Merge branch 'linus' into x86/step

1 files changed, 523 insertions, 152 deletions

diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c
index 45cc3d9eacb8..3250c5257b74 100644
--- a/drivers/base/power/main.c
+++ b/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
@@ -68,17 +75,25 @@ 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\n",
+        if (dev->parent) {
+                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, "all devices are sleeping\n");
+                        WARN_ON(true);
+                }
+        } 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
+                 */
                 WARN_ON(true);
         }
         error = dpm_sysfs_add(dev);
-        if (!error)
-                list_add_tail(&dev->power.entry, &dpm_active);
+        if (!error) {
+                dev->power.status = DPM_ON;
+                list_add_tail(&dev->power.entry, &dpm_list);
+        }
         mutex_unlock(&dpm_list_mtx);
         return error;
 }
@@ -100,73 +115,243 @@ void device_pm_remove(struct device *dev)
         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";
+        case PM_EVENT_RECOVER:
+                return "recover";
+        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" : "");
+}
+
+static void pm_dev_err(struct device *dev, pm_message_t state, char *info,
+                        int error)
+{
+        printk(KERN_ERR "PM: Device %s failed to %s%s: error %d\n",
+                kobject_name(&dev->kobj), pm_verb(state.event), info, error);
+}
+
 /*------------------------- 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_for_each_entry(dev, &dpm_list, power.entry)
+                if (dev->power.status > DPM_OFF) {
+                        int error;
 
-                list_move_tail(entry, &dpm_off);
-                resume_device_early(dev);
-        }
+                        dev->power.status = DPM_OFF;
+                        error = resume_device_noirq(dev, state);
+                        if (error)
+                                pm_dev_err(dev, state, " early", error);
+                }
 }
 
 /**
  *      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;
 
@@ -175,21 +360,40 @@ static int resume_device(struct device *dev)
 
         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);
@@ -198,78 +402,161 @@ static int resume_device(struct device *dev)
 
 /**
  *      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->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)
+                                pm_dev_err(dev, state, "", error);
+                } 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);
         }
@@ -278,37 +565,30 @@ static int suspend_device_late(struct device *dev, pm_message_t state)
 
 /**
  *      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);
+                        pm_dev_err(dev, state, " late", 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);
@@ -316,7 +596,7 @@ 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)
 {
@@ -324,24 +604,43 @@ static int suspend_device(struct device *dev, pm_message_t state)
 
         down(&dev->sem);
 
-        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;
@@ -349,67 +648,139 @@ static int suspend_device(struct device *dev, pm_message_t state)
 
 /**
  *      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;
+                        pm_dev_err(dev, state, "", 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 "PM: Failed to prepare device %s "
+                                "for power transition: 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);
-        if (error)
-                device_resume();
+        error = dpm_prepare(state);
+        if (!error)
+                error = dpm_suspend(state);
         return error;
 }
 EXPORT_SYMBOL_GPL(device_suspend);