->current_state == PCI_D0)
+		pci_dev->current_state = PCI_UNKNOWN;
+}
+
+/*
+ * Default "resume" method for devices that have no driver provided resume,
+ * or not even a driver at all.
+ */
+static int pci_default_pm_resume(struct pci_dev *pci_dev)
+{
+	int retval = 0;
+
+	/* restore the PCI config space */
+	pci_restore_state(pci_dev);
+	/* if the device was enabled before suspend, reenable */
+	retval = pci_reenable_device(pci_dev);
+	/* if the device was busmaster before the suspend, make it busmaster again */
+	if (pci_dev->is_busmaster)
+		pci_set_master(pci_dev);
+
+	return retval;
+}
+
+static int pci_legacy_suspend(struct device * dev, pm_message_t state)
 {
 	struct pci_dev * pci_dev = to_pci_dev(dev);
 	struct pci_driver * drv = pci_dev->driver;
@@ -281,18 +326,12 @@ static int pci_device_suspend(struct dev
 		i = drv->suspend(pci_dev, state);
 		suspend_report_result(drv->suspend, i);
 	} else {
-		pci_save_state(pci_dev);
-		/*
-		 * mark its power state as "unknown", since we don't know if
-		 * e.g. the BIOS will change its device state when we suspend.
-		 */
-		if (pci_dev->current_state == PCI_D0)
-			pci_dev->current_state = PCI_UNKNOWN;
+		pci_default_pm_suspend(pci_dev);
 	}
 	return i;
 }
 
-static int pci_device_suspend_late(struct device * dev, pm_message_t state)
+static int pci_legacy_suspend_late(struct device * dev, pm_message_t state)
 {
 	struct pci_dev * pci_dev = to_pci_dev(dev);
 	struct pci_driver * drv = pci_dev->driver;
@@ -305,26 +344,7 @@ static int pci_device_suspend_late(struc
 	return i;
 }
 
-/*
- * Default resume method for devices that have no driver provided resume,
- * or not even a driver at all.
- */
-static int pci_default_resume(struct pci_dev *pci_dev)
-{
-	int retval = 0;
-
-	/* restore the PCI config space */
-	pci_restore_state(pci_dev);
-	/* if the device was enabled before suspend, reenable */
-	retval = pci_reenable_device(pci_dev);
-	/* if the device was busmaster before the suspend, make it busmaster again */
-	if (pci_dev->is_busmaster)
-		pci_set_master(pci_dev);
-
-	return retval;
-}
-
-static int pci_device_resume(struct device * dev)
+static int pci_legacy_resume(struct device * dev)
 {
 	int error;
 	struct pci_dev * pci_dev = to_pci_dev(dev);
@@ -333,11 +353,11 @@ static int pci_device_resume(struct devi
 	if (drv && drv->resume)
 		error = drv->resume(pci_dev);
 	else
-		error = pci_default_resume(pci_dev);
+		error = pci_default_pm_resume(pci_dev);
 	return error;
 }
 
-static int pci_device_resume_early(struct device * dev)
+static int pci_legacy_resume_early(struct device * dev)
 {
 	int error = 0;
 	struct pci_dev * pci_dev = to_pci_dev(dev);
@@ -350,15 +370,290 @@ static int pci_device_resume_early(struc
 	return error;
 }
 
-static void pci_device_shutdown(struct device *dev)
+static int pci_pm_prepare(struct device *dev)
+{
+	struct device_driver *drv = dev->driver;
+	int error = 0;
+
+	if (drv && drv->pm && drv->pm->prepare)
+		error = drv->pm->prepare(dev);
+
+	return error;
+}
+
+static void pci_pm_complete(struct device *dev)
+{
+	struct device_driver *drv = dev->driver;
+
+	if (drv && drv->pm && drv->pm->complete)
+		drv->pm->complete(dev);
+}
+
+#ifdef CONFIG_SUSPEND
+
+static int pci_pm_suspend(struct device *dev)
+{
+	struct pci_dev *pci_dev = to_pci_dev(dev);
+	struct device_driver *drv = dev->driver;
+	int error = 0;
+
+	if (drv && drv->pm) {
+		if (drv->pm->suspend) {
+			error = drv->pm->suspend(dev);
+			suspend_report_result(drv->pm->suspend, error);
+		} else {
+			pci_default_pm_suspend(pci_dev);
+		}
+	} else {
+		error = pci_legacy_suspend(dev, PMSG_SUSPEND);
+	}
+
+	return error;
+}
+
+static int pci_pm_suspend_noirq(struct device *dev)
 {
 	struct pci_dev *pci_dev = to_pci_dev(dev);
 	struct pci_driver *drv = pci_dev->driver;
+	int error = 0;
 
-	if (drv && drv->shutdown)
-		drv->shutdown(pci_dev);
+	if (drv && drv->pm) {
+		if (drv->pm->suspend_noirq) {
+			error = drv->pm->suspend_noirq(dev);
+			suspend_report_result(drv->pm->suspend_noirq, error);
+		}
+	} else {
+		error = pci_legacy_suspend_late(dev, PMSG_SUSPEND);
+	}
+
+	return error;
 }
 
+static int pci_pm_resume(struct device *dev)
+{
+	struct pci_dev *pci_dev = to_pci_dev(dev);
+	struct device_driver *drv = dev->driver;
+	int error;
+
+	if (drv && drv->pm) {
+		error = drv->pm->resume ? drv->pm->resume(dev) :
+			pci_default_pm_resume(pci_dev);
+	} else {
+		error = pci_legacy_resume(dev);
+	}
+
+	return error;
+}
+
+static int pci_pm_resume_noirq(struct device *dev)
+{
+	struct pci_dev *pci_dev = to_pci_dev(dev);
+	struct pci_driver *drv = pci_dev->driver;
+	int error = 0;
+
+	pci_fixup_device(pci_fixup_resume, pci_dev);
+
+	if (drv && drv->pm) {
+		if (drv->pm->resume_noirq)
+			error = drv->pm->resume_noirq(dev);
+	} else {
+		error = pci_legacy_resume_early(dev);
+	}
+
+	return error;
+}
+
+#else /* !CONFIG_SUSPEND */
+
+#define pci_pm_suspend		NULL
+#define pci_pm_suspend_noirq	NULL
+#define pci_pm_resume		NULL
+#define pci_pm_resume_noirq	NULL
+
+#endif /* !CONFIG_SUSPEND */
+
+#ifdef CONFIG_HIBERNATION
+
+static int pci_pm_freeze(struct device *dev)
+{
+	struct pci_dev *pci_dev = to_pci_dev(dev);
+	struct device_driver *drv = dev->driver;
+	int error = 0;
+
+	if (drv && drv->pm) {
+		if (drv->pm->freeze) {
+			error = drv->pm->freeze(dev);
+			suspend_report_result(drv->pm->freeze, error);
+		} else {
+			pci_default_pm_suspend(pci_dev);
+		}
+	} else {
+		error = pci_legacy_suspend(dev, PMSG_FREEZE);
+	}
+
+	return error;
+}
+
+static int pci_pm_freeze_noirq(struct device *dev)
+{
+	struct pci_dev *pci_dev = to_pci_dev(dev);
+	struct pci_driver *drv = pci_dev->driver;
+	int error = 0;
+
+	if (drv && drv->pm) {
+		if (drv->pm->freeze_noirq) {
+			error = drv->pm->freeze_noirq(dev);
+			suspend_report_result(drv->pm->freeze_noirq, error);
+		}
+	} else {
+		error = pci_legacy_suspend_late(dev, PMSG_FREEZE);
+	}
+
+	return error;
+}
+
+static int pci_pm_thaw(struct device *dev)
+{
+	struct pci_dev *pci_dev = to_pci_dev(dev);
+	struct device_driver *drv = dev->driver;
+	int error = 0;
+
+	if (drv && drv->pm) {
+		if (drv->pm->thaw)
+			error =  drv->pm->thaw(dev);
+	} else {
+		error = pci_legacy_resume(dev);
+	}
+
+	return error;
+}
+
+static int pci_pm_thaw_noirq(struct device *dev)
+{
+	struct pci_dev *pci_dev = to_pci_dev(dev);
+	struct pci_driver *drv = pci_dev->driver;
+	int error = 0;
+
+	if (drv && drv->pm) {
+		if (drv->pm->thaw_noirq)
+			error = drv->pm->thaw_noirq(dev);
+	} else {
+		error = pci_legacy_resume_early(dev);
+	}
+
+	return error;
+}
+
+static int pci_pm_poweroff(struct device *dev)
+{
+	struct pci_dev *pci_dev = to_pci_dev(dev);
+	struct device_driver *drv = dev->driver;
+	int error = 0;
+
+	if (drv && drv->pm) {
+		if (drv->pm->poweroff) {
+			error = drv->pm->poweroff(dev);
+			suspend_report_result(drv->pm->poweroff, error);
+		}
+	} else {
+		error = pci_legacy_suspend(dev, PMSG_HIBERNATE);
+	}
+
+	return error;
+}
+
+static int pci_pm_poweroff_noirq(struct device *dev)
+{
+	struct pci_dev *pci_dev = to_pci_dev(dev);
+	struct pci_driver *drv = pci_dev->driver;
+	int error = 0;
+
+	if (drv && drv->pm) {
+		if (drv->pm->poweroff_noirq) {
+			error = drv->pm->poweroff_noirq(dev);
+			suspend_report_result(drv->pm->poweroff_noirq, error);
+		}
+	} else {
+		error = pci_legacy_suspend_late(dev, PMSG_HIBERNATE);
+	}
+
+	return error;
+}
+
+static int pci_pm_restore(struct device *dev)
+{
+	struct pci_dev *pci_dev = to_pci_dev(dev);
+	struct device_driver *drv = dev->driver;
+	int error;
+
+	if (drv && drv->pm) {
+		error = drv->pm->restore ? drv->pm->restore(dev) :
+			pci_default_pm_resume(pci_dev);
+	} else {
+		error = pci_legacy_resume(dev);
+	}
+
+	return error;
+}
+
+static int pci_pm_restore_noirq(struct device *dev)
+{
+	struct pci_dev *pci_dev = to_pci_dev(dev);
+	struct pci_driver *drv = pci_dev->driver;
+	int error = 0;
+
+	pci_fixup_device(pci_fixup_resume, pci_dev);
+
+	if (drv && drv->pm) {
+		if (drv->pm->restore_noirq)
+			error = drv->pm->restore_noirq(dev);
+	} else {
+		error = pci_legacy_resume_early(dev);
+	}
+
+	return error;
+}
+
+#else /* !CONFIG_HIBERNATION */
+
+#define pci_pm_freeze		NULL
+#define pci_pm_freeze_noirq	NULL
+#define pci_pm_thaw		NULL
+#define pci_pm_thaw_noirq	NULL
+#define pci_pm_poweroff		NULL
+#define pci_pm_poweroff_noirq	NULL
+#define pci_pm_restore		NULL
+#define pci_pm_restore_noirq	NULL
+
+#endif /* !CONFIG_HIBERNATION */
+
+struct pm_ext_ops pci_pm_ops = {
+	.base = {
+		.prepare = pci_pm_prepare,
+		.complete = pci_pm_complete,
+		.suspend = pci_pm_suspend,
+		.resume = pci_pm_resume,
+		.freeze = pci_pm_freeze,
+		.thaw = pci_pm_thaw,
+		.poweroff = pci_pm_poweroff,
+		.restore = pci_pm_restore,
+	},
+	.suspend_noirq = pci_pm_suspend_noirq,
+	.resume_noirq = pci_pm_resume_noirq,
+	.freeze_noirq = pci_pm_freeze_noirq,
+	.thaw_noirq = pci_pm_thaw_noirq,
+	.poweroff_noirq = pci_pm_poweroff_noirq,
+	.restore_noirq = pci_pm_restore_noirq,
+};
+
+#define PCI_PM_OPS_PTR	&pci_pm_ops
+
+#else /* !CONFIG_PM_SLEEP */
+
+#define PCI_PM_OPS_PTR	NULL
+
+#endif /* !CONFIG_PM_SLEEP */
+
 /**
  * __pci_register_driver - register a new pci driver
  * @drv: the driver structure to register
@@ -381,6 +676,9 @@ int __pci_register_driver(struct pci_dri
 	drv->driver.owner = owner;
 	drv->driver.mod_name = mod_name;
 
+	if (drv->pm)
+		drv->driver.pm = &drv->pm->base;
+
 	spin_lock_init(&drv->dynids.lock);
 	INIT_LIST_HEAD(&drv->dynids.list);
 
@@ -506,12 +804,9 @@ struct bus_type pci_bus_type = {
 	.uevent		= pci_uevent,
 	.probe		= pci_device_probe,
 	.remove		= pci_device_remove,
-	.suspend	= pci_device_suspend,
-	.suspend_late	= pci_device_suspend_late,
-	.resume_early	= pci_device_resume_early,
-	.resume		= pci_device_resume,
 	.shutdown	= pci_device_shutdown,
 	.dev_attrs	= pci_dev_attrs,
+	.pm		= PCI_PM_OPS_PTR,
 };
 
 static int __init pci_driver_init(void)
Index: linux-2.6/include/linux/pci.h
===================================================================
--- linux-2.6.orig/include/linux/pci.h
+++ linux-2.6/include/linux/pci.h
@@ -381,7 +381,7 @@ struct pci_driver {
 	int  (*resume_early) (struct pci_dev *dev);
 	int  (*resume) (struct pci_dev *dev);	                /* Device woken up */
 	void (*shutdown) (struct pci_dev *dev);
-
+	struct pm_ext_ops *pm;
 	struct pci_error_handlers *err_handler;
 	struct device_driver	driver;
 	struct pci_dynids dynids;

Re: [RFC][PATCH 1/3] PM: Introduce new top level suspend and hibernation callbacks (rev. 5)

[Rafael J. Wysocki]

On Saturday, 29 of March 2008, Rafael J. Wysocki wrote:
> From: Rafael J. Wysocki <rjw@sisk.pl>
> 
> Introduce 'struct pm_ops' and 'struct pm_ext_ops' representing
> suspend and hibernation operations for bus types, device classes and
> device types.
> 
> Modify the PM core to use 'struct pm_ops' and 'struct pm_ext_ops'
> objects, if defined, instead of the ->suspend() and ->resume() or,
> respectively, ->suspend_late() and ->resume_early() callbacks that
> will be considered as legacy and gradually phased out.

Unfortunately I forgot to set dev->power.status to DPM_PREPARING before
calling ->prepare(), as documented.  Also, dpm_prepare() could cleaned up
a bit.

Fixed patch follows.

Thanks,
Rafael


---
From: Rafael J. Wysocki <rjw@sisk.pl>

Introduce 'struct pm_ops' and 'struct pm_ext_ops' representing
suspend and hibernation operations for bus types, device classes and
device types.

Modify the PM core to use 'struct pm_ops' and 'struct pm_ext_ops'
objects, if defined, instead of the ->suspend() and ->resume() or,
respectively, ->suspend_late() and ->resume_early() callbacks that
will be considered as legacy and gradually phased out.

The main purpose of doing this is to separate suspend (aka S2RAM and
standby) callbacks from hibernation callbacks in such a way that the
new callbacks won't take arguments and the semantics of each of them
will be clearly specified.  This has been requested for multiple
times by many people, including Linus himself, and the reason is that
within the current scheme if ->resume() is called, for example, it's
difficult to say why it's been called (ie. is it a resume from RAM or
from hibernation or a suspend/hibernation failure etc.?).

The second purpose is to make the suspend/hibernation callbacks more
flexible so that device drivers can handle more than they can within
the current scheme.  For example, some drivers may need to prevent
new children of the device from being registered before their
->suspend() callbacks are executed or they may want to carry out some
operations requiring the availability of some other devices, not
directly bound via the parent-child relationship, in order to prepare
for the execution of ->suspend(), etc.

Ultimately, we'd like to stop using the freezing of tasks for suspend
and therefore the drivers' suspend/hibernation code will have to take
care of the handling of the user space during suspend/hibernation.
That, in turn, would be difficult within the current scheme, without
the new ->prepare() and ->complete() callbacks.

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

 arch/x86/kernel/apm_32.c   |    4 
 drivers/base/power/main.c  |  693 ++++++++++++++++++++++++++++++++++-----------
 drivers/base/power/power.h |    2 
 drivers/base/power/trace.c |    4 
 include/linux/device.h     |    9 
 include/linux/pm.h         |  318 ++++++++++++++++++--
 kernel/power/disk.c        |   20 -
 kernel/power/main.c        |    6 
 8 files changed, 857 insertions(+), 199 deletions(-)

Index: linux-2.6/include/linux/pm.h
===================================================================
--- linux-2.6.orig/include/linux/pm.h
+++ linux-2.6/include/linux/pm.h
@@ -114,7 +114,9 @@ typedef struct pm_message {
 	int event;
 } pm_message_t;
 
-/*
+/**
+ * struct pm_ops - device PM callbacks
+ *
  * Several driver power state transitions are externally visible, affecting
  * the state of pending I/O queues and (for drivers that touch hardware)
  * interrupts, wakeups, DMA, and other hardware state.  There may also be
@@ -122,6 +124,288 @@ typedef struct pm_message {
  * to the rest of the driver stack (such as a driver that's ON gating off
  * clocks which are not in active use).
  *
+ * The externally visible transitions are handled with the help of the following
+ * callbacks included in this structure:
+ *
+ * @prepare: Prepare the device for the upcoming transition, but do NOT change
+ *	its hardware state.  Prevent new children of the device from being
+ *	registered after @prepare() returns (the driver's subsystem and
+ *	generally the rest of the kernel is supposed to prevent new calls to the
+ *	probe method from being made too once @prepare() has succeeded).  If
+ *	@prepare() detects a situation it cannot handle (e.g. registration of a
+ *	child already in progress), it may return -EAGAIN, so that the PM core
+ *	can execute it once again (e.g. after the new child has 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 @prepare() for all devices before starting to
+ *	execute suspend callbacks for any of them, so drivers may assume all of
+ *	the other devices to be present and functional while @prepare() is being
+ *	executed.  In particular, it is safe to make GFP_KERNEL memory
+ *	allocations from within @prepare(), although they are likely to fail in
+ *	case of hibernation, if a substantial amount of memory is requested.
+ *	However, drivers may NOT assume anything about the availability of the
+ *	user space at that time and it is not correct to request firmware from
+ *	within @prepare() (it's too late to do that).
+ *
+ * @complete: Undo the changes made by @prepare().  This method is executed for
+ *	all kinds of resume transitions, following one of the resume callbacks:
+ *	@resume(), @thaw(), @restore().  Also called if the state transition
+ *	fails before the driver's suspend callback (@suspend(), @freeze(),
+ *	@poweroff()) can be executed (e.g. if the suspend callback fails for one
+ *	of the other devices that the PM core has unsucessfully attempted to
+ *	suspend earlier).
+ *	The PM core executes @complete() after it has executed the appropriate
+ *	resume callback for all devices.
+ *
+ * @suspend: Executed before putting the system into a sleep state in which the
+ *	contents of main memory are preserved.  Quiesce the device, put it into
+ *	a low power state appropriate for the upcoming system state (such as
+ *	PCI_D3hot), and enable wakeup events as appropriate.
+ *
+ * @resume: Executed after waking the system up from a sleep state in which the
+ *	contents of main memory were preserved.  Put the device into the
+ *	appropriate state, according to the information saved in memory by the
+ *	preceding @suspend().  The driver starts working again, responding to
+ *	hardware events and software requests.  The hardware may have gone
+ *	through a power-off reset, or it may have maintained state from the
+ *	previous suspend() which the driver may rely on while resuming.  On most
+ *	platforms, there are no restrictions on availability of resources like
+ *	clocks during @resume().
+ *
+ * @freeze: Hibernation-specific, executed before creating a hibernation image.
+ *	Quiesce operations so that a consistent image can be created, but do NOT
+ *	otherwise put the device into a low power device state and do NOT emit
+ *	system wakeup events.  Save in main memory the device settings to be
+ *	used by @restore() during the subsequent resume from hibernation or by
+ *	the subsequent @thaw(), if the creation of the image or the restoration
+ *	of main memory contents from it fails.
+ *
+ * @thaw: Hibernation-specific, executed after creating a hibernation image OR
+ *	if the creation of the image fails.  Also executed after a failing
+ *	attempt to restore the contents of main memory from such an image.
+ *	Undo the changes made by the preceding @freeze(), so the device can be
+ *	operated in the same way as immediately before the call to @freeze().
+ *
+ * @poweroff: Hibernation-specific, executed after saving a hibernation image.
+ *	Quiesce the device, put it into a low power state appropriate for the
+ *	upcoming system state (such as PCI_D3hot), and enable wakeup events as
+ *	appropriate.
+ *
+ * @restore: Hibernation-specific, executed after restoring the contents of main
+ *	memory from a hibernation image.  Driver starts working again,
+ *	responding to hardware events and software requests.  Drivers may NOT
+ *	make ANY assumptions about the hardware state right prior to @restore().
+ *	On most platforms, there are no restrictions on availability of
+ *	resources like clocks during @restore().
+ *
+ * All of the above callbacks, except for @complete(), return error codes.
+ * However, the error codes returned by the resume operations, @resume(),
+ * @thaw(), and @restore(), do not cause the PM core to abort the resume
+ * transition during which they are returned.  Instead, the PM core marks
+ * the devices for which they are returned and all of their children as
+ * "invalid" and doesn't attempt to execute any other suspend/hibernation
+ * callbacks for them (including @complete()).  If a device marked as "invalid"
+ * is encountered during the preparation phase (i.e. when devices' @prepare()
+ * methods are executed), the transition will be aborted and -EINVAL will be
+ * returned. [The only way to recover from this situation is to unregister the
+ * "invalid" device(s).]
+ *
+ * It is allowed to unregister devices while the above callbacks are being
+ * executed.  However, it is not allowed to unregister a device from within any
+ * of its own callbacks.
+ */
+
+struct pm_ops {
+	int (*prepare)(struct device *dev);
+	void (*complete)(struct device *dev);
+	int (*suspend)(struct device *dev);
+	int (*resume)(struct device *dev);
+	int (*freeze)(struct device *dev);
+	int (*thaw)(struct device *dev);
+	int (*poweroff)(struct device *dev);
+	int (*restore)(struct device *dev);
+};
+
+/**
+ * struct pm_ext_ops - extended device PM callbacks
+ *
+ * Some devices require certain operations related to suspend and hibernation
+ * to be carried out with interrupts disabled.  Thus, 'struct pm_ext_ops' below
+ * is defined, adding callbacks to be executed with interrupts disabled to
+ * 'struct pm_ops'.
+ *
+ * The following callbacks included in 'struct pm_ext_ops' are executed with
+ * the nonboot CPUs switched off and with interrupts disabled on the only
+ * functional CPU.  They also are executed with the PM core list of devices
+ * locked, so they must NOT unregister any devices.
+ *
+ * @suspend_noirq: Complete the operations of ->suspend() by carrying out any
+ *	actions required for suspending the device that need interrupts to be
+ *	disabled
+ *
+ * @resume_noirq: Prepare for the execution of ->resume() by carrying out any
+ *	actions required for resuming the device that need interrupts to be
+ *	disabled
+ *
+ * @freeze_noirq: Complete the operations of ->freeze() by carrying out any
+ *	actions required for freezing the device that need interrupts to be
+ *	disabled
+ *
+ * @thaw_noirq: Prepare for the execution of ->thaw() by carrying out any
+ *	actions required for thawing the device that need interrupts to be
+ *	disabled
+ *
+ * @poweroff_noirq: Complete the operations of ->poweroff() by carrying out any
+ *	actions required for handling the device that need interrupts to be
+ *	disabled
+ *
+ * @restore_noirq: Prepare for the execution of ->restore() by carrying out any
+ *	actions required for restoring the operations of the device that need
+ *	interrupts to be disabled
+ *
+ * All of the above callbacks return error codes, but the error codes returned
+ * by the resume operations, @resume_noirq(), @thaw_noirq(), and
+ * @restore_noirq(), do not cause the PM core to abort the resume transition
+ * during which they are returned.  Instead, the PM core marks the devices for
+ * which they are returned and all of their children as "invalid" and doesn't
+ * attempt to execute any resume callbacks for them (including ->complete()).
+ */
+
+struct pm_ext_ops {
+	struct pm_ops base;
+	int (*suspend_noirq)(struct device *dev);
+	int (*resume_noirq)(struct device *dev);
+	int (*freeze_noirq)(struct device *dev);
+	int (*thaw_noirq)(struct device *dev);
+	int (*poweroff_noirq)(struct device *dev);
+	int (*restore_noirq)(struct device *dev);
+};
+
+/**
+ * PM_EVENT_ messages
+ *
+ * The following PM_EVENT_ messages are defined for the internal use of the PM
+ * core, in order to provide a mechanism allowing the high level suspend and
+ * hibernation code to convey the necessary information to the device PM core
+ * code:
+ *
+ * ON		No transition.
+ *
+ * FREEZE 	System is going to hibernate, call ->prepare() and ->freeze()
+ *		for all devices.
+ *
+ * SUSPEND	System is going to suspend, call ->prepare() and ->suspend()
+ *		for all devices.
+ *
+ * HIBERNATE	Hibernation image has been saved, call ->prepare() and
+ *		->poweroff() for all devices.
+ *
+ * QUIESCE	Contents of main memory are going to be restored from a (loaded)
+ *		hibernation image, call ->prepare() and ->freeze() for all
+ *		devices.
+ *
+ * RESUME	System is resuming, call ->resume() and ->complete() for all
+ *		devices.
+ *
+ * THAW		Hibernation image has been created, call ->thaw() and
+ *		->complete() for all devices.
+ *
+ * RESTORE	Contents of main memory have been restored from a hibernation
+ *		image, call ->restore() and ->complete() for all devices.
+ *
+ * RECOVER	Creation of a hibernation image or restoration of the main
+ *		memory contents from a hibernation image has failed, call
+ *		->thaw() and ->complete() for all devices.
+ */
+
+#define PM_EVENT_ON		0x0000
+#define PM_EVENT_FREEZE 	0x0001
+#define PM_EVENT_SUSPEND	0x0002
+#define PM_EVENT_HIBERNATE	0x0004
+#define PM_EVENT_QUIESCE	0x0008
+#define PM_EVENT_RESUME		0x0010
+#define PM_EVENT_THAW		0x0020
+#define PM_EVENT_RESTORE	0x0040
+#define PM_EVENT_RECOVER	0x0080
+
+#define PM_EVENT_SLEEP	(PM_EVENT_SUSPEND | PM_EVENT_HIBERNATE)
+
+#define PMSG_FREEZE	((struct pm_message){ .event = PM_EVENT_FREEZE, })
+#define PMSG_QUIESCE	((struct pm_message){ .event = PM_EVENT_QUIESCE, })
+#define PMSG_SUSPEND	((struct pm_message){ .event = PM_EVENT_SUSPEND, })
+#define PMSG_HIBERNATE	((struct pm_message){ .event = PM_EVENT_HIBERNATE, })
+#define PMSG_RESUME	((struct pm_message){ .event = PM_EVENT_RESUME, })
+#define PMSG_THAW	((struct pm_message){ .event = PM_EVENT_THAW, })
+#define PMSG_RESTORE	((struct pm_message){ .event = PM_EVENT_RESTORE, })
+#define PMSG_RECOVER	((struct pm_message){ .event = PM_EVENT_RECOVER, })
+#define PMSG_ON		((struct pm_message){ .event = PM_EVENT_ON, })
+
+/**
+ * Device power management states
+ *
+ * These state labels are used internally by the PM core to indicate the current
+ * status of a device with respect to the PM core operations.
+ *
+ * DPM_INVALID		Device is not in a consistent state.  Set when one of
+ *			the device's resume callbacks, ->resume(), ->thaw(),
+ *			->restore(), ->resume()_noirq, ->thaw_noirq(), or
+ *			->restore_noirq(), fails.  Also set when the device
+ *			parent's status turns out to be DPM_INVALID.
+ *
+ * DPM_ON		Device is regarded as operational.  Set this way
+ *			initially and when ->complete() is about to be called.
+ *			Also set when ->prepare() fails.
+ *
+ * DPM_PREPARING	Device is going to be prepared for a PM transition.  Set
+ *			when ->prepare() is about to be called.
+ *
+ * DPM_RESUMING		Device is going to be resumed.  Set when ->resume(),
+ *			->thaw(), or ->restore() is about to be called.
+ *
+ * DPM_SUSPENDING	Device has been prepared for a power transition.  Set
+ *			when ->prepare() has just succeeded.
+ *
+ * DPM_OFF		Device is regarded as inactive.  Set immediately after
+ *			->suspend(), ->freeze(), or ->poweroff() has succeeded.
+ *			Also set when ->resume()_noirq, ->thaw_noirq(), or
+ *			->restore_noirq() is about to be called.
+ *
+ * DPM_OFF_IRQ		Device is in a "deep sleep".  Set immediately after
+ *			->suspend_noirq(), ->freeze_noirq(), or
+ *			->poweroff_noirq() has just succeeded.
+ */
+
+enum dpm_state {
+	DPM_INVALID,
+	DPM_ON,
+	DPM_PREPARING,
+	DPM_RESUMING,
+	DPM_SUSPENDING,
+	DPM_OFF,
+	DPM_OFF_IRQ,
+};
+
+struct dev_pm_info {
+	pm_message_t		power_state;
+	unsigned		can_wakeup:1;
+	unsigned		should_wakeup:1;
+	enum dpm_state		status;		/* Owned by the PM core */
+#ifdef	CONFIG_PM_SLEEP
+	struct list_head	entry;
+#endif
+};
+
+/*
+ * The PM_EVENT_ messages are also used by drivers implementing the legacy
+ * suspend framework, based on the ->suspend() and ->resume() callbacks common
+ * for suspend and hibernation transitions, according to the rules below.
+ */
+
+/* Necessary, because several drivers use PM_EVENT_PRETHAW */
+#define PM_EVENT_PRETHAW PM_EVENT_QUIESCE
+
+/*
  * One transition is triggered by resume(), after a suspend() call; the
  * message is implicit:
  *
@@ -166,35 +450,13 @@ typedef struct pm_message {
  * or from system low-power states such as standby or suspend-to-RAM.
  */
 
-#define PM_EVENT_ON 0
-#define PM_EVENT_FREEZE 1
-#define PM_EVENT_SUSPEND 2
-#define PM_EVENT_HIBERNATE 4
-#define PM_EVENT_PRETHAW 8
-
-#define PM_EVENT_SLEEP	(PM_EVENT_SUSPEND | PM_EVENT_HIBERNATE)
-
-#define PMSG_FREEZE	((struct pm_message){ .event = PM_EVENT_FREEZE, })
-#define PMSG_PRETHAW	((struct pm_message){ .event = PM_EVENT_PRETHAW, })
-#define PMSG_SUSPEND	((struct pm_message){ .event = PM_EVENT_SUSPEND, })
-#define PMSG_HIBERNATE	((struct pm_message){ .event = PM_EVENT_HIBERNATE, })
-#define PMSG_ON		((struct pm_message){ .event = PM_EVENT_ON, })
-
-struct dev_pm_info {
-	pm_message_t		power_state;
-	unsigned		can_wakeup:1;
-	unsigned		should_wakeup:1;
-	bool			sleeping:1;	/* Owned by the PM core */
-#ifdef	CONFIG_PM_SLEEP
-	struct list_head	entry;
-#endif
-};
+#ifdef CONFIG_PM_SLEEP
+extern void device_pm_lock(void);
+extern void device_power_up(pm_message_t state);
+extern void device_resume(pm_message_t state);
 
+extern void device_pm_unlock(void);
 extern int device_power_down(pm_message_t state);
-extern void device_power_up(void);
-extern void device_resume(void);
-
-#ifdef CONFIG_PM_SLEEP
 extern int device_suspend(pm_message_t state);
 extern int device_prepare_suspend(pm_message_t state);
 
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
@@ -12,11 +12,9 @@
  * and add it to the list of power-controlled devices. sysfs entries for
  * controlling device power management will also be added.
  *
- * A different set of lists than the global subsystem list are used to
- * keep track of power info because we use different lists to hold
- * devices based on what stage of the power management process they
- * are in. The power domain dependencies may also differ from the
- * ancestral dependencies that the subsystem list maintains.
+ * A separate list is used for keeping track of power info, because the power
+ * domain dependencies may differ from the ancestral dependencies that the
+ * subsystem list maintains.
  */
 
 #include <linux/device.h>
@@ -30,31 +28,40 @@
 #include "power.h"
 
 /*
- * The entries in the dpm_active list are in a depth first order, simply
+ * The entries in the dpm_list list are in a depth first order, simply
  * because children are guaranteed to be discovered after parents, and
  * are inserted at the back of the list on discovery.
  *
- * All the other lists are kept in the same order, for consistency.
- * However the lists aren't always traversed in the same order.
- * Semaphores must be acquired from the top (i.e., front) down
- * and released in the opposite order.  Devices must be suspended
- * from the bottom (i.e., end) up and resumed in the opposite order.
- * That way no parent will be suspended while it still has an active
- * child.
- *
  * Since device_pm_add() may be called with a device semaphore held,
  * we must never try to acquire a device semaphore while holding
  * dpm_list_mutex.
  */
 
-LIST_HEAD(dpm_active);
-static LIST_HEAD(dpm_off);
-static LIST_HEAD(dpm_off_irq);
+LIST_HEAD(dpm_list);
 
 static DEFINE_MUTEX(dpm_list_mtx);
 
-/* 'true' if all devices have been suspended, protected by dpm_list_mtx */
-static bool all_sleeping;
+/*
+ * Set once the preparation of devices for a PM transition has started, reset
+ * before starting to resume devices.  Protected by dpm_list_mtx.
+ */
+static bool transition_started;
+
+/**
+ *	device_pm_lock - lock the list of active devices used by the PM core
+ */
+void device_pm_lock(void)
+{
+	mutex_lock(&dpm_list_mtx);
+}
+
+/**
+ *	device_pm_unlock - unlock the list of active devices used by the PM core
+ */
+void device_pm_unlock(void)
+{
+	mutex_unlock(&dpm_list_mtx);
+}
 
 /**
  *	device_pm_add - add a device to the list of active devices
@@ -68,22 +75,36 @@ int device_pm_add(struct device *dev)
 		 dev->bus ? dev->bus->name : "No Bus",
 		 kobject_name(&dev->kobj));
 	mutex_lock(&dpm_list_mtx);
-	if ((dev->parent && dev->parent->power.sleeping) || all_sleeping) {
-		if (dev->parent->power.sleeping)
-			dev_warn(dev,
-				"parent %s is sleeping, will not add\n",
+	if (dev->parent) {
+		if (dev->parent->power.status == DPM_INVALID) {
+			dev_warn(dev, "state of the parent %s is inconsistent, "
+				"will not add\n", dev->parent->bus_id);
+			goto Refuse;
+		} else if (dev->parent->power.status >= DPM_SUSPENDING) {
+			dev_warn(dev, "parent %s is sleeping, will not add\n",
 				dev->parent->bus_id);
-		else
-			dev_warn(dev, "devices are sleeping, will not add\n");
-		WARN_ON(true);
-		error = -EBUSY;
-	} else {
-		error = dpm_sysfs_add(dev);
-		if (!error)
-			list_add_tail(&dev->power.entry, &dpm_active);
+			goto Refuse;
+		}
+	} else if (transition_started) {
+		/*
+		 * We refuse to register parentless devices while a PM
+		 * transition is in progress in order to avoid leaving them
+		 * unhandled down the road
+		 */
+		goto Refuse;
+	}
+	error = dpm_sysfs_add(dev);
+	if (!error) {
+		dev->power.status = DPM_ON;
+		list_add_tail(&dev->power.entry, &dpm_list);
 	}
+ End:
 	mutex_unlock(&dpm_list_mtx);
 	return error;
+ Refuse:
+	WARN_ON(true);
+	error = -EBUSY;
+	goto End;
 }
 
 /**
@@ -99,77 +120,242 @@ void device_pm_remove(struct device *dev
 		 kobject_name(&dev->kobj));
 	mutex_lock(&dpm_list_mtx);
 	dpm_sysfs_remove(dev);
+	dev->power.status = DPM_INVALID;
 	list_del_init(&dev->power.entry);
 	mutex_unlock(&dpm_list_mtx);
 }
 
+/**
+ *	pm_op - execute the PM operation appropiate for given PM event
+ *	@dev:	Device.
+ *	@ops:	PM operations to choose from.
+ *	@state:	PM transition of the system being carried out.
+ */
+static int pm_op(struct device *dev, struct pm_ops *ops, pm_message_t state)
+{
+	int error = 0;
+
+	switch (state.event) {
+#ifdef CONFIG_SUSPEND
+	case PM_EVENT_SUSPEND:
+		if (ops->suspend) {
+			error = ops->suspend(dev);
+			suspend_report_result(ops->suspend, error);
+		}
+		break;
+	case PM_EVENT_RESUME:
+		if (ops->resume) {
+			error = ops->resume(dev);
+			suspend_report_result(ops->resume, error);
+		}
+		break;
+#endif /* CONFIG_SUSPEND */
+#ifdef CONFIG_HIBERNATION
+	case PM_EVENT_FREEZE:
+	case PM_EVENT_QUIESCE:
+		if (ops->freeze) {
+			error = ops->freeze(dev);
+			suspend_report_result(ops->freeze, error);
+		}
+		break;
+	case PM_EVENT_HIBERNATE:
+		if (ops->poweroff) {
+			error = ops->poweroff(dev);
+			suspend_report_result(ops->poweroff, error);
+		}
+		break;
+	case PM_EVENT_THAW:
+	case PM_EVENT_RECOVER:
+		if (ops->thaw) {
+			error = ops->thaw(dev);
+			suspend_report_result(ops->thaw, error);
+		}
+		break;
+	case PM_EVENT_RESTORE:
+		if (ops->restore) {
+			error = ops->restore(dev);
+			suspend_report_result(ops->restore, error);
+		}
+		break;
+#endif /* CONFIG_HIBERNATION */
+	default:
+		error = -EINVAL;
+	}
+	return error;
+}
+
+/**
+ *	pm_noirq_op - execute the PM operation appropiate for given PM event
+ *	@dev:	Device.
+ *	@ops:	PM operations to choose from.
+ *	@state: PM transition of the system being carried out.
+ *
+ *	The operation is executed with interrupts disabled by the only remaining
+ *	functional CPU in the system.
+ */
+static int pm_noirq_op(struct device *dev, struct pm_ext_ops *ops,
+			pm_message_t state)
+{
+	int error = 0;
+
+	switch (state.event) {
+#ifdef CONFIG_SUSPEND
+	case PM_EVENT_SUSPEND:
+		if (ops->suspend_noirq) {
+			error = ops->suspend_noirq(dev);
+			suspend_report_result(ops->suspend_noirq, error);
+		}
+		break;
+	case PM_EVENT_RESUME:
+		if (ops->resume_noirq) {
+			error = ops->resume_noirq(dev);
+			suspend_report_result(ops->resume_noirq, error);
+		}
+		break;
+#endif /* CONFIG_SUSPEND */
+#ifdef CONFIG_HIBERNATION
+	case PM_EVENT_FREEZE:
+	case PM_EVENT_QUIESCE:
+		if (ops->freeze_noirq) {
+			error = ops->freeze_noirq(dev);
+			suspend_report_result(ops->freeze_noirq, error);
+		}
+		break;
+	case PM_EVENT_HIBERNATE:
+		if (ops->poweroff_noirq) {
+			error = ops->poweroff_noirq(dev);
+			suspend_report_result(ops->poweroff_noirq, error);
+		}
+		break;
+	case PM_EVENT_THAW:
+	case PM_EVENT_RECOVER:
+		if (ops->thaw_noirq) {
+			error = ops->thaw_noirq(dev);
+			suspend_report_result(ops->thaw_noirq, error);
+		}
+		break;
+	case PM_EVENT_RESTORE:
+		if (ops->restore_noirq) {
+			error = ops->restore_noirq(dev);
+			suspend_report_result(ops->restore_noirq, error);
+		}
+		break;
+#endif /* CONFIG_HIBERNATION */
+	default:
+		error = -EINVAL;
+	}
+	return error;
+}
+
+static char *pm_verb(int event)
+{
+	switch (event) {
+	case PM_EVENT_SUSPEND:
+		return "suspend";
+	case PM_EVENT_RESUME:
+		return "resume";
+	case PM_EVENT_FREEZE:
+		return "freeze";
+	case PM_EVENT_QUIESCE:
+		return "quiesce";
+	case PM_EVENT_HIBERNATE:
+		return "hibernate";
+	case PM_EVENT_THAW:
+		return "thaw";
+	case PM_EVENT_RESTORE:
+		return "restore";
+	default:
+		return "(unknown PM event)";
+	}
+}
+
+static void pm_dev_dbg(struct device *dev, pm_message_t state, char *info)
+{
+	dev_dbg(dev, "%s%s%s\n", info, pm_verb(state.event),
+		((state.event & PM_EVENT_SLEEP) && device_may_wakeup(dev)) ?
+		", may wakeup" : "");
+}
+
 /*------------------------- Resume routines -------------------------*/
 
 /**
- *	resume_device_early - Power on one device (early resume).
+ *	resume_device_noirq - Power on one device (early resume).
  *	@dev:	Device.
+ *	@state: PM transition of the system being carried out.
  *
  *	Must be called with interrupts disabled.
  */
-static int resume_device_early(struct device *dev)
+static int resume_device_noirq(struct device *dev, pm_message_t state)
 {
 	int error = 0;
 
 	TRACE_DEVICE(dev);
 	TRACE_RESUME(0);
 
-	if (dev->bus && dev->bus->resume_early) {
-		dev_dbg(dev, "EARLY resume\n");
+	if (!dev->bus)
+		goto End;
+
+	if (dev->bus->pm) {
+		pm_dev_dbg(dev, state, "EARLY ");
+		error = pm_noirq_op(dev, dev->bus->pm, state);
+	} else if (dev->bus->resume_early) {
+		pm_dev_dbg(dev, state, "legacy EARLY ");
 		error = dev->bus->resume_early(dev);
 	}
-
+ End:
 	TRACE_RESUME(error);
 	return error;
 }
 
 /**
  *	dpm_power_up - Power on all regular (non-sysdev) devices.
+ *	@state: PM transition of the system being carried out.
  *
- *	Walk the dpm_off_irq list and power each device up. This
- *	is used for devices that required they be powered down with
- *	interrupts disabled. As devices are powered on, they are moved
- *	to the dpm_off list.
+ *	Execute the appropriate "noirq resume" callback for all devices marked
+ *	as DPM_OFF_IRQ.
  *
  *	Must be called with interrupts disabled and only one CPU running.
  */
-static void dpm_power_up(void)
+static void dpm_power_up(pm_message_t state)
 {
+	struct device *dev;
 
-	while (!list_empty(&dpm_off_irq)) {
-		struct list_head *entry = dpm_off_irq.next;
-		struct device *dev = to_device(entry);
-
-		list_move_tail(entry, &dpm_off);
-		resume_device_early(dev);
+	list_for_each_entry(dev, &dpm_list, power.entry) {
+		if (dev->parent && dev->parent->power.status == DPM_INVALID) {
+			dev->power.status = DPM_INVALID;
+		} else if (dev->power.status > DPM_OFF) {
+			int error;
+
+			dev->power.status = DPM_OFF;
+			error = resume_device_noirq(dev, state);
+			if (error)
+				dev->power.status = DPM_INVALID;
+		}
 	}
 }
 
 /**
  *	device_power_up - Turn on all devices that need special attention.
+ *	@state: PM transition of the system being carried out.
  *
  *	Power on system devices, then devices that required we shut them down
  *	with interrupts disabled.
  *
  *	Must be called with interrupts disabled.
  */
-void device_power_up(void)
+void device_power_up(pm_message_t state)
 {
 	sysdev_resume();
-	dpm_power_up();
+	dpm_power_up(state);
 }
 EXPORT_SYMBOL_GPL(device_power_up);
 
 /**
  *	resume_device - Restore state for one device.
  *	@dev:	Device.
- *
+ *	@state: PM transition of the system being carried out.
  */
-static int resume_device(struct device *dev)
+static int resume_device(struct device *dev, pm_message_t state)
 {
 	int error = 0;
 
@@ -178,21 +364,40 @@ static int resume_device(struct device *
 
 	down(&dev->sem);
 
-	if (dev->bus && dev->bus->resume) {
-		dev_dbg(dev,"resuming\n");
-		error = dev->bus->resume(dev);
+	if (dev->bus) {
+		if (dev->bus->pm) {
+			pm_dev_dbg(dev, state, "");
+			error = pm_op(dev, &dev->bus->pm->base, state);
+		} else if (dev->bus->resume) {
+			pm_dev_dbg(dev, state, "legacy ");
+			error = dev->bus->resume(dev);
+		}
+		if (error)
+			goto End;
 	}
 
-	if (!error && dev->type && dev->type->resume) {
-		dev_dbg(dev,"resuming\n");
-		error = dev->type->resume(dev);
+	if (dev->type) {
+		if (dev->type->pm) {
+			pm_dev_dbg(dev, state, "type ");
+			error = pm_op(dev, dev->type->pm, state);
+		} else if (dev->type->resume) {
+			pm_dev_dbg(dev, state, "legacy type ");
+			error = dev->type->resume(dev);
+		}
+		if (error)
+			goto End;
 	}
 
-	if (!error && dev->class && dev->class->resume) {
-		dev_dbg(dev,"class resume\n");
-		error = dev->class->resume(dev);
+	if (dev->class) {
+		if (dev->class->pm) {
+			pm_dev_dbg(dev, state, "class ");
+			error = pm_op(dev, dev->class->pm, state);
+		} else if (dev->class->resume) {
+			pm_dev_dbg(dev, state, "legacy class ");
+			error = dev->class->resume(dev);
+		}
 	}
-
+ End:
 	up(&dev->sem);
 
 	TRACE_RESUME(error);
@@ -201,78 +406,163 @@ static int resume_device(struct device *
 
 /**
  *	dpm_resume - Resume every device.
+ *	@state: PM transition of the system being carried out.
  *
- *	Resume the devices that have either not gone through
- *	the late suspend, or that did go through it but also
- *	went through the early resume.
+ *	Execute the appropriate "resume" callback for all devices the status of
+ *	which indicates that they are inactive.
+ */
+static void dpm_resume(pm_message_t state)
+{
+	struct list_head list;
+
+	INIT_LIST_HEAD(&list);
+	mutex_lock(&dpm_list_mtx);
+	transition_started = false;
+	while (!list_empty(&dpm_list)) {
+		struct device *dev = to_device(dpm_list.next);
+
+		get_device(dev);
+		if (dev->parent && dev->parent->power.status == DPM_INVALID) {
+			dev->power.status = DPM_INVALID;
+		} else if (dev->power.status >= DPM_OFF) {
+			int error;
+
+			dev->power.status = DPM_RESUMING;
+			mutex_unlock(&dpm_list_mtx);
+
+			error = resume_device(dev, state);
+
+			mutex_lock(&dpm_list_mtx);
+			if (error)
+				dev->power.status = DPM_INVALID;
+		} else if (dev->power.status == DPM_SUSPENDING) {
+			/* Allow new children of the device to be registered */
+			dev->power.status = DPM_RESUMING;
+		}
+		if (!list_empty(&dev->power.entry))
+			list_move_tail(&dev->power.entry, &list);
+		put_device(dev);
+	}
+	list_splice(&list, &dpm_list);
+	mutex_unlock(&dpm_list_mtx);
+}
+
+/**
+ *	complete_device - Complete a PM transition for given device
+ *	@dev:	Device.
+ *	@state: PM transition of the system being carried out.
+ */
+static void complete_device(struct device *dev, pm_message_t state)
+{
+	down(&dev->sem);
+
+	if (dev->class && dev->class->pm && dev->class->pm->complete) {
+		pm_dev_dbg(dev, state, "completing class ");
+		dev->class->pm->complete(dev);
+	}
+
+	if (dev->type && dev->type->pm && dev->type->pm->complete) {
+		pm_dev_dbg(dev, state, "completing type ");
+		dev->type->pm->complete(dev);
+	}
+
+	if (dev->bus && dev->bus->pm && dev->bus->pm->base.complete) {
+		pm_dev_dbg(dev, state, "completing ");
+		dev->bus->pm->base.complete(dev);
+	}
+
+	up(&dev->sem);
+}
+
+/**
+ *	dpm_complete - Complete a PM transition for all devices.
+ *	@state: PM transition of the system being carried out.
  *
- *	Take devices from the dpm_off_list, resume them,
- *	and put them on the dpm_locked list.
+ *	Execute the ->complete() callbacks for all devices that are not marked
+ *	as DPM_ON.
  */
-static void dpm_resume(void)
+static void dpm_complete(pm_message_t state)
 {
+	struct list_head list;
+
+	INIT_LIST_HEAD(&list);
 	mutex_lock(&dpm_list_mtx);
-	all_sleeping = false;
-	while(!list_empty(&dpm_off)) {
-		struct list_head *entry = dpm_off.next;
-		struct device *dev = to_device(entry);
+	while (!list_empty(&dpm_list)) {
+		struct device *dev = to_device(dpm_list.prev);
 
-		list_move_tail(entry, &dpm_active);
-		dev->power.sleeping = false;
-		mutex_unlock(&dpm_list_mtx);
-		resume_device(dev);
-		mutex_lock(&dpm_list_mtx);
+		get_device(dev);
+		if (dev->power.status > DPM_ON) {
+			dev->power.status = DPM_ON;
+			mutex_unlock(&dpm_list_mtx);
+
+			complete_device(dev, state);
+
+			mutex_lock(&dpm_list_mtx);
+		}
+		if (!list_empty(&dev->power.entry))
+			list_move(&dev->power.entry, &list);
+		put_device(dev);
 	}
+	list_splice(&list, &dpm_list);
 	mutex_unlock(&dpm_list_mtx);
 }
 
 /**
  *	device_resume - Restore state of each device in system.
+ *	@state: PM transition of the system being carried out.
  *
  *	Resume all the devices, unlock them all, and allow new
  *	devices to be registered once again.
  */
-void device_resume(void)
+void device_resume(pm_message_t state)
 {
 	might_sleep();
-	dpm_resume();
+	dpm_resume(state);
+	dpm_complete(state);
 }
 EXPORT_SYMBOL_GPL(device_resume);
 
 
 /*------------------------- Suspend routines -------------------------*/
 
-static inline char *suspend_verb(u32 event)
+/**
+ *	resume_event - return a PM message representing the resume event
+ *	               corresponding to given sleep state.
+ *	@sleep_state: PM message representing a sleep state.
+ */
+static pm_message_t resume_event(pm_message_t sleep_state)
 {
-	switch (event) {
-	case PM_EVENT_SUSPEND:	return "suspend";
-	case PM_EVENT_FREEZE:	return "freeze";
-	case PM_EVENT_PRETHAW:	return "prethaw";
-	default:		return "(unknown suspend event)";
+	switch (sleep_state.event) {
+	case PM_EVENT_SUSPEND:
+		return PMSG_RESUME;
+	case PM_EVENT_FREEZE:
+	case PM_EVENT_QUIESCE:
+		return PMSG_RECOVER;
+	case PM_EVENT_HIBERNATE:
+		return PMSG_RESTORE;
 	}
-}
-
-static void
-suspend_device_dbg(struct device *dev, pm_message_t state, char *info)
-{
-	dev_dbg(dev, "%s%s%s\n", info, suspend_verb(state.event),
-		((state.event == PM_EVENT_SUSPEND) && device_may_wakeup(dev)) ?
-		", may wakeup" : "");
+	return PMSG_ON;
 }
 
 /**
- *	suspend_device_late - Shut down one device (late suspend).
+ *	suspend_device_noirq - Shut down one device (late suspend).
  *	@dev:	Device.
- *	@state:	Power state device is entering.
+ *	@state: PM transition of the system being carried out.
  *
  *	This is called with interrupts off and only a single CPU running.
  */
-static int suspend_device_late(struct device *dev, pm_message_t state)
+static int suspend_device_noirq(struct device *dev, pm_message_t state)
 {
 	int error = 0;
 
-	if (dev->bus && dev->bus->suspend_late) {
-		suspend_device_dbg(dev, state, "LATE ");
+	if (!dev->bus)
+		return 0;
+
+	if (dev->bus->pm) {
+		pm_dev_dbg(dev, state, "LATE ");
+		error = pm_noirq_op(dev, dev->bus->pm, state);
+	} else if (dev->bus->suspend_late) {
+		pm_dev_dbg(dev, state, "legacy LATE ");
 		error = dev->bus->suspend_late(dev, state);
 		suspend_report_result(dev->bus->suspend_late, error);
 	}
@@ -281,37 +571,32 @@ static int suspend_device_late(struct de
 
 /**
  *	device_power_down - Shut down special devices.
- *	@state:		Power state to enter.
+ *	@state: PM transition of the system being carried out.
  *
- *	Power down devices that require interrupts to be disabled
- *	and move them from the dpm_off list to the dpm_off_irq list.
+ *	Power down devices that require interrupts to be disabled.
  *	Then power down system devices.
  *
  *	Must be called with interrupts disabled and only one CPU running.
  */
 int device_power_down(pm_message_t state)
 {
+	struct device *dev;
 	int error = 0;
 
-	while (!list_empty(&dpm_off)) {
-		struct list_head *entry = dpm_off.prev;
-		struct device *dev = to_device(entry);
-
-		error = suspend_device_late(dev, state);
+	list_for_each_entry_reverse(dev, &dpm_list, power.entry) {
+		error = suspend_device_noirq(dev, state);
 		if (error) {
 			printk(KERN_ERR "Could not power down device %s: "
 					"error %d\n",
 					kobject_name(&dev->kobj), error);
 			break;
 		}
-		if (!list_empty(&dev->power.entry))
-			list_move(&dev->power.entry, &dpm_off_irq);
+		dev->power.status = DPM_OFF_IRQ;
 	}
-
 	if (!error)
 		error = sysdev_suspend(state);
 	if (error)
-		dpm_power_up();
+		dpm_power_up(resume_event(state));
 	return error;
 }
 EXPORT_SYMBOL_GPL(device_power_down);
@@ -319,7 +604,7 @@ EXPORT_SYMBOL_GPL(device_power_down);
 /**
  *	suspend_device - Save state of one device.
  *	@dev:	Device.
- *	@state:	Power state device is entering.
+ *	@state: PM transition of the system being carried out.
  */
 static int suspend_device(struct device *dev, pm_message_t state)
 {
@@ -327,29 +612,43 @@ static int suspend_device(struct device 
 
 	down(&dev->sem);
 
-	if (dev->power.power_state.event) {
-		dev_dbg(dev, "PM: suspend %d-->%d\n",
-			dev->power.power_state.event, state.event);
-	}
-
-	if (dev->class && dev->class->suspend) {
-		suspend_device_dbg(dev, state, "class ");
-		error = dev->class->suspend(dev, state);
-		suspend_report_result(dev->class->suspend, error);
+	if (dev->class) {
+		if (dev->class->pm) {
+			pm_dev_dbg(dev, state, "class ");
+			error = pm_op(dev, dev->class->pm, state);
+		} else if (dev->class->suspend) {
+			pm_dev_dbg(dev, state, "legacy class ");
+			error = dev->class->suspend(dev, state);
+			suspend_report_result(dev->class->suspend, error);
+		}
+		if (error)
+			goto End;
 	}
 
-	if (!error && dev->type && dev->type->suspend) {
-		suspend_device_dbg(dev, state, "type ");
-		error = dev->type->suspend(dev, state);
-		suspend_report_result(dev->type->suspend, error);
+	if (dev->type) {
+		if (dev->type->pm) {
+			pm_dev_dbg(dev, state, "type ");
+			error = pm_op(dev, dev->type->pm, state);
+		} else if (dev->type->suspend) {
+			pm_dev_dbg(dev, state, "legacy type ");
+			error = dev->type->suspend(dev, state);
+			suspend_report_result(dev->type->suspend, error);
+		}
+		if (error)
+			goto End;
 	}
 
-	if (!error && dev->bus && dev->bus->suspend) {
-		suspend_device_dbg(dev, state, "");
-		error = dev->bus->suspend(dev, state);
-		suspend_report_result(dev->bus->suspend, error);
+	if (dev->bus) {
+		if (dev->bus->pm) {
+			pm_dev_dbg(dev, state, "");
+			error = pm_op(dev, &dev->bus->pm->base, state);
+		} else if (dev->bus->suspend) {
+			pm_dev_dbg(dev, state, "legacy ");
+			error = dev->bus->suspend(dev, state);
+			suspend_report_result(dev->bus->suspend, error);
+		}
 	}
-
+ End:
 	up(&dev->sem);
 
 	return error;
@@ -357,67 +656,147 @@ static int suspend_device(struct device 
 
 /**
  *	dpm_suspend - Suspend every device.
- *	@state:	Power state to put each device in.
- *
- *	Walk the dpm_locked list.  Suspend each device and move it
- *	to the dpm_off list.
+ *	@state: PM transition of the system being carried out.
  *
- *	(For historical reasons, if it returns -EAGAIN, that used to mean
- *	that the device would be called again with interrupts disabled.
- *	These days, we use the "suspend_late()" callback for that, so we
- *	print a warning and consider it an error).
+ *	Execute the appropriate "suspend" callbacks for all devices.
  */
 static int dpm_suspend(pm_message_t state)
 {
+	struct list_head list;
 	int error = 0;
 
+	INIT_LIST_HEAD(&list);
 	mutex_lock(&dpm_list_mtx);
-	while (!list_empty(&dpm_active)) {
-		struct list_head *entry = dpm_active.prev;
-		struct device *dev = to_device(entry);
+	while (!list_empty(&dpm_list)) {
+		struct device *dev = to_device(dpm_list.prev);
 
-		WARN_ON(dev->parent && dev->parent->power.sleeping);
-
-		dev->power.sleeping = true;
+		get_device(dev);
 		mutex_unlock(&dpm_list_mtx);
+
 		error = suspend_device(dev, state);
+
 		mutex_lock(&dpm_list_mtx);
 		if (error) {
 			printk(KERN_ERR "Could not suspend device %s: "
-					"error %d%s\n",
-					kobject_name(&dev->kobj),
-					error,
-					(error == -EAGAIN ?
-					" (please convert to suspend_late)" :
-					""));
-			dev->power.sleeping = false;
+				"error %d\n", kobject_name(&dev->kobj), error);
+			put_device(dev);
 			break;
 		}
+		dev->power.status = DPM_OFF;
 		if (!list_empty(&dev->power.entry))
-			list_move(&dev->power.entry, &dpm_off);
+			list_move(&dev->power.entry, &list);
+		put_device(dev);
 	}
-	if (!error)
-		all_sleeping = true;
+	list_splice(&list, dpm_list.prev);
 	mutex_unlock(&dpm_list_mtx);
+	return error;
+}
+
+/**
+ *	prepare_device - Execute the ->prepare() callback(s) for given device.
+ *	@dev:	Device.
+ *	@state: PM transition of the system being carried out.
+ */
+static int prepare_device(struct device *dev, pm_message_t state)
+{
+	int error = 0;
+
+	down(&dev->sem);
+
+	if (dev->bus && dev->bus->pm && dev->bus->pm->base.prepare) {
+		pm_dev_dbg(dev, state, "preparing ");
+		error = dev->bus->pm->base.prepare(dev);
+		suspend_report_result(dev->bus->pm->base.prepare, error);
+		if (error)
+			goto End;
+	}
+
+	if (dev->type && dev->type->pm && dev->type->pm->prepare) {
+		pm_dev_dbg(dev, state, "preparing type ");
+		error = dev->type->pm->prepare(dev);
+		suspend_report_result(dev->type->pm->prepare, error);
+		if (error)
+			goto End;
+	}
+
+	if (dev->class && dev->class->pm && dev->class->pm->prepare) {
+		pm_dev_dbg(dev, state, "preparing class ");
+		error = dev->class->pm->prepare(dev);
+		suspend_report_result(dev->class->pm->prepare, error);
+	}
+ End:
+	up(&dev->sem);
 
 	return error;
 }
 
 /**
+ *	dpm_prepare - Prepare all devices for a PM transition.
+ *	@state: PM transition of the system being carried out.
+ *
+ *	Execute the ->prepare() callback for all devices.
+ */
+static int dpm_prepare(pm_message_t state)
+{
+	struct list_head list;
+	int error = 0;
+
+	INIT_LIST_HEAD(&list);
+	mutex_lock(&dpm_list_mtx);
+	transition_started = true;
+	while (!list_empty(&dpm_list)) {
+		struct device *dev = to_device(dpm_list.next);
+
+		get_device(dev);
+		if (dev->power.status == DPM_INVALID) {
+			error = -EINVAL;
+			goto Error;
+		}
+		dev->power.status = DPM_PREPARING;
+		mutex_unlock(&dpm_list_mtx);
+
+		error = prepare_device(dev, state);
+
+		mutex_lock(&dpm_list_mtx);
+		if (error) {
+			dev->power.status = DPM_ON;
+			if (error == -EAGAIN) {
+				put_device(dev);
+				continue;
+			}
+ Error:
+			printk(KERN_ERR "Could not prepare device %s "
+				"for suspend: error %d\n",
+				kobject_name(&dev->kobj), error);
+			put_device(dev);
+			break;
+		}
+		dev->power.status = DPM_SUSPENDING;
+		if (!list_empty(&dev->power.entry))
+			list_move_tail(&dev->power.entry, &list);
+		put_device(dev);
+	}
+	list_splice(&list, &dpm_list);
+	mutex_unlock(&dpm_list_mtx);
+	return error;
+}
+
+/**
  *	device_suspend - Save state and stop all devices in system.
- *	@state: new power management state
+ *	@state: PM transition of the system being carried out.
  *
- *	Prevent new devices from being registered, then lock all devices
- *	and suspend them.
+ *	Prepare and suspend all devices.
  */
 int device_suspend(pm_message_t state)
 {
 	int error;
 
 	might_sleep();
-	error = dpm_suspend(state);
+	error = dpm_prepare(state);
+	if (!error)
+		error = dpm_suspend(state);
 	if (error)
-		device_resume();
+		device_resume(resume_event(state));
 	return error;
 }
 EXPORT_SYMBOL_GPL(device_suspend);
Index: linux-2.6/include/linux/device.h
===================================================================
--- linux-2.6.orig/include/linux/device.h
+++ linux-2.6/include/linux/device.h
@@ -69,6 +69,8 @@ struct bus_type {
 	int (*resume_early)(struct device *dev);
 	int (*resume)(struct device *dev);
 
+	struct pm_ext_ops *pm;
+
 	struct bus_type_private *p;
 };
 
@@ -132,6 +134,8 @@ struct device_driver {
 	int (*resume) (struct device *dev);
 	struct attribute_group **groups;
 
+	struct pm_ops *pm;
+
 	struct driver_private *p;
 };
 
@@ -202,6 +206,8 @@ struct class {
 
 	int (*suspend)(struct device *dev, pm_message_t state);
 	int (*resume)(struct device *dev);
+
+	struct pm_ops *pm;
 };
 
 extern int __must_check class_register(struct class *class);
@@ -345,8 +351,11 @@ struct device_type {
 	struct attribute_group **groups;
 	int (*uevent)(struct device *dev, struct kobj_uevent_env *env);
 	void (*release)(struct device *dev);
+
 	int (*suspend)(struct device *dev, pm_message_t state);
 	int (*resume)(struct device *dev);
+
+	struct pm_ops *pm;
 };
 
 /* interface for exporting device attributes */
Index: linux-2.6/kernel/power/disk.c
===================================================================
--- linux-2.6.orig/kernel/power/disk.c
+++ linux-2.6/kernel/power/disk.c
@@ -193,6 +193,7 @@ static int create_image(int platform_mod
 	if (error)
 		return error;
 
+	device_pm_lock();
 	local_irq_disable();
 	/* At this point, device_suspend() has been called, but *not*
 	 * device_power_down(). We *must* call device_power_down() now.
@@ -224,9 +225,10 @@ static int create_image(int platform_mod
 	/* NOTE:  device_power_up() is just a resume() for devices
 	 * that suspended with irqs off ... no overall powerup.
 	 */
-	device_power_up();
+	device_power_up(in_suspend ? PMSG_RECOVER : PMSG_RESTORE);
  Enable_irqs:
 	local_irq_enable();
+	device_pm_unlock();
 	return error;
 }
 
@@ -280,7 +282,7 @@ int hibernation_snapshot(int platform_mo
  Finish:
 	platform_finish(platform_mode);
  Resume_devices:
-	device_resume();
+	device_resume(in_suspend ? PMSG_RECOVER : PMSG_RESTORE);
  Resume_console:
 	resume_console();
  Close:
@@ -300,8 +302,9 @@ static int resume_target_kernel(void)
 {
 	int error;
 
+	device_pm_lock();
 	local_irq_disable();
-	error = device_power_down(PMSG_PRETHAW);
+	error = device_power_down(PMSG_QUIESCE);
 	if (error) {
 		printk(KERN_ERR "PM: Some devices failed to power down, "
 			"aborting resume\n");
@@ -329,9 +332,10 @@ static int resume_target_kernel(void)
 	swsusp_free();
 	restore_processor_state();
 	touch_softlockup_watchdog();
-	device_power_up();
+	device_power_up(PMSG_THAW);
  Enable_irqs:
 	local_irq_enable();
+	device_pm_unlock();
 	return error;
 }
 
@@ -350,7 +354,7 @@ int hibernation_restore(int platform_mod
 
 	pm_prepare_console();
 	suspend_console();
-	error = device_suspend(PMSG_PRETHAW);
+	error = device_suspend(PMSG_QUIESCE);
 	if (error)
 		goto Finish;
 
@@ -362,7 +366,7 @@ int hibernation_restore(int platform_mod
 		enable_nonboot_cpus();
 	}
 	platform_restore_cleanup(platform_mode);
-	device_resume();
+	device_resume(PMSG_RECOVER);
  Finish:
 	resume_console();
 	pm_restore_console();
@@ -403,6 +407,7 @@ int hibernation_platform_enter(void)
 	if (error)
 		goto Finish;
 
+	device_pm_lock();
 	local_irq_disable();
 	error = device_power_down(PMSG_HIBERNATE);
 	if (!error) {
@@ -411,6 +416,7 @@ int hibernation_platform_enter(void)
 		while (1);
 	}
 	local_irq_enable();
+	device_pm_unlock();
 
 	/*
 	 * We don't need to reenable the nonboot CPUs or resume consoles, since
@@ -419,7 +425,7 @@ int hibernation_platform_enter(void)
  Finish:
 	hibernation_ops->finish();
  Resume_devices:
-	device_resume();
+	device_resume(PMSG_RESTORE);
  Resume_console:
 	resume_console();
  Close:
Index: linux-2.6/kernel/power/main.c
===================================================================
--- linux-2.6.orig/kernel/power/main.c
+++ linux-2.6/kernel/power/main.c
@@ -228,6 +228,7 @@ static int suspend_enter(suspend_state_t
 {
 	int error = 0;
 
+	device_pm_lock();
 	arch_suspend_disable_irqs();
 	BUG_ON(!irqs_disabled());
 
@@ -239,10 +240,11 @@ static int suspend_enter(suspend_state_t
 	if (!suspend_test(TEST_CORE))
 		error = suspend_ops->enter(state);
 
-	device_power_up();
+	device_power_up(PMSG_RESUME);
  Done:
 	arch_suspend_enable_irqs();
 	BUG_ON(irqs_disabled());
+	device_pm_unlock();
 	return error;
 }
 
@@ -291,7 +293,7 @@ int suspend_devices_and_enter(suspend_st
 	if (suspend_ops->finish)
 		suspend_ops->finish();
  Resume_devices:
-	device_resume();
+	device_resume(PMSG_RESUME);
  Resume_console:
 	resume_console();
  Close:
Index: linux-2.6/arch/x86/kernel/apm_32.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/apm_32.c
+++ linux-2.6/arch/x86/kernel/apm_32.c
@@ -1208,9 +1208,9 @@ static int suspend(int vetoable)
 	if (err != APM_SUCCESS)
 		apm_error("suspend", err);
 	err = (err == APM_SUCCESS) ? 0 : -EIO;
-	device_power_up();
+	device_power_up(PMSG_RESUME);
 	local_irq_enable();
-	device_resume();
+	device_resume(PMSG_RESUME);
 	queue_event(APM_NORMAL_RESUME, NULL);
  out:
 	spin_lock(&user_list_lock);
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
@@ -4,7 +4,7 @@
  * main.c
  */
 
-extern struct list_head dpm_active;	/* The active device list */
+extern struct list_head dpm_list;	/* The active device list */
 
 static inline struct device *to_device(struct list_head *entry)
 {
Index: linux-2.6/drivers/base/power/trace.c
===================================================================
--- linux-2.6.orig/drivers/base/power/trace.c
+++ linux-2.6/drivers/base/power/trace.c
@@ -188,9 +188,9 @@ static int show_file_hash(unsigned int v
 static int show_dev_hash(unsigned int value)
 {
 	int match = 0;
-	struct list_head * entry = dpm_active.prev;
+	struct list_head *entry = dpm_list.prev;
 
-	while (entry != &dpm_active) {
+	while (entry != &dpm_list) {
 		struct device * dev = to_device(entry);
 		unsigned int hash = hash_string(DEVSEED, dev->bus_id, DEVHASH);
 		if (hash == value) {

[RFC][PATCH] PM: Introduce new top level suspend and hibernation callbacks (rev. 6)

[Rafael J. Wysocki]

On Sunday, 30 of March 2008, Rafael J. Wysocki wrote:
> On Saturday, 29 of March 2008, Rafael J. Wysocki wrote:
> > From: Rafael J. Wysocki <rjw@sisk.pl>
> > 
> > Introduce 'struct pm_ops' and 'struct pm_ext_ops' representing
> > suspend and hibernation operations for bus types, device classes and
> > device types.
> > 
> > Modify the PM core to use 'struct pm_ops' and 'struct pm_ext_ops'
> > objects, if defined, instead of the ->suspend() and ->resume() or,
> > respectively, ->suspend_late() and ->resume_early() callbacks that
> > will be considered as legacy and gradually phased out.
> 
> Unfortunately I forgot to set dev->power.status to DPM_PREPARING before
> calling ->prepare(), as documented.  Also, dpm_prepare() could cleaned up
> a bit.
> 
> Fixed patch follows.

My testing shows that some drivers tend to return error codes from their
->resume() callbacks, even though the devices in question appear to work
correctly after the seemingly failing suspend.

For this reason, I have changed the patch so that the "invalid" status of
devices is cleared by the PM core in dpm_complete().  I have also added
messages printed during a resume if an error is returned by a driver's
callback.

Thanks,
Rafael

---
From: Rafael J. Wysocki <rjw@sisk.pl>

Introduce 'struct pm_ops' and 'struct pm_ext_ops' representing
suspend and hibernation operations for bus types, device classes and
device types.

Modify the PM core to use 'struct pm_ops' and 'struct pm_ext_ops'
objects, if defined, instead of the ->suspend() and ->resume() or,
respectively, ->suspend_late() and ->resume_early() callbacks that
will be considered as legacy and gradually phased out.

Change the behavior of the PM core wrt the error codes returned by
device drivers' ->resume() callbacks.  Namely, if an error code
is returned by one of them, the device for which it's been returned
is regarded as "invalid" by the PM core which will refuse to handle
it from that point on (in particualr, suspend/hibernation will not
be started if there is an "invalid" device in the system).

The main purpose of doing this is to separate suspend (aka S2RAM and
standby) callbacks from hibernation callbacks in such a way that the
new callbacks won't take arguments and the semantics of each of them
will be clearly specified.  This has been requested for multiple
times by many people, including Linus himself, and the reason is that
within the current scheme if ->resume() is called, for example, it's
difficult to say why it's been called (ie. is it a resume from RAM or
from hibernation or a suspend/hibernation failure etc.?).

The second purpose is to make the suspend/hibernation callbacks more
flexible so that device drivers can handle more than they can within
the current scheme.  For example, some drivers may need to prevent
new children of the device from being registered before their
->suspend() callbacks are executed or they may want to carry out some
operations requiring the availability of some other devices, not
directly bound via the parent-child relationship, in order to prepare
for the execution of ->suspend(), etc.

Ultimately, we'd like to stop using the freezing of tasks for suspend
and therefore the drivers' suspend/hibernation code will have to take
care of the handling of the user space during suspend/hibernation.
That, in turn, would be difficult within the current scheme, without
the new ->prepare() and ->complete() callbacks.

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

 arch/x86/kernel/apm_32.c   |    4 
 drivers/base/power/main.c  |  706 ++++++++++++++++++++++++++++++++++-----------
 drivers/base/power/power.h |    2 
 drivers/base/power/trace.c |    4 
 include/linux/device.h     |    9 
 include/linux/pm.h         |  318 ++++++++++++++++++--
 kernel/power/disk.c        |   20 -
 kernel/power/main.c        |    6 
 8 files changed, 870 insertions(+), 199 deletions(-)

Index: linux-2.6/include/linux/pm.h
===================================================================
--- linux-2.6.orig/include/linux/pm.h
+++ linux-2.6/include/linux/pm.h
@@ -114,7 +114,9 @@ typedef struct pm_message {
 	int event;
 } pm_message_t;
 
-/*
+/**
+ * struct pm_ops - device PM callbacks
+ *
  * Several driver power state transitions are externally visible, affecting
  * the state of pending I/O queues and (for drivers that touch hardware)
  * interrupts, wakeups, DMA, and other hardware state.  There may also be
@@ -122,6 +124,288 @@ typedef struct pm_message {
  * to the rest of the driver stack (such as a driver that's ON gating off
  * clocks which are not in active use).
  *
+ * The externally visible transitions are handled with the help of the following
+ * callbacks included in this structure:
+ *
+ * @prepare: Prepare the device for the upcoming transition, but do NOT change
+ *	its hardware state.  Prevent new children of the device from being
+ *	registered after @prepare() returns (the driver's subsystem and
+ *	generally the rest of the kernel is supposed to prevent new calls to the
+ *	probe method from being made too once @prepare() has succeeded).  If
+ *	@prepare() detects a situation it cannot handle (e.g. registration of a
+ *	child already in progress), it may return -EAGAIN, so that the PM core
+ *	can execute it once again (e.g. after the new child has 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 @prepare() for all devices before starting to
+ *	execute suspend callbacks for any of them, so drivers may assume all of
+ *	the other devices to be present and functional while @prepare() is being
+ *	executed.  In particular, it is safe to make GFP_KERNEL memory
+ *	allocations from within @prepare(), although they are likely to fail in
+ *	case of hibernation, if a substantial amount of memory is requested.
+ *	However, drivers may NOT assume anything about the availability of the
+ *	user space at that time and it is not correct to request firmware from
+ *	within @prepare() (it's too late to do that).
+ *
+ * @complete: Undo the changes made by @prepare().  This method is executed for
+ *	all kinds of resume transitions, following one of the resume callbacks:
+ *	@resume(), @thaw(), @restore().  Also called if the state transition
+ *	fails before the driver's suspend callback (@suspend(), @freeze(),
+ *	@poweroff()) can be executed (e.g. if the suspend callback fails for one
+ *	of the other devices that the PM core has unsucessfully attempted to
+ *	suspend earlier).
+ *	The PM core executes @complete() after it has executed the appropriate
+ *	resume callback for all devices.
+ *
+ * @suspend: Executed before putting the system into a sleep state in which the
+ *	contents of main memory are preserved.  Quiesce the device, put it into
+ *	a low power state appropriate for the upcoming system state (such as
+ *	PCI_D3hot), and enable wakeup events as appropriate.
+ *
+ * @resume: Executed after waking the system up from a sleep state in which the
+ *	contents of main memory were preserved.  Put the device into the
+ *	appropriate state, according to the information saved in memory by the
+ *	preceding @suspend().  The driver starts working again, responding to
+ *	hardware events and software requests.  The hardware may have gone
+ *	through a power-off reset, or it may have maintained state from the
+ *	previous suspend() which the driver may rely on while resuming.  On most
+ *	platforms, there are no restrictions on availability of resources like
+ *	clocks during @resume().
+ *
+ * @freeze: Hibernation-specific, executed before creating a hibernation image.
+ *	Quiesce operations so that a consistent image can be created, but do NOT
+ *	otherwise put the device into a low power device state and do NOT emit
+ *	system wakeup events.  Save in main memory the device settings to be
+ *	used by @restore() during the subsequent resume from hibernation or by
+ *	the subsequent @thaw(), if the creation of the image or the restoration
+ *	of main memory contents from it fails.
+ *
+ * @thaw: Hibernation-specific, executed after creating a hibernation image OR
+ *	if the creation of the image fails.  Also executed after a failing
+ *	attempt to restore the contents of main memory from such an image.
+ *	Undo the changes made by the preceding @freeze(), so the device can be
+ *	operated in the same way as immediately before the call to @freeze().
+ *
+ * @poweroff: Hibernation-specific, executed after saving a hibernation image.
+ *	Quiesce the device, put it into a low power state appropriate for the
+ *	upcoming system state (such as PCI_D3hot), and enable wakeup events as
+ *	appropriate.
+ *
+ * @restore: Hibernation-specific, executed after restoring the contents of main
+ *	memory from a hibernation image.  Driver starts working again,
+ *	responding to hardware events and software requests.  Drivers may NOT
+ *	make ANY assumptions about the hardware state right prior to @restore().
+ *	On most platforms, there are no restrictions on availability of
+ *	resources like clocks during @restore().
+ *
+ * All of the above callbacks, except for @complete(), return error codes.
+ * However, the error codes returned by the resume operations, @resume(),
+ * @thaw(), and @restore(), do not cause the PM core to abort the resume
+ * transition during which they are returned.  Instead, the PM core marks
+ * the devices for which they are returned and all of their children as
+ * "invalid" and doesn't attempt to execute any other suspend/hibernation
+ * callbacks for them (including @complete()).  For now, during the completion
+ * phase of resume the PM core clears the "invalid" status of devices (this is
+ * done only because the legacy ->resume() callbacks of some drivers tend to
+ * return errors even if the "failing" devices work correctly after the
+ * resume).  Note, however, that this is going to change in the future.
+ *
+ * It is allowed to unregister devices while the above callbacks are being
+ * executed.  However, it is not allowed to unregister a device from within any
+ * of its own callbacks.
+ */
+
+struct pm_ops {
+	int (*prepare)(struct device *dev);
+	void (*complete)(struct device *dev);
+	int (*suspend)(struct device *dev);
+	int (*resume)(struct device *dev);
+	int (*freeze)(struct device *dev);
+	int (*thaw)(struct device *dev);
+	int (*poweroff)(struct device *dev);
+	int (*restore)(struct device *dev);
+};
+
+/**
+ * struct pm_ext_ops - extended device PM callbacks
+ *
+ * Some devices require certain operations related to suspend and hibernation
+ * to be carried out with interrupts disabled.  Thus, 'struct pm_ext_ops' below
+ * is defined, adding callbacks to be executed with interrupts disabled to
+ * 'struct pm_ops'.
+ *
+ * The following callbacks included in 'struct pm_ext_ops' are executed with
+ * the nonboot CPUs switched off and with interrupts disabled on the only
+ * functional CPU.  They also are executed with the PM core list of devices
+ * locked, so they must NOT unregister any devices.
+ *
+ * @suspend_noirq: Complete the operations of ->suspend() by carrying out any
+ *	actions required for suspending the device that need interrupts to be
+ *	disabled
+ *
+ * @resume_noirq: Prepare for the execution of ->resume() by carrying out any
+ *	actions required for resuming the device that need interrupts to be
+ *	disabled
+ *
+ * @freeze_noirq: Complete the operations of ->freeze() by carrying out any
+ *	actions required for freezing the device that need interrupts to be
+ *	disabled
+ *
+ * @thaw_noirq: Prepare for the execution of ->thaw() by carrying out any
+ *	actions required for thawing the device that need interrupts to be
+ *	disabled
+ *
+ * @poweroff_noirq: Complete the operations of ->poweroff() by carrying out any
+ *	actions required for handling the device that need interrupts to be
+ *	disabled
+ *
+ * @restore_noirq: Prepare for the execution of ->restore() by carrying out any
+ *	actions required for restoring the operations of the device that need
+ *	interrupts to be disabled
+ *
+ * All of the above callbacks return error codes, but the error codes returned
+ * by the resume operations, @resume_noirq(), @thaw_noirq(), and
+ * @restore_noirq(), do not cause the PM core to abort the resume transition
+ * during which they are returned.  Instead, the PM core marks the devices for
+ * which they are returned and all of their children as "invalid" and doesn't
+ * attempt to execute any resume callbacks for them (including ->complete()).
+ */
+
+struct pm_ext_ops {
+	struct pm_ops base;
+	int (*suspend_noirq)(struct device *dev);
+	int (*resume_noirq)(struct device *dev);
+	int (*freeze_noirq)(struct device *dev);
+	int (*thaw_noirq)(struct device *dev);
+	int (*poweroff_noirq)(struct device *dev);
+	int (*restore_noirq)(struct device *dev);
+};
+
+/**
+ * PM_EVENT_ messages
+ *
+ * The following PM_EVENT_ messages are defined for the internal use of the PM
+ * core, in order to provide a mechanism allowing the high level suspend and
+ * hibernation code to convey the necessary information to the device PM core
+ * code:
+ *
+ * ON		No transition.
+ *
+ * FREEZE 	System is going to hibernate, call ->prepare() and ->freeze()
+ *		for all devices.
+ *
+ * SUSPEND	System is going to suspend, call ->prepare() and ->suspend()
+ *		for all devices.
+ *
+ * HIBERNATE	Hibernation image has been saved, call ->prepare() and
+ *		->poweroff() for all devices.
+ *
+ * QUIESCE	Contents of main memory are going to be restored from a (loaded)
+ *		hibernation image, call ->prepare() and ->freeze() for all
+ *		devices.
+ *
+ * RESUME	System is resuming, call ->resume() and ->complete() for all
+ *		devices.
+ *
+ * THAW		Hibernation image has been created, call ->thaw() and
+ *		->complete() for all devices.
+ *
+ * RESTORE	Contents of main memory have been restored from a hibernation
+ *		image, call ->restore() and ->complete() for all devices.
+ *
+ * RECOVER	Creation of a hibernation image or restoration of the main
+ *		memory contents from a hibernation image has failed, call
+ *		->thaw() and ->complete() for all devices.
+ */
+
+#define PM_EVENT_ON		0x0000
+#define PM_EVENT_FREEZE 	0x0001
+#define PM_EVENT_SUSPEND	0x0002
+#define PM_EVENT_HIBERNATE	0x0004
+#define PM_EVENT_QUIESCE	0x0008
+#define PM_EVENT_RESUME		0x0010
+#define PM_EVENT_THAW		0x0020
+#define PM_EVENT_RESTORE	0x0040
+#define PM_EVENT_RECOVER	0x0080
+
+#define PM_EVENT_SLEEP	(PM_EVENT_SUSPEND | PM_EVENT_HIBERNATE)
+
+#define PMSG_FREEZE	((struct pm_message){ .event = PM_EVENT_FREEZE, })
+#define PMSG_QUIESCE	((struct pm_message){ .event = PM_EVENT_QUIESCE, })
+#define PMSG_SUSPEND	((struct pm_message){ .event = PM_EVENT_SUSPEND, })
+#define PMSG_HIBERNATE	((struct pm_message){ .event = PM_EVENT_HIBERNATE, })
+#define PMSG_RESUME	((struct pm_message){ .event = PM_EVENT_RESUME, })
+#define PMSG_THAW	((struct pm_message){ .event = PM_EVENT_THAW, })
+#define PMSG_RESTORE	((struct pm_message){ .event = PM_EVENT_RESTORE, })
+#define PMSG_RECOVER	((struct pm_message){ .event = PM_EVENT_RECOVER, })
+#define PMSG_ON		((struct pm_message){ .event = PM_EVENT_ON, })
+
+/**
+ * Device power management states
+ *
+ * These state labels are used internally by the PM core to indicate the current
+ * status of a device with respect to the PM core operations.
+ *
+ * DPM_INVALID		Device is not in a consistent state.  Set when one of
+ *			the device's resume callbacks, ->resume(), ->thaw(),
+ *			->restore(), ->resume()_noirq, ->thaw_noirq(), or
+ *			->restore_noirq(), fails.  Also set when the device
+ *			parent's status turns out to be DPM_INVALID.
+ *
+ * DPM_ON		Device is regarded as operational.  Set this way
+ *			initially and when ->complete() is about to be called.
+ *			Also set when ->prepare() fails.
+ *
+ * DPM_PREPARING	Device is going to be prepared for a PM transition.  Set
+ *			when ->prepare() is about to be called.
+ *
+ * DPM_RESUMING		Device is going to be resumed.  Set when ->resume(),
+ *			->thaw(), or ->restore() is about to be called.
+ *
+ * DPM_SUSPENDING	Device has been prepared for a power transition.  Set
+ *			when ->prepare() has just succeeded.
+ *
+ * DPM_OFF		Device is regarded as inactive.  Set immediately after
+ *			->suspend(), ->freeze(), or ->poweroff() has succeeded.
+ *			Also set when ->resume()_noirq, ->thaw_noirq(), or
+ *			->restore_noirq() is about to be called.
+ *
+ * DPM_OFF_IRQ		Device is in a "deep sleep".  Set immediately after
+ *			->suspend_noirq(), ->freeze_noirq(), or
+ *			->poweroff_noirq() has just succeeded.
+ */
+
+enum dpm_state {
+	DPM_INVALID,
+	DPM_ON,
+	DPM_PREPARING,
+	DPM_RESUMING,
+	DPM_SUSPENDING,
+	DPM_OFF,
+	DPM_OFF_IRQ,
+};
+
+struct dev_pm_info {
+	pm_message_t		power_state;
+	unsigned		can_wakeup:1;
+	unsigned		should_wakeup:1;
+	enum dpm_state		status;		/* Owned by the PM core */
+#ifdef	CONFIG_PM_SLEEP
+	struct list_head	entry;
+#endif
+};
+
+/*
+ * The PM_EVENT_ messages are also used by drivers implementing the legacy
+ * suspend framework, based on the ->suspend() and ->resume() callbacks common
+ * for suspend and hibernation transitions, according to the rules below.
+ */
+
+/* Necessary, because several drivers use PM_EVENT_PRETHAW */
+#define PM_EVENT_PRETHAW PM_EVENT_QUIESCE
+
+/*
  * One transition is triggered by resume(), after a suspend() call; the
  * message is implicit:
  *
@@ -166,35 +450,13 @@ typedef struct pm_message {
  * or from system low-power states such as standby or suspend-to-RAM.
  */
 
-#define PM_EVENT_ON 0
-#define PM_EVENT_FREEZE 1
-#define PM_EVENT_SUSPEND 2
-#define PM_EVENT_HIBERNATE 4
-#define PM_EVENT_PRETHAW 8
-
-#define PM_EVENT_SLEEP	(PM_EVENT_SUSPEND | PM_EVENT_HIBERNATE)
-
-#define PMSG_FREEZE	((struct pm_message){ .event = PM_EVENT_FREEZE, })
-#define PMSG_PRETHAW	((struct pm_message){ .event = PM_EVENT_PRETHAW, })
-#define PMSG_SUSPEND	((struct pm_message){ .event = PM_EVENT_SUSPEND, })
-#define PMSG_HIBERNATE	((struct pm_message){ .event = PM_EVENT_HIBERNATE, })
-#define PMSG_ON		((struct pm_message){ .event = PM_EVENT_ON, })
-
-struct dev_pm_info {
-	pm_message_t		power_state;
-	unsigned		can_wakeup:1;
-	unsigned		should_wakeup:1;
-	bool			sleeping:1;	/* Owned by the PM core */
-#ifdef	CONFIG_PM_SLEEP
-	struct list_head	entry;
-#endif
-};
+#ifdef CONFIG_PM_SLEEP
+extern void device_pm_lock(void);
+extern void device_power_up(pm_message_t state);
+extern void device_resume(pm_message_t state);
 
+extern void device_pm_unlock(void);
 extern int device_power_down(pm_message_t state);
-extern void device_power_up(void);
-extern void device_resume(void);
-
-#ifdef CONFIG_PM_SLEEP
 extern int device_suspend(pm_message_t state);
 extern int device_prepare_suspend(pm_message_t state);
 
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
@@ -12,11 +12,9 @@
  * and add it to the list of power-controlled devices. sysfs entries for
  * controlling device power management will also be added.
  *
- * A different set of lists than the global subsystem list are used to
- * keep track of power info because we use different lists to hold
- * devices based on what stage of the power management process they
- * are in. The power domain dependencies may also differ from the
- * ancestral dependencies that the subsystem list maintains.
+ * A separate list is used for keeping track of power info, because the power
+ * domain dependencies may differ from the ancestral dependencies that the
+ * subsystem list maintains.
  */
 
 #include <linux/device.h>
@@ -30,31 +28,40 @@
 #include "power.h"
 
 /*
- * The entries in the dpm_active list are in a depth first order, simply
+ * The entries in the dpm_list list are in a depth first order, simply
  * because children are guaranteed to be discovered after parents, and
  * are inserted at the back of the list on discovery.
  *
- * All the other lists are kept in the same order, for consistency.
- * However the lists aren't always traversed in the same order.
- * Semaphores must be acquired from the top (i.e., front) down
- * and released in the opposite order.  Devices must be suspended
- * from the bottom (i.e., end) up and resumed in the opposite order.
- * That way no parent will be suspended while it still has an active
- * child.
- *
  * Since device_pm_add() may be called with a device semaphore held,
  * we must never try to acquire a device semaphore while holding
  * dpm_list_mutex.
  */
 
-LIST_HEAD(dpm_active);
-static LIST_HEAD(dpm_off);
-static LIST_HEAD(dpm_off_irq);
+LIST_HEAD(dpm_list);
 
 static DEFINE_MUTEX(dpm_list_mtx);
 
-/* 'true' if all devices have been suspended, protected by dpm_list_mtx */
-static bool all_sleeping;
+/*
+ * Set once the preparation of devices for a PM transition has started, reset
+ * before starting to resume devices.  Protected by dpm_list_mtx.
+ */
+static bool transition_started;
+
+/**
+ *	device_pm_lock - lock the list of active devices used by the PM core
+ */
+void device_pm_lock(void)
+{
+	mutex_lock(&dpm_list_mtx);
+}
+
+/**
+ *	device_pm_unlock - unlock the list of active devices used by the PM core
+ */
+void device_pm_unlock(void)
+{
+	mutex_unlock(&dpm_list_mtx);
+}
 
 /**
  *	device_pm_add - add a device to the list of active devices
@@ -68,22 +75,36 @@ int device_pm_add(struct device *dev)
 		 dev->bus ? dev->bus->name : "No Bus",
 		 kobject_name(&dev->kobj));
 	mutex_lock(&dpm_list_mtx);
-	if ((dev->parent && dev->parent->power.sleeping) || all_sleeping) {
-		if (dev->parent->power.sleeping)
-			dev_warn(dev,
-				"parent %s is sleeping, will not add\n",
+	if (dev->parent) {
+		if (dev->parent->power.status == DPM_INVALID) {
+			dev_warn(dev, "state of parent %s is inconsistent, "
+				"will not add\n", dev->parent->bus_id);
+			goto Refuse;
+		} else if (dev->parent->power.status >= DPM_SUSPENDING) {
+			dev_warn(dev, "parent %s is sleeping, will not add\n",
 				dev->parent->bus_id);
-		else
-			dev_warn(dev, "devices are sleeping, will not add\n");
-		WARN_ON(true);
-		error = -EBUSY;
-	} else {
-		error = dpm_sysfs_add(dev);
-		if (!error)
-			list_add_tail(&dev->power.entry, &dpm_active);
+			goto Refuse;
+		}
+	} else if (transition_started) {
+		/*
+		 * We refuse to register parentless devices while a PM
+		 * transition is in progress in order to avoid leaving them
+		 * unhandled down the road
+		 */
+		goto Refuse;
+	}
+	error = dpm_sysfs_add(dev);
+	if (!error) {
+		dev->power.status = DPM_ON;
+		list_add_tail(&dev->power.entry, &dpm_list);
 	}
+ End:
 	mutex_unlock(&dpm_list_mtx);
 	return error;
+ Refuse:
+	WARN_ON(true);
+	error = -EBUSY;
+	goto End;
 }
 
 /**
@@ -99,77 +120,250 @@ void device_pm_remove(struct device *dev
 		 kobject_name(&dev->kobj));
 	mutex_lock(&dpm_list_mtx);
 	dpm_sysfs_remove(dev);
+	dev->power.status = DPM_INVALID;
 	list_del_init(&dev->power.entry);
 	mutex_unlock(&dpm_list_mtx);
 }
 
+/**
+ *	pm_op - execute the PM operation appropiate for given PM event
+ *	@dev:	Device.
+ *	@ops:	PM operations to choose from.
+ *	@state:	PM transition of the system being carried out.
+ */
+static int pm_op(struct device *dev, struct pm_ops *ops, pm_message_t state)
+{
+	int error = 0;
+
+	switch (state.event) {
+#ifdef CONFIG_SUSPEND
+	case PM_EVENT_SUSPEND:
+		if (ops->suspend) {
+			error = ops->suspend(dev);
+			suspend_report_result(ops->suspend, error);
+		}
+		break;
+	case PM_EVENT_RESUME:
+		if (ops->resume) {
+			error = ops->resume(dev);
+			suspend_report_result(ops->resume, error);
+		}
+		break;
+#endif /* CONFIG_SUSPEND */
+#ifdef CONFIG_HIBERNATION
+	case PM_EVENT_FREEZE:
+	case PM_EVENT_QUIESCE:
+		if (ops->freeze) {
+			error = ops->freeze(dev);
+			suspend_report_result(ops->freeze, error);
+		}
+		break;
+	case PM_EVENT_HIBERNATE:
+		if (ops->poweroff) {
+			error = ops->poweroff(dev);
+			suspend_report_result(ops->poweroff, error);
+		}
+		break;
+	case PM_EVENT_THAW:
+	case PM_EVENT_RECOVER:
+		if (ops->thaw) {
+			error = ops->thaw(dev);
+			suspend_report_result(ops->thaw, error);
+		}
+		break;
+	case PM_EVENT_RESTORE:
+		if (ops->restore) {
+			error = ops->restore(dev);
+			suspend_report_result(ops->restore, error);
+		}
+		break;
+#endif /* CONFIG_HIBERNATION */
+	default:
+		error = -EINVAL;
+	}
+	return error;
+}
+
+/**
+ *	pm_noirq_op - execute the PM operation appropiate for given PM event
+ *	@dev:	Device.
+ *	@ops:	PM operations to choose from.
+ *	@state: PM transition of the system being carried out.
+ *
+ *	The operation is executed with interrupts disabled by the only remaining
+ *	functional CPU in the system.
+ */
+static int pm_noirq_op(struct device *dev, struct pm_ext_ops *ops,
+			pm_message_t state)
+{
+	int error = 0;
+
+	switch (state.event) {
+#ifdef CONFIG_SUSPEND
+	case PM_EVENT_SUSPEND:
+		if (ops->suspend_noirq) {
+			error = ops->suspend_noirq(dev);
+			suspend_report_result(ops->suspend_noirq, error);
+		}
+		break;
+	case PM_EVENT_RESUME:
+		if (ops->resume_noirq) {
+			error = ops->resume_noirq(dev);
+			suspend_report_result(ops->resume_noirq, error);
+		}
+		break;
+#endif /* CONFIG_SUSPEND */
+#ifdef CONFIG_HIBERNATION
+	case PM_EVENT_FREEZE:
+	case PM_EVENT_QUIESCE:
+		if (ops->freeze_noirq) {
+			error = ops->freeze_noirq(dev);
+			suspend_report_result(ops->freeze_noirq, error);
+		}
+		break;
+	case PM_EVENT_HIBERNATE:
+		if (ops->poweroff_noirq) {
+			error = ops->poweroff_noirq(dev);
+			suspend_report_result(ops->poweroff_noirq, error);
+		}
+		break;
+	case PM_EVENT_THAW:
+	case PM_EVENT_RECOVER:
+		if (ops->thaw_noirq) {
+			error = ops->thaw_noirq(dev);
+			suspend_report_result(ops->thaw_noirq, error);
+		}
+		break;
+	case PM_EVENT_RESTORE:
+		if (ops->restore_noirq) {
+			error = ops->restore_noirq(dev);
+			suspend_report_result(ops->restore_noirq, error);
+		}
+		break;
+#endif /* CONFIG_HIBERNATION */
+	default:
+		error = -EINVAL;
+	}
+	return error;
+}
+
+static char *pm_verb(int event)
+{
+	switch (event) {
+	case PM_EVENT_SUSPEND:
+		return "suspend";
+	case PM_EVENT_RESUME:
+		return "resume";
+	case PM_EVENT_FREEZE:
+		return "freeze";
+	case PM_EVENT_QUIESCE:
+		return "quiesce";
+	case PM_EVENT_HIBERNATE:
+		return "hibernate";
+	case PM_EVENT_THAW:
+		return "thaw";
+	case PM_EVENT_RESTORE:
+		return "restore";
+	default:
+		return "(unknown PM event)";
+	}
+}
+
+static void pm_dev_dbg(struct device *dev, pm_message_t state, char *info)
+{
+	dev_dbg(dev, "%s%s%s\n", info, pm_verb(state.event),
+		((state.event & PM_EVENT_SLEEP) && device_may_wakeup(dev)) ?
+		", may wakeup" : "");
+}
+
 /*------------------------- Resume routines -------------------------*/
 
 /**
- *	resume_device_early - Power on one device (early resume).
+ *	resume_device_noirq - Power on one device (early resume).
  *	@dev:	Device.
+ *	@state: PM transition of the system being carried out.
  *
  *	Must be called with interrupts disabled.
  */
-static int resume_device_early(struct device *dev)
+static int resume_device_noirq(struct device *dev, pm_message_t state)
 {
 	int error = 0;
 
 	TRACE_DEVICE(dev);
 	TRACE_RESUME(0);
 
-	if (dev->bus && dev->bus->resume_early) {
-		dev_dbg(dev, "EARLY resume\n");
+	if (!dev->bus)
+		goto End;
+
+	if (dev->bus->pm) {
+		pm_dev_dbg(dev, state, "EARLY ");
+		error = pm_noirq_op(dev, dev->bus->pm, state);
+	} else if (dev->bus->resume_early) {
+		pm_dev_dbg(dev, state, "legacy EARLY ");
 		error = dev->bus->resume_early(dev);
 	}
-
+ End:
 	TRACE_RESUME(error);
 	return error;
 }
 
 /**
  *	dpm_power_up - Power on all regular (non-sysdev) devices.
+ *	@state: PM transition of the system being carried out.
  *
- *	Walk the dpm_off_irq list and power each device up. This
- *	is used for devices that required they be powered down with
- *	interrupts disabled. As devices are powered on, they are moved
- *	to the dpm_off list.
+ *	Execute the appropriate "noirq resume" callback for all devices marked
+ *	as DPM_OFF_IRQ.
  *
  *	Must be called with interrupts disabled and only one CPU running.
  */
-static void dpm_power_up(void)
+static void dpm_power_up(pm_message_t state)
 {
+	struct device *dev;
 
-	while (!list_empty(&dpm_off_irq)) {
-		struct list_head *entry = dpm_off_irq.next;
-		struct device *dev = to_device(entry);
-
-		list_move_tail(entry, &dpm_off);
-		resume_device_early(dev);
+	list_for_each_entry(dev, &dpm_list, power.entry) {
+		if (dev->parent && dev->parent->power.status == DPM_INVALID) {
+			printk(KERN_ERR "Refusing to resume device %s: "
+				"invalid state of parent %s\n",
+				kobject_name(&dev->kobj),
+				kobject_name(&dev->parent->kobj));
+			dev->power.status = DPM_INVALID;
+		} else if (dev->power.status > DPM_OFF) {
+			int error;
+
+			dev->power.status = DPM_OFF;
+			error = resume_device_noirq(dev, state);
+			if (error) {
+				printk(KERN_ERR "Could not resume device %s: "
+					"error %d\n", kobject_name(&dev->kobj),
+					error);
+				dev->power.status = DPM_INVALID;
+			}
+		}
 	}
 }
 
 /**
  *	device_power_up - Turn on all devices that need special attention.
+ *	@state: PM transition of the system being carried out.
  *
  *	Power on system devices, then devices that required we shut them down
  *	with interrupts disabled.
  *
  *	Must be called with interrupts disabled.
  */
-void device_power_up(void)
+void device_power_up(pm_message_t state)
 {
 	sysdev_resume();
-	dpm_power_up();
+	dpm_power_up(state);
 }
 EXPORT_SYMBOL_GPL(device_power_up);
 
 /**
  *	resume_device - Restore state for one device.
  *	@dev:	Device.
- *
+ *	@state: PM transition of the system being carried out.
  */
-static int resume_device(struct device *dev)
+static int resume_device(struct device *dev, pm_message_t state)
 {
 	int error = 0;
 
@@ -178,21 +372,40 @@ static int resume_device(struct device *
 
 	down(&dev->sem);
 
-	if (dev->bus && dev->bus->resume) {
-		dev_dbg(dev,"resuming\n");
-		error = dev->bus->resume(dev);
+	if (dev->bus) {
+		if (dev->bus->pm) {
+			pm_dev_dbg(dev, state, "");
+			error = pm_op(dev, &dev->bus->pm->base, state);
+		} else if (dev->bus->resume) {
+			pm_dev_dbg(dev, state, "legacy ");
+			error = dev->bus->resume(dev);
+		}
+		if (error)
+			goto End;
 	}
 
-	if (!error && dev->type && dev->type->resume) {
-		dev_dbg(dev,"resuming\n");
-		error = dev->type->resume(dev);
+	if (dev->type) {
+		if (dev->type->pm) {
+			pm_dev_dbg(dev, state, "type ");
+			error = pm_op(dev, dev->type->pm, state);
+		} else if (dev->type->resume) {
+			pm_dev_dbg(dev, state, "legacy type ");
+			error = dev->type->resume(dev);
+		}
+		if (error)
+			goto End;
 	}
 
-	if (!error && dev->class && dev->class->resume) {
-		dev_dbg(dev,"class resume\n");
-		error = dev->class->resume(dev);
+	if (dev->class) {
+		if (dev->class->pm) {
+			pm_dev_dbg(dev, state, "class ");
+			error = pm_op(dev, dev->class->pm, state);
+		} else if (dev->class->resume) {
+			pm_dev_dbg(dev, state, "legacy class ");
+			error = dev->class->resume(dev);
+		}
 	}
-
+ End:
 	up(&dev->sem);
 
 	TRACE_RESUME(error);
@@ -201,78 +414,173 @@ static int resume_device(struct device *
 
 /**
  *	dpm_resume - Resume every device.
+ *	@state: PM transition of the system being carried out.
  *
- *	Resume the devices that have either not gone through
- *	the late suspend, or that did go through it but also
- *	went through the early resume.
+ *	Execute the appropriate "resume" callback for all devices the status of
+ *	which indicates that they are inactive.
+ */
+static void dpm_resume(pm_message_t state)
+{
+	struct list_head list;
+
+	INIT_LIST_HEAD(&list);
+	mutex_lock(&dpm_list_mtx);
+	transition_started = false;
+	while (!list_empty(&dpm_list)) {
+		struct device *dev = to_device(dpm_list.next);
+
+		get_device(dev);
+		if (dev->parent && dev->parent->power.status == DPM_INVALID) {
+			printk(KERN_ERR "Refusing to resume device %s: "
+				"invalid state of parent %s\n",
+				kobject_name(&dev->kobj),
+				kobject_name(&dev->parent->kobj));
+			dev->power.status = DPM_INVALID;
+		} else if (dev->power.status >= DPM_OFF) {
+			int error;
+
+			dev->power.status = DPM_RESUMING;
+			mutex_unlock(&dpm_list_mtx);
+
+			error = resume_device(dev, state);
+
+			mutex_lock(&dpm_list_mtx);
+			if (error) {
+				printk(KERN_ERR "Could not resume device %s: "
+					"error %d\n", kobject_name(&dev->kobj),
+					error);
+				dev->power.status = DPM_INVALID;
+			}
+		} else if (dev->power.status == DPM_SUSPENDING) {
+			/* Allow new children of the device to be registered */
+			dev->power.status = DPM_RESUMING;
+		}
+		if (!list_empty(&dev->power.entry))
+			list_move_tail(&dev->power.entry, &list);
+		put_device(dev);
+	}
+	list_splice(&list, &dpm_list);
+	mutex_unlock(&dpm_list_mtx);
+}
+
+/**
+ *	complete_device - Complete a PM transition for given device
+ *	@dev:	Device.
+ *	@state: PM transition of the system being carried out.
+ */
+static void complete_device(struct device *dev, pm_message_t state)
+{
+	down(&dev->sem);
+
+	if (dev->class && dev->class->pm && dev->class->pm->complete) {
+		pm_dev_dbg(dev, state, "completing class ");
+		dev->class->pm->complete(dev);
+	}
+
+	if (dev->type && dev->type->pm && dev->type->pm->complete) {
+		pm_dev_dbg(dev, state, "completing type ");
+		dev->type->pm->complete(dev);
+	}
+
+	if (dev->bus && dev->bus->pm && dev->bus->pm->base.complete) {
+		pm_dev_dbg(dev, state, "completing ");
+		dev->bus->pm->base.complete(dev);
+	}
+
+	up(&dev->sem);
+}
+
+/**
+ *	dpm_complete - Complete a PM transition for all devices.
+ *	@state: PM transition of the system being carried out.
  *
- *	Take devices from the dpm_off_list, resume them,
- *	and put them on the dpm_locked list.
+ *	Execute the ->complete() callbacks for all devices that are not marked
+ *	as DPM_ON.
  */
-static void dpm_resume(void)
+static void dpm_complete(pm_message_t state)
 {
+	struct list_head list;
+
+	INIT_LIST_HEAD(&list);
 	mutex_lock(&dpm_list_mtx);
-	all_sleeping = false;
-	while(!list_empty(&dpm_off)) {
-		struct list_head *entry = dpm_off.next;
-		struct device *dev = to_device(entry);
+	while (!list_empty(&dpm_list)) {
+		struct device *dev = to_device(dpm_list.prev);
 
-		list_move_tail(entry, &dpm_active);
-		dev->power.sleeping = false;
-		mutex_unlock(&dpm_list_mtx);
-		resume_device(dev);
-		mutex_lock(&dpm_list_mtx);
+		get_device(dev);
+		if (dev->power.status > DPM_ON) {
+			dev->power.status = DPM_ON;
+			mutex_unlock(&dpm_list_mtx);
+
+			complete_device(dev, state);
+
+			mutex_lock(&dpm_list_mtx);
+		} else if (dev->power.status == DPM_INVALID) {
+			dev->power.status = DPM_ON;
+		}
+		if (!list_empty(&dev->power.entry))
+			list_move(&dev->power.entry, &list);
+		put_device(dev);
 	}
+	list_splice(&list, &dpm_list);
 	mutex_unlock(&dpm_list_mtx);
 }
 
 /**
  *	device_resume - Restore state of each device in system.
+ *	@state: PM transition of the system being carried out.
  *
  *	Resume all the devices, unlock them all, and allow new
  *	devices to be registered once again.
  */
-void device_resume(void)
+void device_resume(pm_message_t state)
 {
 	might_sleep();
-	dpm_resume();
+	dpm_resume(state);
+	dpm_complete(state);
 }
 EXPORT_SYMBOL_GPL(device_resume);
 
 
 /*------------------------- Suspend routines -------------------------*/
 
-static inline char *suspend_verb(u32 event)
+/**
+ *	resume_event - return a PM message representing the resume event
+ *	               corresponding to given sleep state.
+ *	@sleep_state: PM message representing a sleep state.
+ */
+static pm_message_t resume_event(pm_message_t sleep_state)
 {
-	switch (event) {
-	case PM_EVENT_SUSPEND:	return "suspend";
-	case PM_EVENT_FREEZE:	return "freeze";
-	case PM_EVENT_PRETHAW:	return "prethaw";
-	default:		return "(unknown suspend event)";
+	switch (sleep_state.event) {
+	case PM_EVENT_SUSPEND:
+		return PMSG_RESUME;
+	case PM_EVENT_FREEZE:
+	case PM_EVENT_QUIESCE:
+		return PMSG_RECOVER;
+	case PM_EVENT_HIBERNATE:
+		return PMSG_RESTORE;
 	}
-}
-
-static void
-suspend_device_dbg(struct device *dev, pm_message_t state, char *info)
-{
-	dev_dbg(dev, "%s%s%s\n", info, suspend_verb(state.event),
-		((state.event == PM_EVENT_SUSPEND) && device_may_wakeup(dev)) ?
-		", may wakeup" : "");
+	return PMSG_ON;
 }
 
 /**
- *	suspend_device_late - Shut down one device (late suspend).
+ *	suspend_device_noirq - Shut down one device (late suspend).
  *	@dev:	Device.
- *	@state:	Power state device is entering.
+ *	@state: PM transition of the system being carried out.
  *
  *	This is called with interrupts off and only a single CPU running.
  */
-static int suspend_device_late(struct device *dev, pm_message_t state)
+static int suspend_device_noirq(struct device *dev, pm_message_t state)
 {
 	int error = 0;
 
-	if (dev->bus && dev->bus->suspend_late) {
-		suspend_device_dbg(dev, state, "LATE ");
+	if (!dev->bus)
+		return 0;
+
+	if (dev->bus->pm) {
+		pm_dev_dbg(dev, state, "LATE ");
+		error = pm_noirq_op(dev, dev->bus->pm, state);
+	} else if (dev->bus->suspend_late) {
+		pm_dev_dbg(dev, state, "legacy LATE ");
 		error = dev->bus->suspend_late(dev, state);
 		suspend_report_result(dev->bus->suspend_late, error);
 	}
@@ -281,37 +589,32 @@ static int suspend_device_late(struct de
 
 /**
  *	device_power_down - Shut down special devices.
- *	@state:		Power state to enter.
+ *	@state: PM transition of the system being carried out.
  *
- *	Power down devices that require interrupts to be disabled
- *	and move them from the dpm_off list to the dpm_off_irq list.
+ *	Power down devices that require interrupts to be disabled.
  *	Then power down system devices.
  *
  *	Must be called with interrupts disabled and only one CPU running.
  */
 int device_power_down(pm_message_t state)
 {
+	struct device *dev;
 	int error = 0;
 
-	while (!list_empty(&dpm_off)) {
-		struct list_head *entry = dpm_off.prev;
-		struct device *dev = to_device(entry);
-
-		error = suspend_device_late(dev, state);
+	list_for_each_entry_reverse(dev, &dpm_list, power.entry) {
+		error = suspend_device_noirq(dev, state);
 		if (error) {
 			printk(KERN_ERR "Could not power down device %s: "
 					"error %d\n",
 					kobject_name(&dev->kobj), error);
 			break;
 		}
-		if (!list_empty(&dev->power.entry))
-			list_move(&dev->power.entry, &dpm_off_irq);
+		dev->power.status = DPM_OFF_IRQ;
 	}
-
 	if (!error)
 		error = sysdev_suspend(state);
 	if (error)
-		dpm_power_up();
+		dpm_power_up(resume_event(state));
 	return error;
 }
 EXPORT_SYMBOL_GPL(device_power_down);
@@ -319,7 +622,7 @@ EXPORT_SYMBOL_GPL(device_power_down);
 /**
  *	suspend_device - Save state of one device.
  *	@dev:	Device.
- *	@state:	Power state device is entering.
+ *	@state: PM transition of the system being carried out.
  */
 static int suspend_device(struct device *dev, pm_message_t state)
 {
@@ -327,29 +630,43 @@ static int suspend_device(struct device 
 
 	down(&dev->sem);
 
-	if (dev->power.power_state.event) {
-		dev_dbg(dev, "PM: suspend %d-->%d\n",
-			dev->power.power_state.event, state.event);
-	}
-
-	if (dev->class && dev->class->suspend) {
-		suspend_device_dbg(dev, state, "class ");
-		error = dev->class->suspend(dev, state);
-		suspend_report_result(dev->class->suspend, error);
+	if (dev->class) {
+		if (dev->class->pm) {
+			pm_dev_dbg(dev, state, "class ");
+			error = pm_op(dev, dev->class->pm, state);
+		} else if (dev->class->suspend) {
+			pm_dev_dbg(dev, state, "legacy class ");
+			error = dev->class->suspend(dev, state);
+			suspend_report_result(dev->class->suspend, error);
+		}
+		if (error)
+			goto End;
 	}
 
-	if (!error && dev->type && dev->type->suspend) {
-		suspend_device_dbg(dev, state, "type ");
-		error = dev->type->suspend(dev, state);
-		suspend_report_result(dev->type->suspend, error);
+	if (dev->type) {
+		if (dev->type->pm) {
+			pm_dev_dbg(dev, state, "type ");
+			error = pm_op(dev, dev->type->pm, state);
+		} else if (dev->type->suspend) {
+			pm_dev_dbg(dev, state, "legacy type ");
+			error = dev->type->suspend(dev, state);
+			suspend_report_result(dev->type->suspend, error);
+		}
+		if (error)
+			goto End;
 	}
 
-	if (!error && dev->bus && dev->bus->suspend) {
-		suspend_device_dbg(dev, state, "");
-		error = dev->bus->suspend(dev, state);
-		suspend_report_result(dev->bus->suspend, error);
+	if (dev->bus) {
+		if (dev->bus->pm) {
+			pm_dev_dbg(dev, state, "");
+			error = pm_op(dev, &dev->bus->pm->base, state);
+		} else if (dev->bus->suspend) {
+			pm_dev_dbg(dev, state, "legacy ");
+			error = dev->bus->suspend(dev, state);
+			suspend_report_result(dev->bus->suspend, error);
+		}
 	}
-
+ End:
 	up(&dev->sem);
 
 	return error;
@@ -357,67 +674,142 @@ static int suspend_device(struct device 
 
 /**
  *	dpm_suspend - Suspend every device.
- *	@state:	Power state to put each device in.
+ *	@state: PM transition of the system being carried out.
  *
- *	Walk the dpm_locked list.  Suspend each device and move it
- *	to the dpm_off list.
- *
- *	(For historical reasons, if it returns -EAGAIN, that used to mean
- *	that the device would be called again with interrupts disabled.
- *	These days, we use the "suspend_late()" callback for that, so we
- *	print a warning and consider it an error).
+ *	Execute the appropriate "suspend" callbacks for all devices.
  */
 static int dpm_suspend(pm_message_t state)
 {
+	struct list_head list;
 	int error = 0;
 
+	INIT_LIST_HEAD(&list);
 	mutex_lock(&dpm_list_mtx);
-	while (!list_empty(&dpm_active)) {
-		struct list_head *entry = dpm_active.prev;
-		struct device *dev = to_device(entry);
-
-		WARN_ON(dev->parent && dev->parent->power.sleeping);
+	while (!list_empty(&dpm_list)) {
+		struct device *dev = to_device(dpm_list.prev);
 
-		dev->power.sleeping = true;
+		get_device(dev);
 		mutex_unlock(&dpm_list_mtx);
+
 		error = suspend_device(dev, state);
+
 		mutex_lock(&dpm_list_mtx);
 		if (error) {
 			printk(KERN_ERR "Could not suspend device %s: "
-					"error %d%s\n",
-					kobject_name(&dev->kobj),
-					error,
-					(error == -EAGAIN ?
-					" (please convert to suspend_late)" :
-					""));
-			dev->power.sleeping = false;
+				"error %d\n", kobject_name(&dev->kobj), error);
+			put_device(dev);
 			break;
 		}
+		dev->power.status = DPM_OFF;
 		if (!list_empty(&dev->power.entry))
-			list_move(&dev->power.entry, &dpm_off);
+			list_move(&dev->power.entry, &list);
+		put_device(dev);
 	}
-	if (!error)
-		all_sleeping = true;
+	list_splice(&list, dpm_list.prev);
 	mutex_unlock(&dpm_list_mtx);
+	return error;
+}
+
+/**
+ *	prepare_device - Execute the ->prepare() callback(s) for given device.
+ *	@dev:	Device.
+ *	@state: PM transition of the system being carried out.
+ */
+static int prepare_device(struct device *dev, pm_message_t state)
+{
+	int error = 0;
+
+	down(&dev->sem);
+
+	if (dev->bus && dev->bus->pm && dev->bus->pm->base.prepare) {
+		pm_dev_dbg(dev, state, "preparing ");
+		error = dev->bus->pm->base.prepare(dev);
+		suspend_report_result(dev->bus->pm->base.prepare, error);
+		if (error)
+			goto End;
+	}
+
+	if (dev->type && dev->type->pm && dev->type->pm->prepare) {
+		pm_dev_dbg(dev, state, "preparing type ");
+		error = dev->type->pm->prepare(dev);
+		suspend_report_result(dev->type->pm->prepare, error);
+		if (error)
+			goto End;
+	}
+
+	if (dev->class && dev->class->pm && dev->class->pm->prepare) {
+		pm_dev_dbg(dev, state, "preparing class ");
+		error = dev->class->pm->prepare(dev);
+		suspend_report_result(dev->class->pm->prepare, error);
+	}
+ End:
+	up(&dev->sem);
+
+	return error;
+}
 
+/**
+ *	dpm_prepare - Prepare all devices for a PM transition.
+ *	@state: PM transition of the system being carried out.
+ *
+ *	Execute the ->prepare() callback for all devices.
+ */
+static int dpm_prepare(pm_message_t state)
+{
+	struct list_head list;
+	int error = 0;
+
+	INIT_LIST_HEAD(&list);
+	mutex_lock(&dpm_list_mtx);
+	transition_started = true;
+	while (!list_empty(&dpm_list)) {
+		struct device *dev = to_device(dpm_list.next);
+
+		get_device(dev);
+		dev->power.status = DPM_PREPARING;
+		mutex_unlock(&dpm_list_mtx);
+
+		error = prepare_device(dev, state);
+
+		mutex_lock(&dpm_list_mtx);
+		if (error) {
+			dev->power.status = DPM_ON;
+			if (error == -EAGAIN) {
+				put_device(dev);
+				continue;
+			}
+			printk(KERN_ERR "Could not prepare device %s "
+				"for suspend: error %d\n",
+				kobject_name(&dev->kobj), error);
+			put_device(dev);
+			break;
+		}
+		dev->power.status = DPM_SUSPENDING;
+		if (!list_empty(&dev->power.entry))
+			list_move_tail(&dev->power.entry, &list);
+		put_device(dev);
+	}
+	list_splice(&list, &dpm_list);
+	mutex_unlock(&dpm_list_mtx);
 	return error;
 }
 
 /**
  *	device_suspend - Save state and stop all devices in system.
- *	@state: new power management state
+ *	@state: PM transition of the system being carried out.
  *
- *	Prevent new devices from being registered, then lock all devices
- *	and suspend them.
+ *	Prepare and suspend all devices.
  */
 int device_suspend(pm_message_t state)
 {
 	int error;
 
 	might_sleep();
-	error = dpm_suspend(state);
+	error = dpm_prepare(state);
+	if (!error)
+		error = dpm_suspend(state);
 	if (error)
-		device_resume();
+		device_resume(resume_event(state));
 	return error;
 }
 EXPORT_SYMBOL_GPL(device_suspend);
Index: linux-2.6/include/linux/device.h
===================================================================
--- linux-2.6.orig/include/linux/device.h
+++ linux-2.6/include/linux/device.h
@@ -69,6 +69,8 @@ struct bus_type {
 	int (*resume_early)(struct device *dev);
 	int (*resume)(struct device *dev);
 
+	struct pm_ext_ops *pm;
+
 	struct bus_type_private *p;
 };
 
@@ -132,6 +134,8 @@ struct device_driver {
 	int (*resume) (struct device *dev);
 	struct attribute_group **groups;
 
+	struct pm_ops *pm;
+
 	struct driver_private *p;
 };
 
@@ -202,6 +206,8 @@ struct class {
 
 	int (*suspend)(struct device *dev, pm_message_t state);
 	int (*resume)(struct device *dev);
+
+	struct pm_ops *pm;
 };
 
 extern int __must_check class_register(struct class *class);
@@ -345,8 +351,11 @@ struct device_type {
 	struct attribute_group **groups;
 	int (*uevent)(struct device *dev, struct kobj_uevent_env *env);
 	void (*release)(struct device *dev);
+
 	int (*suspend)(struct device *dev, pm_message_t state);
 	int (*resume)(struct device *dev);
+
+	struct pm_ops *pm;
 };
 
 /* interface for exporting device attributes */
Index: linux-2.6/kernel/power/disk.c
===================================================================
--- linux-2.6.orig/kernel/power/disk.c
+++ linux-2.6/kernel/power/disk.c
@@ -193,6 +193,7 @@ static int create_image(int platform_mod
 	if (error)
 		return error;
 
+	device_pm_lock();
 	local_irq_disable();
 	/* At this point, device_suspend() has been called, but *not*
 	 * device_power_down(). We *must* call device_power_down() now.
@@ -224,9 +225,10 @@ static int create_image(int platform_mod
 	/* NOTE:  device_power_up() is just a resume() for devices
 	 * that suspended with irqs off ... no overall powerup.
 	 */
-	device_power_up();
+	device_power_up(in_suspend ? PMSG_RECOVER : PMSG_RESTORE);
  Enable_irqs:
 	local_irq_enable();
+	device_pm_unlock();
 	return error;
 }
 
@@ -280,7 +282,7 @@ int hibernation_snapshot(int platform_mo
  Finish:
 	platform_finish(platform_mode);
  Resume_devices:
-	device_resume();
+	device_resume(in_suspend ? PMSG_RECOVER : PMSG_RESTORE);
  Resume_console:
 	resume_console();
  Close:
@@ -300,8 +302,9 @@ static int resume_target_kernel(void)
 {
 	int error;
 
+	device_pm_lock();
 	local_irq_disable();
-	error = device_power_down(PMSG_PRETHAW);
+	error = device_power_down(PMSG_QUIESCE);
 	if (error) {
 		printk(KERN_ERR "PM: Some devices failed to power down, "
 			"aborting resume\n");
@@ -329,9 +332,10 @@ static int resume_target_kernel(void)
 	swsusp_free();
 	restore_processor_state();
 	touch_softlockup_watchdog();
-	device_power_up();
+	device_power_up(PMSG_THAW);
  Enable_irqs:
 	local_irq_enable();
+	device_pm_unlock();
 	return error;
 }
 
@@ -350,7 +354,7 @@ int hibernation_restore(int platform_mod
 
 	pm_prepare_console();
 	suspend_console();
-	error = device_suspend(PMSG_PRETHAW);
+	error = device_suspend(PMSG_QUIESCE);
 	if (error)
 		goto Finish;
 
@@ -362,7 +366,7 @@ int hibernation_restore(int platform_mod
 		enable_nonboot_cpus();
 	}
 	platform_restore_cleanup(platform_mode);
-	device_resume();
+	device_resume(PMSG_RECOVER);
  Finish:
 	resume_console();
 	pm_restore_console();
@@ -403,6 +407,7 @@ int hibernation_platform_enter(void)
 	if (error)
 		goto Finish;
 
+	device_pm_lock();
 	local_irq_disable();
 	error = device_power_down(PMSG_HIBERNATE);
 	if (!error) {
@@ -411,6 +416,7 @@ int hibernation_platform_enter(void)
 		while (1);
 	}
 	local_irq_enable();
+	device_pm_unlock();
 
 	/*
 	 * We don't need to reenable the nonboot CPUs or resume consoles, since
@@ -419,7 +425,7 @@ int hibernation_platform_enter(void)
  Finish:
 	hibernation_ops->finish();
  Resume_devices:
-	device_resume();
+	device_resume(PMSG_RESTORE);
  Resume_console:
 	resume_console();
  Close:
Index: linux-2.6/kernel/power/main.c
===================================================================
--- linux-2.6.orig/kernel/power/main.c
+++ linux-2.6/kernel/power/main.c
@@ -228,6 +228,7 @@ static int suspend_enter(suspend_state_t
 {
 	int error = 0;
 
+	device_pm_lock();
 	arch_suspend_disable_irqs();
 	BUG_ON(!irqs_disabled());
 
@@ -239,10 +240,11 @@ static int suspend_enter(suspend_state_t
 	if (!suspend_test(TEST_CORE))
 		error = suspend_ops->enter(state);
 
-	device_power_up();
+	device_power_up(PMSG_RESUME);
  Done:
 	arch_suspend_enable_irqs();
 	BUG_ON(irqs_disabled());
+	device_pm_unlock();
 	return error;
 }
 
@@ -291,7 +293,7 @@ int suspend_devices_and_enter(suspend_st
 	if (suspend_ops->finish)
 		suspend_ops->finish();
  Resume_devices:
-	device_resume();
+	device_resume(PMSG_RESUME);
  Resume_console:
 	resume_console();
  Close:
Index: linux-2.6/arch/x86/kernel/apm_32.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/apm_32.c
+++ linux-2.6/arch/x86/kernel/apm_32.c
@@ -1208,9 +1208,9 @@ static int suspend(int vetoable)
 	if (err != APM_SUCCESS)
 		apm_error("suspend", err);
 	err = (err == APM_SUCCESS) ? 0 : -EIO;
-	device_power_up();
+	device_power_up(PMSG_RESUME);
 	local_irq_enable();
-	device_resume();
+	device_resume(PMSG_RESUME);
 	queue_event(APM_NORMAL_RESUME, NULL);
  out:
 	spin_lock(&user_list_lock);
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
@@ -4,7 +4,7 @@
  * main.c
  */
 
-extern struct list_head dpm_active;	/* The active device list */
+extern struct list_head dpm_list;	/* The active device list */
 
 static inline struct device *to_device(struct list_head *entry)
 {
Index: linux-2.6/drivers/base/power/trace.c
===================================================================
--- linux-2.6.orig/drivers/base/power/trace.c
+++ linux-2.6/drivers/base/power/trace.c
@@ -188,9 +188,9 @@ static int show_file_hash(unsigned int v
 static int show_dev_hash(unsigned int value)
 {
 	int match = 0;
-	struct list_head * entry = dpm_active.prev;
+	struct list_head *entry = dpm_list.prev;
 
-	while (entry != &dpm_active) {
+	while (entry != &dpm_list) {
 		struct device * dev = to_device(entry);
 		unsigned int hash = hash_string(DEVSEED, dev->bus_id, DEVHASH);
 		if (hash == value) {

Re: [RFC][PATCH] PM: Introduce new top level suspend and hibernation callbacks (rev. 6)

[Nigel Cunningham]

Hi Rafael.

Please excuse me, but I'm going to ask the questions you get from
someone who hasn't followed development to date, and is thus reading the
explanation without prior knowledge. Hopefully that will be helpful when
you come to finalising the commit message.

On Mon, 2008-03-31 at 23:29 +0200, Rafael J. Wysocki wrote:
> From: Rafael J. Wysocki <rjw@sisk.pl>
> 
> Introduce 'struct pm_ops' and 'struct pm_ext_ops' representing
> suspend and hibernation operations for bus types, device classes and
> device types.

Does ..._ext_... mean extended? (external?) If 'extended' (or if not),
does that imply that they're mutually exclusive alternatives for drivers
to use?

> Modify the PM core to use 'struct pm_ops' and 'struct pm_ext_ops'
> objects, if defined, instead of the ->suspend() and ->resume() or,
> respectively, ->suspend_late() and ->resume_early() callbacks that
> will be considered as legacy and gradually phased out.

'Respectively' doesn't look like the right word to use, but I'm not sure
I understand correctly what you're trying to say. The way it's written
at the moment, it sounds to me like you're saying that suspend_late()
and resume_early are deprecated, but you're modifying the PM core to use
them.

> Change the behavior of the PM core wrt the error codes returned by
> device drivers' ->resume() callbacks.  Namely, if an error code
> is returned by one of them, the device for which it's been returned
> is regarded as "invalid" by the PM core which will refuse to handle
> it from that point on (in particualr, suspend/hibernation will not
> be started if there is an "invalid" device in the system).

s/particualr,/particular

So drivers can never validly fail to resume. That sounds fair enough. If
the hardware has gone away while in lower power mode (USB, say), should
the driver then just printk an error and return success?

> The main purpose of doing this is to separate suspend (aka S2RAM and
> standby) callbacks from hibernation callbacks in such a way that the
> new callbacks won't take arguments and the semantics of each of them
> will be clearly specified.  This has been requested for multiple
> times by many people, including Linus himself, and the reason is that
> within the current scheme if ->resume() is called, for example, it's
> difficult to say why it's been called (ie. is it a resume from RAM or
> from hibernation or a suspend/hibernation failure etc.?).
> 
> The second purpose is to make the suspend/hibernation callbacks more
> flexible so that device drivers can handle more than they can within
> the current scheme.  For example, some drivers may need to prevent
> new children of the device from being registered before their
> ->suspend() callbacks are executed or they may want to carry out some
> operations requiring the availability of some other devices, not
> directly bound via the parent-child relationship, in order to prepare
> for the execution of ->suspend(), etc.

Do these changes allow for other power state possibilities besides
suspend to ram and hibernate (eg on other platforms)?

> Ultimately, we'd like to stop using the freezing of tasks for suspend
> and therefore the drivers' suspend/hibernation code will have to take
> care of the handling of the user space during suspend/hibernation.
> That, in turn, would be difficult within the current scheme, without
> the new ->prepare() and ->complete() callbacks.
> 
> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
> ---
> 
>  arch/x86/kernel/apm_32.c   |    4 
>  drivers/base/power/main.c  |  706 ++++++++++++++++++++++++++++++++++-----------
>  drivers/base/power/power.h |    2 
>  drivers/base/power/trace.c |    4 
>  include/linux/device.h     |    9 
>  include/linux/pm.h         |  318 ++++++++++++++++++--
>  kernel/power/disk.c        |   20 -
>  kernel/power/main.c        |    6 
>  8 files changed, 870 insertions(+), 199 deletions(-)
> 
> Index: linux-2.6/include/linux/pm.h
> ===================================================================
> --- linux-2.6.orig/include/linux/pm.h
> +++ linux-2.6/include/linux/pm.h
> @@ -114,7 +114,9 @@ typedef struct pm_message {
>  	int event;
>  } pm_message_t;
>  
> -/*
> +/**
> + * struct pm_ops - device PM callbacks
> + *
>   * Several driver power state transitions are externally visible, affecting
>   * the state of pending I/O queues and (for drivers that touch hardware)
>   * interrupts, wakeups, DMA, and other hardware state.  There may also be
> @@ -122,6 +124,288 @@ typedef struct pm_message {
>   * to the rest of the driver stack (such as a driver that's ON gating off
>   * clocks which are not in active use).
>   *
> + * The externally visible transitions are handled with the help of the following
> + * callbacks included in this structure:
> + *
> + * @prepare: Prepare the device for the upcoming transition, but do NOT change
> + *	its hardware state.  Prevent new children of the device from being
> + *	registered after @prepare() returns (the driver's subsystem and
> + *	generally the rest of the kernel is supposed to prevent new calls to the
> + *	probe method from being made too once @prepare() has succeeded).  If
> + *	@prepare() detects a situation it cannot handle (e.g. registration of a
> + *	child already in progress), it may return -EAGAIN, so that the PM core
> + *	can execute it once again (e.g. after the new child has 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 @prepare() for all devices before starting to
> + *	execute suspend callbacks for any of them, so drivers may assume all of
> + *	the other devices to be present and functional while @prepare() is being
> + *	executed.  In particular, it is safe to make GFP_KERNEL memory
> + *	allocations from within @prepare(), although they are likely to fail in
> + *	case of hibernation, if a substantial amount of memory is requested.

Why?

> + *	However, drivers may NOT assume anything about the availability of the
> + *	user space at that time and it is not correct to request firmware from
> + *	within @prepare() (it's too late to do that).

That doesn't sound good. It would be good to be able to get drivers to
request firmware early in the process.

> + * @complete: Undo the changes made by @prepare().  This method is executed for
> + *	all kinds of resume transitions, following one of the resume callbacks:
> + *	@resume(), @thaw(), @restore().  Also called if the state transition
> + *	fails before the driver's suspend callback (@suspend(), @freeze(),
> + *	@poweroff()) can be executed (e.g. if the suspend callback fails for one
> + *	of the other devices that the PM core has unsucessfully attempted to

s/unsucessfully/unsuccessfully

Regards,

Nigel


_______________________________________________
linux-pm mailing list
linux-pm@lists.linux-foundation.org
https://lists.linux-foundation.org/mailman/listinfo/linux-pm

Re: [RFC][PATCH] PM: Introduce new top level suspend and hibernation callbacks (rev. 6)

[Benjamin Herrenschmidt]

On Tue, 2008-04-01 at 19:15 +1100, Nigel Cunningham wrote:
> > + *   However, drivers may NOT assume anything about the availability of the
> > + *   user space at that time and it is not correct to request firmware from
> > + *   within @prepare() (it's too late to do that).
> 
> That doesn't sound good. It would be good to be able to get drivers to
> request firmware early in the process.

Agreed. Prepare() should still allow request_firmware and full userspace
communication / helper usage.

> > + * @complete: Undo the changes made by @prepare().  This method is executed for
> > + *   all kinds of resume transitions, following one of the resume callbacks:
> > + *   @resume(), @thaw(), @restore().  Also called if the state transition
> > + *   fails before the driver's suspend callback (@suspend(), @freeze(),
> > + *   @poweroff()) can be executed (e.g. if the suspend callback fails for one
> > + *   of the other devices that the PM core has unsucessfully attempted to

Ben.

Re: [RFC][PATCH] PM: Introduce new top level suspend and hibernation callbacks (rev. 6)

[Alan Stern]

On Tue, 1 Apr 2008, Benjamin Herrenschmidt wrote:

> On Tue, 2008-04-01 at 19:15 +1100, Nigel Cunningham wrote:
> > > + *   However, drivers may NOT assume anything about the availability of the
> > > + *   user space at that time and it is not correct to request firmware from
> > > + *   within @prepare() (it's too late to do that).
> > 
> > That doesn't sound good. It would be good to be able to get drivers to
> > request firmware early in the process.
> 
> Agreed. Prepare() should still allow request_firmware and full userspace
> communication / helper usage.

Pepare() is called after userspace has been frozen.  (Of course, once 
the freezer goes away this won't matter any more.)

There is a separate notifier chain which drivers can subscribe to;
notifications about impending sleeps are sent out while userspace is
still alive.  Drivers can use that for request_firmware, memory
allocation, and other things.

Alan Stern

Re: [RFC][PATCH] PM: Introduce new top level suspend and hibernation callbacks (rev. 6)

[Rafael J. Wysocki]

On Tuesday, 1 of April 2008, Benjamin Herrenschmidt wrote:
> 
> On Tue, 2008-04-01 at 19:15 +1100, Nigel Cunningham wrote:
> > > + *   However, drivers may NOT assume anything about the availability of the
> > > + *   user space at that time and it is not correct to request firmware from
> > > + *   within @prepare() (it's too late to do that).
> > 
> > That doesn't sound good. It would be good to be able to get drivers to
> > request firmware early in the process.
> 
> Agreed. Prepare() should still allow request_firmware and full userspace
> communication / helper usage.

This documents the current state which is that we have the freezer and we have
drivers that rely on it.

I can remove the comment, but then someone will invent ->prepare() relying
on the availability of the user space at this point and that won't work.

Thanks,
Rafael

Re: [RFC][PATCH] PM: Introduce new top level suspend and hibernation callbacks (rev. 6)

[Rafael J. Wysocki]

On Tuesday, 1 of April 2008, Nigel Cunningham wrote:
> Hi Rafael.

Hi,

> Please excuse me, but I'm going to ask the questions you get from
> someone who hasn't followed development to date, and is thus reading the
> explanation without prior knowledge. Hopefully that will be helpful when
> you come to finalising the commit message.
> 
> On Mon, 2008-03-31 at 23:29 +0200, Rafael J. Wysocki wrote:
> > From: Rafael J. Wysocki <rjw@sisk.pl>
> > 
> > Introduce 'struct pm_ops' and 'struct pm_ext_ops' representing
> > suspend and hibernation operations for bus types, device classes and
> > device types.
> 
> Does ..._ext_... mean extended? (external?) If 'extended' (or if not),
> does that imply that they're mutually exclusive alternatives for drivers
> to use?

'ext' means 'extended'.  The idea is that the 'extended' version will be used
by bus types / driver types that don't need to implement the _noirq callbacks.
Both the platform and PCI bus types generally allow drivers to use _noirq
callbacks, so they use 'struct pm_ext_ops', as well as their corresponding
driver types.

> > Modify the PM core to use 'struct pm_ops' and 'struct pm_ext_ops'
> > objects, if defined, instead of the ->suspend() and ->resume() or,
> > respectively, ->suspend_late() and ->resume_early() callbacks that
> > will be considered as legacy and gradually phased out.
> 
> 'Respectively' doesn't look like the right word to use, but I'm not sure
> I understand correctly what you're trying to say. The way it's written
> at the moment, it sounds to me like you're saying that suspend_late()
> and resume_early are deprecated, but you're modifying the PM core to use
> them.

Yes, the changelog is wrong, because I used a separate structure for the
_noirq callbacks and (quite blindly) change the name of the structure in the
changelog, instead of reworking it. 

> > Change the behavior of the PM core wrt the error codes returned by
> > device drivers' ->resume() callbacks.  Namely, if an error code
> > is returned by one of them, the device for which it's been returned
> > is regarded as "invalid" by the PM core which will refuse to handle
> > it from that point on (in particualr, suspend/hibernation will not
> > be started if there is an "invalid" device in the system).
> 
> s/particualr,/particular

Yes, thanks.
 
> So drivers can never validly fail to resume. That sounds fair enough. If
> the hardware has gone away while in lower power mode (USB, say), should
> the driver then just printk an error and return success?

I think so.

IMO, an error code returned by a driver's ->resume() should mean "the device
hasn't resumed and is presumably dead".  Otherwise, ->resume() should return
success.

> > The main purpose of doing this is to separate suspend (aka S2RAM and
> > standby) callbacks from hibernation callbacks in such a way that the
> > new callbacks won't take arguments and the semantics of each of them
> > will be clearly specified.  This has been requested for multiple
> > times by many people, including Linus himself, and the reason is that
> > within the current scheme if ->resume() is called, for example, it's
> > difficult to say why it's been called (ie. is it a resume from RAM or
> > from hibernation or a suspend/hibernation failure etc.?).
> > 
> > The second purpose is to make the suspend/hibernation callbacks more
> > flexible so that device drivers can handle more than they can within
> > the current scheme.  For example, some drivers may need to prevent
> > new children of the device from being registered before their
> > ->suspend() callbacks are executed or they may want to carry out some
> > operations requiring the availability of some other devices, not
> > directly bound via the parent-child relationship, in order to prepare
> > for the execution of ->suspend(), etc.
> 
> Do these changes allow for other power state possibilities besides
> suspend to ram and hibernate (eg on other platforms)?

The other states fall into the "suspend" category.

> > Ultimately, we'd like to stop using the freezing of tasks for suspend
> > and therefore the drivers' suspend/hibernation code will have to take
> > care of the handling of the user space during suspend/hibernation.
> > That, in turn, would be difficult within the current scheme, without
> > the new ->prepare() and ->complete() callbacks.
> > 
> > Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
> > ---
> > 
> >  arch/x86/kernel/apm_32.c   |    4 
> >  drivers/base/power/main.c  |  706 ++++++++++++++++++++++++++++++++++-----------
> >  drivers/base/power/power.h |    2 
> >  drivers/base/power/trace.c |    4 
> >  include/linux/device.h     |    9 
> >  include/linux/pm.h         |  318 ++++++++++++++++++--
> >  kernel/power/disk.c        |   20 -
> >  kernel/power/main.c        |    6 
> >  8 files changed, 870 insertions(+), 199 deletions(-)
> > 
> > Index: linux-2.6/include/linux/pm.h
> > ===================================================================
> > --- linux-2.6.orig/include/linux/pm.h
> > +++ linux-2.6/include/linux/pm.h
> > @@ -114,7 +114,9 @@ typedef struct pm_message {
> >  	int event;
> >  } pm_message_t;
> >  
> > -/*
> > +/**
> > + * struct pm_ops - device PM callbacks
> > + *
> >   * Several driver power state transitions are externally visible, affecting
> >   * the state of pending I/O queues and (for drivers that touch hardware)
> >   * interrupts, wakeups, DMA, and other hardware state.  There may also be
> > @@ -122,6 +124,288 @@ typedef struct pm_message {
> >   * to the rest of the driver stack (such as a driver that's ON gating off
> >   * clocks which are not in active use).
> >   *
> > + * The externally visible transitions are handled with the help of the following
> > + * callbacks included in this structure:
> > + *
> > + * @prepare: Prepare the device for the upcoming transition, but do NOT change
> > + *	its hardware state.  Prevent new children of the device from being
> > + *	registered after @prepare() returns (the driver's subsystem and
> > + *	generally the rest of the kernel is supposed to prevent new calls to the
> > + *	probe method from being made too once @prepare() has succeeded).  If
> > + *	@prepare() detects a situation it cannot handle (e.g. registration of a
> > + *	child already in progress), it may return -EAGAIN, so that the PM core
> > + *	can execute it once again (e.g. after the new child has 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 @prepare() for all devices before starting to
> > + *	execute suspend callbacks for any of them, so drivers may assume all of
> > + *	the other devices to be present and functional while @prepare() is being
> > + *	executed.  In particular, it is safe to make GFP_KERNEL memory
> > + *	allocations from within @prepare(), although they are likely to fail in
> > + *	case of hibernation, if a substantial amount of memory is requested.
> 
> Why?

Hmm, you're right.  This is the other way around - if a device allocates too
much RAM, we won't have enough memory to create the image.

> > + *	However, drivers may NOT assume anything about the availability of the
> > + *	user space at that time and it is not correct to request firmware from
> > + *	within @prepare() (it's too late to do that).
> 
> That doesn't sound good. It would be good to be able to get drivers to
> request firmware early in the process.

That will be possible when we drop the freezer.

> > + * @complete: Undo the changes made by @prepare().  This method is executed for
> > + *	all kinds of resume transitions, following one of the resume callbacks:
> > + *	@resume(), @thaw(), @restore().  Also called if the state transition
> > + *	fails before the driver's suspend callback (@suspend(), @freeze(),
> > + *	@poweroff()) can be executed (e.g. if the suspend callback fails for one
> > + *	of the other devices that the PM core has unsucessfully attempted to
> 
> s/unsucessfully/unsuccessfully

Thanks, will fix.

Rafael
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Re: [RFC][PATCH] PM: Introduce new top level suspend and hibernation callbacks (rev. 6)

[Alan Stern]

On Tue, 1 Apr 2008, Rafael J. Wysocki wrote:

> > Does ..._ext_... mean extended? (external?) If 'extended' (or if not),
> > does that imply that they're mutually exclusive alternatives for drivers
> > to use?
> 
> 'ext' means 'extended'.  The idea is that the 'extended' version will be used
> by bus types / driver types that don't need to implement the _noirq callbacks.

Something's wrong here.  This seems to say that the "extended" version
has _fewer_ method pointers -- in which case it should be called 
"restricted" instead.

> > So drivers can never validly fail to resume. That sounds fair enough. If
> > the hardware has gone away while in lower power mode (USB, say), should
> > the driver then just printk an error and return success?
> 
> I think so.
> 
> IMO, an error code returned by a driver's ->resume() should mean "the device
> hasn't resumed and is presumably dead".  Otherwise, ->resume() should return
> success.

If the device is gone, it doesn't much matter what resume() returns.

Alan Stern

Re: [RFC][PATCH] PM: Introduce new top level suspend and hibernation callbacks (rev. 6)

[Nigel Cunningham]

Hi Rafael etc.

On Tue, 2008-04-01 at 22:12 +0200, Rafael J. Wysocki wrote:
> 'ext' means 'extended'.  The idea is that the 'extended' version will be used
> by bus types / driver types that don't need to implement the _noirq callbacks.
> Both the platform and PCI bus types generally allow drivers to use _noirq
> callbacks, so they use 'struct pm_ext_ops', as well as their corresponding
> driver types.

Do you mean to say in the first sentence "...that _do_ need to
implement..."? If not, then extended sounds like a misnomer and the two
sentences seem to contradict one another.

[...]

> > > + *	However, drivers may NOT assume anything about the availability of the
> > > + *	user space at that time and it is not correct to request firmware from
> > > + *	within @prepare() (it's too late to do that).
> > 
> > That doesn't sound good. It would be good to be able to get drivers to
> > request firmware early in the process.
> 
> That will be possible when we drop the freezer.

Yeah, but right now, it seems to me to be a bogus limitation for drivers
to have no way of automatically loading firmware when you're about to
hibernate. (Of course I've since been reminded of the notifier chain -
that should probably be mentioned here as the way of achieving this).

By the way, I'm going to go on record now as saying I think dropping the
freezer is a silly idea. I'm therefore currently considering including
the freezer in TuxOnice from the time it gets dropped from mainline. I
know that will only make it less likely that TuxOnIce gets merged, but
I've given up caring about that anyway - caring about merging is
pointless when the people who decide if it gets merged don't care.

Regards,

Nigel

Re: [RFC][PATCH] PM: Introduce new top level suspend and hibernation callbacks (rev. 6)

[Rafael J. Wysocki]

On Tuesday, 1 of April 2008, Nigel Cunningham wrote:
> Hi Rafael etc.
> 
> On Tue, 2008-04-01 at 22:12 +0200, Rafael J. Wysocki wrote:
> > 'ext' means 'extended'.  The idea is that the 'extended' version will be used
> > by bus types / driver types that don't need to implement the _noirq callbacks.
> > Both the platform and PCI bus types generally allow drivers to use _noirq
> > callbacks, so they use 'struct pm_ext_ops', as well as their corresponding
> > driver types.
> 
> Do you mean to say in the first sentence "...that _do_ need to implement..."?

Yes, sorry.

> If not, then extended sounds like a misnomer and the two 
> sentences seem to contradict one another.
> 
> [...]
> 
> > > > + *	However, drivers may NOT assume anything about the availability of the
> > > > + *	user space at that time and it is not correct to request firmware from
> > > > + *	within @prepare() (it's too late to do that).
> > > 
> > > That doesn't sound good. It would be good to be able to get drivers to
> > > request firmware early in the process.
> > 
> > That will be possible when we drop the freezer.
> 
> Yeah, but right now, it seems to me to be a bogus limitation for drivers
> to have no way of automatically loading firmware when you're about to
> hibernate. (Of course I've since been reminded of the notifier chain -
> that should probably be mentioned here as the way of achieving this).

This is a tricky stuff, though, because the notifier is used for disabling the
user mode helpers too ...
 
> By the way, I'm going to go on record now as saying I think dropping the
> freezer is a silly idea. I'm therefore currently considering including
> the freezer in TuxOnice from the time it gets dropped from mainline. I
> know that will only make it less likely that TuxOnIce gets merged, but
> I've given up caring about that anyway - caring about merging is
> pointless when the people who decide if it gets merged don't care.

Well, I'm just not sure if dropping the freezer entirely will actually work,
but we won't know that if we don't try.

There's been a lot of pressure on going into this direction recently and
in principle it seems to be doable at least for suspend.  Hibernation is
another issue, but IMO it's better to focus on suspend first.

Thanks,
Rafael

Re: [RFC][PATCH] PM: Introduce new top level suspend and hibernation callbacks (rev. 6)

[Nigel Cunningham]

Hi.

On Tue, 2008-04-01 at 23:57 +0200, Rafael J. Wysocki wrote:
> On Tuesday, 1 of April 2008, Nigel Cunningham wrote:
> > Hi Rafael etc.
> > 
> > On Tue, 2008-04-01 at 22:12 +0200, Rafael J. Wysocki wrote:
> > > 'ext' means 'extended'.  The idea is that the 'extended' version will be used
> > > by bus types / driver types that don't need to implement the _noirq callbacks.
> > > Both the platform and PCI bus types generally allow drivers to use _noirq
> > > callbacks, so they use 'struct pm_ext_ops', as well as their corresponding
> > > driver types.
> > 
> > Do you mean to say in the first sentence "...that _do_ need to implement..."?
> 
> Yes, sorry.

Okay. Thanks!

> > If not, then extended sounds like a misnomer and the two 
> > sentences seem to contradict one another.
> > 
> > [...]
> > 
> > > > > + *	However, drivers may NOT assume anything about the availability of the
> > > > > + *	user space at that time and it is not correct to request firmware from
> > > > > + *	within @prepare() (it's too late to do that).
> > > > 
> > > > That doesn't sound good. It would be good to be able to get drivers to
> > > > request firmware early in the process.
> > > 
> > > That will be possible when we drop the freezer.
> > 
> > Yeah, but right now, it seems to me to be a bogus limitation for drivers
> > to have no way of automatically loading firmware when you're about to
> > hibernate. (Of course I've since been reminded of the notifier chain -
> > that should probably be mentioned here as the way of achieving this).
> 
> This is a tricky stuff, though, because the notifier is used for disabling the
> user mode helpers too ...

Hmm. Yet another notifier?
 
> > By the way, I'm going to go on record now as saying I think dropping the
> > freezer is a silly idea. I'm therefore currently considering including
> > the freezer in TuxOnice from the time it gets dropped from mainline. I
> > know that will only make it less likely that TuxOnIce gets merged, but
> > I've given up caring about that anyway - caring about merging is
> > pointless when the people who decide if it gets merged don't care.
> 
> Well, I'm just not sure if dropping the freezer entirely will actually work,
> but we won't know that if we don't try.
> 
> There's been a lot of pressure on going into this direction recently and
> in principle it seems to be doable at least for suspend.  Hibernation is
> another issue, but IMO it's better to focus on suspend first.

For suspend, I agree with dropping its use. For hibernation...

Nigel

Re: [RFC][PATCH] PM: Introduce new top level suspend and hibernation callbacks (rev. 6)

[Rafael J. Wysocki]

On Wednesday, 2 of April 2008, Nigel Cunningham wrote:
> Hi.
> 
> On Tue, 2008-04-01 at 23:57 +0200, Rafael J. Wysocki wrote:
> > On Tuesday, 1 of April 2008, Nigel Cunningham wrote:
> > > Hi Rafael etc.
> > > 
> > > On Tue, 2008-04-01 at 22:12 +0200, Rafael J. Wysocki wrote:
[--snip--]
> > > 
> > > > > > + *	However, drivers may NOT assume anything about the availability of the
> > > > > > + *	user space at that time and it is not correct to request firmware from
> > > > > > + *	within @prepare() (it's too late to do that).
> > > > > 
> > > > > That doesn't sound good. It would be good to be able to get drivers to
> > > > > request firmware early in the process.
> > > > 
> > > > That will be possible when we drop the freezer.
> > > 
> > > Yeah, but right now, it seems to me to be a bogus limitation for drivers
> > > to have no way of automatically loading firmware when you're about to
> > > hibernate. (Of course I've since been reminded of the notifier chain -
> > > that should probably be mentioned here as the way of achieving this).
> > 
> > This is a tricky stuff, though, because the notifier is used for disabling the
> > user mode helpers too ...
> 
> Hmm. Yet another notifier?

Well, perhaps it's better to disable user mode helpers directly from
freeze_processes().

Still, let's do one thing at a time. :-)

> > > By the way, I'm going to go on record now as saying I think dropping the
> > > freezer is a silly idea. I'm therefore currently considering including
> > > the freezer in TuxOnice from the time it gets dropped from mainline. I
> > > know that will only make it less likely that TuxOnIce gets merged, but
> > > I've given up caring about that anyway - caring about merging is
> > > pointless when the people who decide if it gets merged don't care.
> > 
> > Well, I'm just not sure if dropping the freezer entirely will actually work,
> > but we won't know that if we don't try.
> > 
> > There's been a lot of pressure on going into this direction recently and
> > in principle it seems to be doable at least for suspend.  Hibernation is
> > another issue, but IMO it's better to focus on suspend first.
> 
> For suspend, I agree with dropping its use. For hibernation...

I'm not sure and that's why I added the comment about the availability of
the user space during ->prepare().

Besides, for now, the freezer is necessary anyway, even for suspend.

Thanks,
Rafael

Re: [RFC][PATCH] PM: Introduce new top level suspend and hibernation callbacks (rev. 6)

[Pavel Machek]

> On Sunday, 30 of March 2008, Rafael J. Wysocki wrote:
> > On Saturday, 29 of March 2008, Rafael J. Wysocki wrote:
> > > From: Rafael J. Wysocki <rjw@sisk.pl>
> > > 
> > > Introduce 'struct pm_ops' and 'struct pm_ext_ops' representing
> > > suspend and hibernation operations for bus types, device classes and
> > > device types.
> > > 
> > > Modify the PM core to use 'struct pm_ops' and 'struct pm_ext_ops'
> > > objects, if defined, instead of the ->suspend() and ->resume() or,
> > > respectively, ->suspend_late() and ->resume_early() callbacks that
> > > will be considered as legacy and gradually phased out.
> > 
> > Unfortunately I forgot to set dev->power.status to DPM_PREPARING before
> > calling ->prepare(), as documented.  Also, dpm_prepare() could cleaned up
> > a bit.
> > 
> > Fixed patch follows.
> 
> My testing shows that some drivers tend to return error codes from their
> ->resume() callbacks, even though the devices in question appear to work
> correctly after the seemingly failing suspend.

The drivers should be fixed not to do that, no?

-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

Re: [RFC][PATCH] PM: Introduce new top level suspend and hibernation callbacks (rev. 6)

[Rafael J. Wysocki]

On Tuesday, 1 of April 2008, Pavel Machek wrote:
> > On Sunday, 30 of March 2008, Rafael J. Wysocki wrote:
> > > On Saturday, 29 of March 2008, Rafael J. Wysocki wrote:
> > > > From: Rafael J. Wysocki <rjw@sisk.pl>
> > > > 
> > > > Introduce 'struct pm_ops' and 'struct pm_ext_ops' representing
> > > > suspend and hibernation operations for bus types, device classes and
> > > > device types.
> > > > 
> > > > Modify the PM core to use 'struct pm_ops' and 'struct pm_ext_ops'
> > > > objects, if defined, instead of the ->suspend() and ->resume() or,
> > > > respectively, ->suspend_late() and ->resume_early() callbacks that
> > > > will be considered as legacy and gradually phased out.
> > > 
> > > Unfortunately I forgot to set dev->power.status to DPM_PREPARING before
> > > calling ->prepare(), as documented.  Also, dpm_prepare() could cleaned up
> > > a bit.
> > > 
> > > Fixed patch follows.
> > 
> > My testing shows that some drivers tend to return error codes from their
> > ->resume() callbacks, even though the devices in question appear to work
> > correctly after the seemingly failing suspend.
> 
> The drivers should be fixed not to do that, no?

The problem is we generally don't know which drivers do that.  I know a few,
but there probably are others.

So, the idea is to allow them to do that for some time, but log error messages
indicating which drivers they are.  These messages will then allow us to fix
the drivers and once they've been fixed, we can apply a (very simple) patch to
change the behavior of the core (this patch will be easy to revert if need be,
whereas I really wouldn't like to be forced to revert the $subject patch by
predictable regressions).

Thanks,
Rafael

Re: [RFC][PATCH 2/3] PM: New suspend and hibernation callbacks for platform bus type (rev. 3)

[Rafael J. Wysocki]

On Saturday, 29 of March 2008, Rafael J. Wysocki wrote:
> From: Rafael J. Wysocki <rjw@sisk.pl>
> 
> Implement new suspend and hibernation callbacks for the platform bus
> type.

I found a bug in this patch.  Namely, platform_legacy_suspend_late() was used
instead of platform_legacy_suspend() and vice versa in platform_pm_freeze() and
platform_pm_freeze_noirq().

Corrected patch follows.

Thanks,
Rafael

---
From: Rafael J. Wysocki <rjw@sisk.pl>

Implement new suspend and hibernation callbacks for the platform bus
type.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
---
 drivers/base/platform.c         |  296 ++++++++++++++++++++++++++++++++++++++--
 include/linux/platform_device.h |    1 
 2 files changed, 289 insertions(+), 8 deletions(-)

Index: linux-2.6/include/linux/platform_device.h
===================================================================
--- linux-2.6.orig/include/linux/platform_device.h
+++ linux-2.6/include/linux/platform_device.h
@@ -53,6 +53,7 @@ struct platform_driver {
 	int (*suspend_late)(struct platform_device *, pm_message_t state);
 	int (*resume_early)(struct platform_device *);
 	int (*resume)(struct platform_device *);
+	struct pm_ext_ops *pm;
 	struct device_driver driver;
 };
 
Index: linux-2.6/drivers/base/platform.c
===================================================================
--- linux-2.6.orig/drivers/base/platform.c
+++ linux-2.6/drivers/base/platform.c
@@ -453,6 +453,8 @@ int platform_driver_register(struct plat
 		drv->driver.suspend = platform_drv_suspend;
 	if (drv->resume)
 		drv->driver.resume = platform_drv_resume;
+	if (drv->pm)
+		drv->driver.pm = &drv->pm->base;
 	return driver_register(&drv->driver);
 }
 EXPORT_SYMBOL_GPL(platform_driver_register);
@@ -560,7 +562,9 @@ static int platform_match(struct device 
 	return (strncmp(pdev->name, drv->name, BUS_ID_SIZE) == 0);
 }
 
-static int platform_suspend(struct device *dev, pm_message_t mesg)
+#ifdef CONFIG_PM_SLEEP
+
+static int platform_legacy_suspend(struct device *dev, pm_message_t mesg)
 {
 	int ret = 0;
 
@@ -570,7 +574,7 @@ static int platform_suspend(struct devic
 	return ret;
 }
 
-static int platform_suspend_late(struct device *dev, pm_message_t mesg)
+static int platform_legacy_suspend_late(struct device *dev, pm_message_t mesg)
 {
 	struct platform_driver *drv = to_platform_driver(dev->driver);
 	struct platform_device *pdev;
@@ -583,7 +587,7 @@ static int platform_suspend_late(struct 
 	return ret;
 }
 
-static int platform_resume_early(struct device *dev)
+static int platform_legacy_resume_early(struct device *dev)
 {
 	struct platform_driver *drv = to_platform_driver(dev->driver);
 	struct platform_device *pdev;
@@ -596,7 +600,7 @@ static int platform_resume_early(struct 
 	return ret;
 }
 
-static int platform_resume(struct device *dev)
+static int platform_legacy_resume(struct device *dev)
 {
 	int ret = 0;
 
@@ -606,15 +610,291 @@ static int platform_resume(struct device
 	return ret;
 }
 
+static int platform_pm_prepare(struct device *dev)
+{
+	struct device_driver *drv = dev->driver;
+	int ret = 0;
+
+	if (drv && drv->pm && drv->pm->prepare)
+		ret = drv->pm->prepare(dev);
+
+	return ret;
+}
+
+static void platform_pm_complete(struct device *dev)
+{
+	struct device_driver *drv = dev->driver;
+
+	if (drv && drv->pm && drv->pm->complete)
+		drv->pm->complete(dev);
+}
+
+#ifdef CONFIG_SUSPEND
+
+static int platform_pm_suspend(struct device *dev)
+{
+	struct device_driver *drv = dev->driver;
+	int ret = 0;
+
+	if (drv && drv->pm) {
+		if (drv->pm->suspend)
+			ret = drv->pm->suspend(dev);
+	} else {
+		ret = platform_legacy_suspend(dev, PMSG_SUSPEND);
+	}
+
+	return ret;
+}
+
+static int platform_pm_suspend_noirq(struct device *dev)
+{
+	struct platform_driver *pdrv;
+	int ret = 0;
+
+	if (!dev->driver)
+		return 0;
+
+	pdrv = to_platform_driver(dev->driver);
+	if (pdrv->pm) {
+		if (pdrv->pm->suspend_noirq)
+			ret = pdrv->pm->suspend_noirq(dev);
+	} else {
+		ret = platform_legacy_suspend_late(dev, PMSG_SUSPEND);
+	}
+
+	return ret;
+}
+
+static int platform_pm_resume(struct device *dev)
+{
+	struct device_driver *drv = dev->driver;
+	int ret = 0;
+
+	if (drv && drv->pm) {
+		if (drv->pm->resume)
+			ret = drv->pm->resume(dev);
+	} else {
+		ret = platform_legacy_resume(dev);
+	}
+
+	return ret;
+}
+
+static int platform_pm_resume_noirq(struct device *dev)
+{
+	struct platform_driver *pdrv;
+	int ret = 0;
+
+	if (!dev->driver)
+		return 0;
+
+	pdrv = to_platform_driver(dev->driver);
+	if (pdrv->pm) {
+		if (pdrv->pm->resume_noirq)
+			ret = pdrv->pm->resume_noirq(dev);
+	} else {
+		ret = platform_legacy_resume_early(dev);
+	}
+
+	return ret;
+}
+
+#else /* !CONFIG_SUSPEND */
+
+#define platform_pm_suspend		NULL
+#define platform_pm_resume		NULL
+#define platform_pm_suspend_noirq	NULL
+#define platform_pm_resume_noirq	NULL
+
+#endif /* !CONFIG_SUSPEND */
+
+#ifdef CONFIG_HIBERNATION
+
+static int platform_pm_freeze(struct device *dev)
+{
+	struct device_driver *drv = dev->driver;
+	int ret = 0;
+
+	if (!drv)
+		return 0;
+
+	if (drv->pm) {
+		if (drv->pm->freeze)
+			ret = drv->pm->freeze(dev);
+	} else {
+		ret = platform_legacy_suspend(dev, PMSG_FREEZE);
+	}
+
+	return ret;
+}
+
+static int platform_pm_freeze_noirq(struct device *dev)
+{
+	struct platform_driver *pdrv;
+	int ret = 0;
+
+	if (!dev->driver)
+		return 0;
+
+	pdrv = to_platform_driver(dev->driver);
+	if (pdrv->pm) {
+		if (pdrv->pm->freeze_noirq)
+			ret = pdrv->pm->freeze_noirq(dev);
+	} else {
+		ret = platform_legacy_suspend_late(dev, PMSG_FREEZE);
+	}
+
+	return ret;
+}
+
+static int platform_pm_thaw(struct device *dev)
+{
+	struct device_driver *drv = dev->driver;
+	int ret = 0;
+
+	if (drv && drv->pm) {
+		if (drv->pm->thaw)
+			ret = drv->pm->thaw(dev);
+	} else {
+		ret = platform_legacy_resume(dev);
+	}
+
+	return ret;
+}
+
+static int platform_pm_thaw_noirq(struct device *dev)
+{
+	struct platform_driver *pdrv;
+	int ret = 0;
+
+	if (!dev->driver)
+		return 0;
+
+	pdrv = to_platform_driver(dev->driver);
+	if (pdrv->pm) {
+		if (pdrv->pm->thaw_noirq)
+			ret = pdrv->pm->thaw_noirq(dev);
+	} else {
+		ret = platform_legacy_resume_early(dev);
+	}
+
+	return ret;
+}
+
+static int platform_pm_poweroff(struct device *dev)
+{
+	struct device_driver *drv = dev->driver;
+	int ret = 0;
+
+	if (drv && drv->pm) {
+		if (drv->pm->poweroff)
+			ret = drv->pm->poweroff(dev);
+	} else {
+		ret = platform_legacy_suspend(dev, PMSG_HIBERNATE);
+	}
+
+	return ret;
+}
+
+static int platform_pm_poweroff_noirq(struct device *dev)
+{
+	struct platform_driver *pdrv;
+	int ret = 0;
+
+	if (!dev->driver)
+		return 0;
+
+	pdrv = to_platform_driver(dev->driver);
+	if (pdrv->pm) {
+		if (pdrv->pm->poweroff_noirq)
+			ret = pdrv->pm->poweroff_noirq(dev);
+	} else {
+		ret = platform_legacy_suspend_late(dev, PMSG_HIBERNATE);
+	}
+
+	return ret;
+}
+
+static int platform_pm_restore(struct device *dev)
+{
+	struct device_driver *drv = dev->driver;
+	int ret = 0;
+
+	if (drv && drv->pm) {
+		if (drv->pm->restore)
+			ret = drv->pm->restore(dev);
+	} else {
+		ret = platform_legacy_resume(dev);
+	}
+
+	return ret;
+}
+
+static int platform_pm_restore_noirq(struct device *dev)
+{
+	struct platform_driver *pdrv;
+	int ret = 0;
+
+	if (!dev->driver)
+		return 0;
+
+	pdrv = to_platform_driver(dev->driver);
+	if (pdrv->pm) {
+		if (pdrv->pm->restore_noirq)
+			ret = pdrv->pm->restore_noirq(dev);
+	} else {
+		ret = platform_legacy_resume_early(dev);
+	}
+
+	return ret;
+}
+
+#else /* !CONFIG_HIBERNATION */
+
+#define platform_pm_freeze		NULL
+#define platform_pm_thaw		NULL
+#define platform_pm_poweroff		NULL
+#define platform_pm_restore		NULL
+#define platform_pm_freeze_noirq	NULL
+#define platform_pm_thaw_noirq		NULL
+#define platform_pm_poweroff_noirq	NULL
+#define platform_pm_restore_noirq	NULL
+
+#endif /* !CONFIG_HIBERNATION */
+
+struct pm_ext_ops platform_pm_ops = {
+	.base = {
+		.prepare = platform_pm_prepare,
+		.complete = platform_pm_complete,
+		.suspend = platform_pm_suspend,
+		.resume = platform_pm_resume,
+		.freeze = platform_pm_freeze,
+		.thaw = platform_pm_thaw,
+		.poweroff = platform_pm_poweroff,
+		.restore = platform_pm_restore,
+	},
+	.suspend_noirq = platform_pm_suspend_noirq,
+	.resume_noirq = platform_pm_resume_noirq,
+	.freeze_noirq = platform_pm_freeze_noirq,
+	.thaw_noirq = platform_pm_thaw_noirq,
+	.poweroff_noirq = platform_pm_poweroff_noirq,
+	.restore_noirq = platform_pm_restore_noirq,
+};
+
+#define PLATFORM_PM_OPS_PTR	&platform_pm_ops
+
+#else /* !CONFIG_PM_SLEEP */
+
+#define PLATFORM_PM_OPS_PTR	NULL
+
+#endif /* !CONFIG_PM_SLEEP */
+
 struct bus_type platform_bus_type = {
 	.name		= "platform",
 	.dev_attrs	= platform_dev_attrs,
 	.match		= platform_match,
 	.uevent		= platform_uevent,
-	.suspend	= platform_suspend,
-	.suspend_late	= platform_suspend_late,
-	.resume_early	= platform_resume_early,
-	.resume		= platform_resume,
+	.pm		= PLATFORM_PM_OPS_PTR,
 };
 EXPORT_SYMBOL_GPL(platform_bus_type);
 

Re: [RFC][PATCH] PM: Introduce new top level suspend and hibernation callbacks (rev. 6)

[Nigel Cunningham]

Hi.

On Tue, 2008-04-01 at 10:31 -0400, Alan Stern wrote:
> On Tue, 1 Apr 2008, Benjamin Herrenschmidt wrote:
> 
> > On Tue, 2008-04-01 at 19:15 +1100, Nigel Cunningham wrote:
> > > > + *   However, drivers may NOT assume anything about the availability of the
> > > > + *   user space at that time and it is not correct to request firmware from
> > > > + *   within @prepare() (it's too late to do that).
> > > 
> > > That doesn't sound good. It would be good to be able to get drivers to
> > > request firmware early in the process.
> > 
> > Agreed. Prepare() should still allow request_firmware and full userspace
> > communication / helper usage.
> 
> Pepare() is called after userspace has been frozen.  (Of course, once 
> the freezer goes away this won't matter any more.)
> 
> There is a separate notifier chain which drivers can subscribe to;
> notifications about impending sleeps are sent out while userspace is
> still alive.  Drivers can use that for request_firmware, memory
> allocation, and other things.

Then that should be mentioned here so that drivers authors can know that
it is possible to request firmware, allocate memory and so on at a stage
when you can still rely on userspace being alive.

Regards,

Nigel

Re: [RFC][PATCH] PM: Introduce new top level suspend and hibernation callbacks (rev. 6)

[Nigel Cunningham]

Hi.

On Tue, 2008-04-01 at 16:56 -0400, Alan Stern wrote:
> On Tue, 1 Apr 2008, Rafael J. Wysocki wrote:
> 
> > > Does ..._ext_... mean extended? (external?) If 'extended' (or if not),
> > > does that imply that they're mutually exclusive alternatives for drivers
> > > to use?
> > 
> > 'ext' means 'extended'.  The idea is that the 'extended' version will be used
> > by bus types / driver types that don't need to implement the _noirq callbacks.
> 
> Something's wrong here.  This seems to say that the "extended" version
> has _fewer_ method pointers -- in which case it should be called 
> "restricted" instead.

Agreed.

> > > So drivers can never validly fail to resume. That sounds fair enough. If
> > > the hardware has gone away while in lower power mode (USB, say), should
> > > the driver then just printk an error and return success?
> > 
> > I think so.
> > 
> > IMO, an error code returned by a driver's ->resume() should mean "the device
> > hasn't resumed and is presumably dead".  Otherwise, ->resume() should return
> > success.
> 
> If the device is gone, it doesn't much matter what resume() returns.

What if the same driver is handling multiple instances and only some of
them fail to resume?

Regards,

Nigel

Re: [RFC][PATCH] PM: Introduce new top level suspend and hibernation callbacks (rev. 6)

[Rafael J. Wysocki]

On Tuesday, 1 of April 2008, Alan Stern wrote:
> On Tue, 1 Apr 2008, Rafael J. Wysocki wrote:
> 
> > > Does ..._ext_... mean extended? (external?) If 'extended' (or if not),
> > > does that imply that they're mutually exclusive alternatives for drivers
> > > to use?
> > 
> > 'ext' means 'extended'.  The idea is that the 'extended' version will be used
> > by bus types / driver types that don't need to implement the _noirq callbacks.
> 
> Something's wrong here.  This seems to say that the "extended" version
> has _fewer_ method pointers -- in which case it should be called 
> "restricted" instead.

No, it has more pointers.  Specifically, it is like

struct pm_ext_ops {
	struct pm_ops base;
	--additional pointers go here--
}
 
> > > So drivers can never validly fail to resume. That sounds fair enough. If
> > > the hardware has gone away while in lower power mode (USB, say), should
> > > the driver then just printk an error and return success?
> > 
> > I think so.
> > 
> > IMO, an error code returned by a driver's ->resume() should mean "the device
> > hasn't resumed and is presumably dead".  Otherwise, ->resume() should return
> > success.
> 
> If the device is gone, it doesn't much matter what resume() returns.

Yes, it does.  In that cases, the error code would tell the PM core not to attempt
to resume the device's children etc.  Otherwise, it's quite meaningless to the
PM core, because it really can mean anything and how's the PM core supposed
to handle _that_?

Either we decide that the error codes returned by ->resume() mean critical
errors or there's no point in returning error codes from ->resume() at all
(other than logging the errors by the core).

Well, that's getting confused.  I think I'll have to rework the patch not to
really handle the errors returned by ->resume() and friends, after all, but
I'll keep the reporting of them.

However, I'd like to add a recommendation that the _new_ "resume" callbacks
should only return errors in critical situations as the indication to the PM
core that something went _really_ wrong and the device in question is quite
surely unusable.

Thanks,
Rafael

Re: [RFC][PATCH] PM: Introduce new top level suspend and hibernation callbacks (rev. 6)

[Rafael J. Wysocki]

On Tuesday, 1 of April 2008, Nigel Cunningham wrote:
> Hi.
> 
> On Tue, 2008-04-01 at 16:56 -0400, Alan Stern wrote:
> > On Tue, 1 Apr 2008, Rafael J. Wysocki wrote:
> > 
> > > > Does ..._ext_... mean extended? (external?) If 'extended' (or if not),
> > > > does that imply that they're mutually exclusive alternatives for drivers
> > > > to use?
> > > 
> > > 'ext' means 'extended'.  The idea is that the 'extended' version will be used
> > > by bus types / driver types that don't need to implement the _noirq callbacks.
> > 
> > Something's wrong here.  This seems to say that the "extended" version
> > has _fewer_ method pointers -- in which case it should be called 
> > "restricted" instead.
> 
> Agreed.

This was a mistake explained in another message.  The "don't" should not be
present in the above sentence.

> > > > So drivers can never validly fail to resume. That sounds fair enough. If
> > > > the hardware has gone away while in lower power mode (USB, say), should
> > > > the driver then just printk an error and return success?
> > > 
> > > I think so.
> > > 
> > > IMO, an error code returned by a driver's ->resume() should mean "the device
> > > hasn't resumed and is presumably dead".  Otherwise, ->resume() should return
> > > success.
> > 
> > If the device is gone, it doesn't much matter what resume() returns.
> 
> What if the same driver is handling multiple instances and only some of
> them fail to resume?

->resume() will be called separately for each of them.

Thanks,
Rafael

Re: [RFC][PATCH] PM: Introduce new top level suspend and hibernation callbacks (rev. 6)

[Alan Stern]

On Tue, 1 Apr 2008, Rafael J. Wysocki wrote:

> > If the device is gone, it doesn't much matter what resume() returns.
> 
> Yes, it does.  In that cases, the error code would tell the PM core not to attempt
> to resume the device's children etc.

If the device is gone then so are its descendants, right?  So it 
doesn't matter whether the PM core tries to resume them.

>  Otherwise, it's quite meaningless to the
> PM core, because it really can mean anything and how's the PM core supposed
> to handle _that_?

Exactly.  This is the point I was trying to make a week or so ago.

> Either we decide that the error codes returned by ->resume() mean critical
> errors or there's no point in returning error codes from ->resume() at all
> (other than logging the errors by the core).
> 
> Well, that's getting confused.  I think I'll have to rework the patch not to
> really handle the errors returned by ->resume() and friends, after all, but
> I'll keep the reporting of them.
> 
> However, I'd like to add a recommendation that the _new_ "resume" callbacks
> should only return errors in critical situations as the indication to the PM
> core that something went _really_ wrong and the device in question is quite
> surely unusable.

Agreed.  The most important aspect is that drivers should _not_ return
an error if the device is working correctly.  We should fix the drivers 
which make this mistake.

Alan Stern

Re: [RFC][PATCH] PM: Introduce new top level suspend and hibernation callbacks (rev. 6)

[Oliver Neukum]

Am Mittwoch, 2. April 2008 16:11:14 schrieb Alan Stern:
> > However, I'd like to add a recommendation that the _new_ "resume" callbacks
> > should only return errors in critical situations as the indication to the PM
> > core that something went _really_ wrong and the device in question is quite
> > surely unusable.
> 
> Agreed.  The most important aspect is that drivers should _not_ return
> an error if the device is working correctly.  We should fix the drivers 
> which make this mistake.

We need to do something about devices that don't want to be resumed.
There's code like this:


static int usb_resume(struct device *dev)
{
	struct usb_device	*udev;

	if (!is_usb_device(dev))	/* Ignore PM for interfaces */
		return 0;
	udev = to_usb_device(dev);

	/* If udev->skip_sys_resume is set then udev was already suspended
	 * when the system suspend started, so we don't want to resume
	 * udev during this system wakeup.  However a reset-resume counts
	 * as a wakeup event, so allow a reset-resume to occur if remote
	 * wakeup is enabled. */
	if (udev->skip_sys_resume) {
		if (!(udev->reset_resume && udev->do_remote_wakeup))
			return -EHOSTUNREACH;
	}
	return usb_external_resume_device(udev);
}

Do we want to keep this in the subsystems?

	Regards
		Oliver

Re: [RFC][PATCH] PM: Introduce new top level suspend and hibernation callbacks (rev. 6)

[Alan Stern]

On Wed, 2 Apr 2008, Oliver Neukum wrote:

> We need to do something about devices that don't want to be resumed.
> There's code like this:
> 
> 
> static int usb_resume(struct device *dev)
> {
> 	struct usb_device	*udev;
> 
> 	if (!is_usb_device(dev))	/* Ignore PM for interfaces */
> 		return 0;
> 	udev = to_usb_device(dev);
> 
> 	/* If udev->skip_sys_resume is set then udev was already suspended
> 	 * when the system suspend started, so we don't want to resume
> 	 * udev during this system wakeup.  However a reset-resume counts
> 	 * as a wakeup event, so allow a reset-resume to occur if remote
> 	 * wakeup is enabled. */
> 	if (udev->skip_sys_resume) {
> 		if (!(udev->reset_resume && udev->do_remote_wakeup))
> 			return -EHOSTUNREACH;
> 	}
> 	return usb_external_resume_device(udev);
> }
> 
> Do we want to keep this in the subsystems?

Basically yes.  Subsystems and drivers are allowed to keep devices
suspended if they were suspended before the system went to sleep.  
Remember, the purpose of the resume method is to let drivers know that
the system is now awake, not to force them to put their devices into a
high-power state.

But under these circumstances we don't want to return an error code,
since nothing really went wrong in the method.  So the -EHOSTUNREACH
should be changed to 0.

Alan Stern

Re: [RFC][PATCH] PM: Introduce new top level suspend and hibernation callbacks (rev. 6)

[Oliver Neukum]

Am Mittwoch, 2. April 2008 17:13:11 schrieb Alan Stern:
> Basically yes.  Subsystems and drivers are allowed to keep devices
> suspended if they were suspended before the system went to sleep.  
> Remember, the purpose of the resume method is to let drivers know that
> the system is now awake, not to force them to put their devices into a
> high-power state.

Well, sometimes it is exactly that what we desire, eg. as a side effect
of lsusb. Should the callbacks have different semantics depending on
the reason you call them? And how should that information be transferred?

	Regards
		Oliver

Re: [RFC][PATCH] PM: Introduce new top level suspend and hibernation callbacks (rev. 6)

[Alan Stern]

On Wed, 2 Apr 2008, Oliver Neukum wrote:

> Am Mittwoch, 2. April 2008 17:13:11 schrieb Alan Stern:
> > Basically yes.  Subsystems and drivers are allowed to keep devices
> > suspended if they were suspended before the system went to sleep.  
> > Remember, the purpose of the resume method is to let drivers know that
> > the system is now awake, not to force them to put their devices into a
> > high-power state.
> 
> Well, sometimes it is exactly that what we desire, eg. as a side effect
> of lsusb. Should the callbacks have different semantics depending on
> the reason you call them? And how should that information be transferred?

Which callbacks are you referring to?  When lsusb opens a device and
does an autoresume, it does not call the same routine as the PM core
does when resuming from a system sleep.  lsusb ends up calling
usb_autoresume_device() whereas the PM core ends up calling
usb_resume(), which is the function you quoted earlier.

Alan Stern

Re: [RFC][PATCH] PM: Introduce new top level suspend and hibernation callbacks (rev. 6)

[Oliver Neukum]

Am Mittwoch, 2. April 2008 18:42:15 schrieb Alan Stern:
> On Wed, 2 Apr 2008, Oliver Neukum wrote:
> 
> > Am Mittwoch, 2. April 2008 17:13:11 schrieb Alan Stern:
> > > Basically yes.  Subsystems and drivers are allowed to keep devices
> > > suspended if they were suspended before the system went to sleep.  
> > > Remember, the purpose of the resume method is to let drivers know that
> > > the system is now awake, not to force them to put their devices into a
> > > high-power state.
> > 
> > Well, sometimes it is exactly that what we desire, eg. as a side effect
> > of lsusb. Should the callbacks have different semantics depending on
> > the reason you call them? And how should that information be transferred?
> 
> Which callbacks are you referring to?  When lsusb opens a device and
> does an autoresume, it does not call the same routine as the PM core
> does when resuming from a system sleep.  lsusb ends up calling
> usb_autoresume_device() whereas the PM core ends up calling
> usb_resume(), which is the function you quoted earlier.

But how is usb_autoresume_device() supposed to take to the driver?
Furthermore suppose the interface woken up is storage. This will have
to work across subsystem borders. Why not put it into generic code?

	Regards
		Oliver

Re: [RFC][PATCH] PM: Introduce new top level suspend and hibernation callbacks (rev. 6)

[Alan Stern]

On Wed, 2 Apr 2008, Oliver Neukum wrote:

> Am Mittwoch, 2. April 2008 18:42:15 schrieb Alan Stern:
> > On Wed, 2 Apr 2008, Oliver Neukum wrote:
> > 
> > > Am Mittwoch, 2. April 2008 17:13:11 schrieb Alan Stern:
> > > > Basically yes.  Subsystems and drivers are allowed to keep devices
> > > > suspended if they were suspended before the system went to sleep.  
> > > > Remember, the purpose of the resume method is to let drivers know that
> > > > the system is now awake, not to force them to put their devices into a
> > > > high-power state.
> > > 
> > > Well, sometimes it is exactly that what we desire, eg. as a side effect
> > > of lsusb. Should the callbacks have different semantics depending on
> > > the reason you call them? And how should that information be transferred?
> > 
> > Which callbacks are you referring to?  When lsusb opens a device and
> > does an autoresume, it does not call the same routine as the PM core
> > does when resuming from a system sleep.  lsusb ends up calling
> > usb_autoresume_device() whereas the PM core ends up calling
> > usb_resume(), which is the function you quoted earlier.
> 
> But how is usb_autoresume_device() supposed to take to the driver?
> Furthermore suppose the interface woken up is storage. This will have
> to work across subsystem borders. Why not put it into generic code?

I'm not sure exactly what you're asking.  However it's worth mentioning 
that once the dust from Rafael's changes settles down, I intend to 
submit a patch creating new PM_EVENT_* codes:

	PM_EVENT_USER_SUSPEND
	PM_EVENT_USER_RESUME
	PM_EVENT_REMOTE_WAKEUP
	PM_EVENT_AUTOSUSPEND
	PM_EVENT_AUTORESUME

(and the corresponding PMSG_* definitions).  The PM core will never use
the new codes, but subsystems like USB will be able to use them
internally.  Does that answer your question?

Alan Stern