drm/radeon/kms: init rdev->num_crtc at asic init
[safe/jmp/linux-2.6] / drivers / base / power / main.c
index 69b4ddb..a5142bd 100644 (file)
 #include <linux/kallsyms.h>
 #include <linux/mutex.h>
 #include <linux/pm.h>
+#include <linux/pm_runtime.h>
 #include <linux/resume-trace.h>
-#include <linux/rwsem.h>
 #include <linux/interrupt.h>
+#include <linux/sched.h>
 
 #include "../base.h"
 #include "power.h"
@@ -49,7 +50,17 @@ static DEFINE_MUTEX(dpm_list_mtx);
 static bool transition_started;
 
 /**
- *     device_pm_lock - lock the list of active devices used by the PM core
+ * device_pm_init - Initialize the PM-related part of a device object.
+ * @dev: Device object being initialized.
+ */
+void device_pm_init(struct device *dev)
+{
+       dev->power.status = DPM_ON;
+       pm_runtime_init(dev);
+}
+
+/**
+ * device_pm_lock - Lock the list of active devices used by the PM core.
  */
 void device_pm_lock(void)
 {
@@ -57,7 +68,7 @@ void device_pm_lock(void)
 }
 
 /**
- *     device_pm_unlock - unlock the list of active devices used by the PM core
+ * device_pm_unlock - Unlock the list of active devices used by the PM core.
  */
 void device_pm_unlock(void)
 {
@@ -65,8 +76,8 @@ void device_pm_unlock(void)
 }
 
 /**
- *     device_pm_add - add a device to the list of active devices
- *     @dev:   Device to be added to the list
+ * device_pm_add - Add a device to the PM core's list of active devices.
+ * @dev: Device to add to the list.
  */
 void device_pm_add(struct device *dev)
 {
@@ -92,10 +103,8 @@ void device_pm_add(struct device *dev)
 }
 
 /**
- *     device_pm_remove - remove a device from the list of active devices
- *     @dev:   Device to be removed from the list
- *
- *     This function also removes the device's PM-related sysfs attributes.
+ * device_pm_remove - Remove a device from the PM core's list of active devices.
+ * @dev: Device to be removed from the list.
  */
 void device_pm_remove(struct device *dev)
 {
@@ -105,12 +114,13 @@ void device_pm_remove(struct device *dev)
        mutex_lock(&dpm_list_mtx);
        list_del_init(&dev->power.entry);
        mutex_unlock(&dpm_list_mtx);
+       pm_runtime_remove(dev);
 }
 
 /**
- *     device_pm_move_before - move device in dpm_list
- *     @deva:  Device to move in dpm_list
- *     @devb:  Device @deva should come before
+ * device_pm_move_before - Move device in the PM core's list of active devices.
+ * @deva: Device to move in dpm_list.
+ * @devb: Device @deva should come before.
  */
 void device_pm_move_before(struct device *deva, struct device *devb)
 {
@@ -124,9 +134,9 @@ void device_pm_move_before(struct device *deva, struct device *devb)
 }
 
 /**
- *     device_pm_move_after - move device in dpm_list
- *     @deva:  Device to move in dpm_list
- *     @devb:  Device @deva should come after
+ * device_pm_move_after - Move device in the PM core's list of active devices.
+ * @deva: Device to move in dpm_list.
+ * @devb: Device @deva should come after.
  */
 void device_pm_move_after(struct device *deva, struct device *devb)
 {
@@ -140,8 +150,8 @@ void device_pm_move_after(struct device *deva, struct device *devb)
 }
 
 /**
- *     device_pm_move_last - move device to end of dpm_list
- *     @dev:   Device to move in dpm_list
+ * device_pm_move_last - Move device to end of the PM core's list of devices.
+ * @dev: Device to move in dpm_list.
  */
 void device_pm_move_last(struct device *dev)
 {
@@ -151,16 +161,46 @@ void device_pm_move_last(struct device *dev)
        list_move_tail(&dev->power.entry, &dpm_list);
 }
 
+static ktime_t initcall_debug_start(struct device *dev)
+{
+       ktime_t calltime = ktime_set(0, 0);
+
+       if (initcall_debug) {
+               pr_info("calling  %s+ @ %i\n",
+                               dev_name(dev), task_pid_nr(current));
+               calltime = ktime_get();
+       }
+
+       return calltime;
+}
+
+static void initcall_debug_report(struct device *dev, ktime_t calltime,
+                                 int error)
+{
+       ktime_t delta, rettime;
+
+       if (initcall_debug) {
+               rettime = ktime_get();
+               delta = ktime_sub(rettime, calltime);
+               pr_info("call %s+ returned %d after %Ld usecs\n", dev_name(dev),
+                       error, (unsigned long long)ktime_to_ns(delta) >> 10);
+       }
+}
+
 /**
- *     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.
+ * pm_op - Execute the PM operation appropriate for given PM event.
+ * @dev: Device to handle.
+ * @ops: PM operations to choose from.
+ * @state: PM transition of the system being carried out.
  */
-static int pm_op(struct device *dev, struct dev_pm_ops *ops,
-                       pm_message_t state)
+static int pm_op(struct device *dev,
+                const struct dev_pm_ops *ops,
+                pm_message_t state)
 {
        int error = 0;
+       ktime_t calltime;
+
+       calltime = initcall_debug_start(dev);
 
        switch (state.event) {
 #ifdef CONFIG_SUSPEND
@@ -208,22 +248,33 @@ static int pm_op(struct device *dev, struct dev_pm_ops *ops,
        default:
                error = -EINVAL;
        }
+
+       initcall_debug_report(dev, calltime, error);
+
        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.
+ * pm_noirq_op - Execute the PM operation appropriate for given PM event.
+ * @dev: Device to handle.
+ * @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.
+ * The driver of @dev will not receive interrupts while this function is being
+ * executed.
  */
-static int pm_noirq_op(struct device *dev, struct dev_pm_ops *ops,
+static int pm_noirq_op(struct device *dev,
+                       const struct dev_pm_ops *ops,
                        pm_message_t state)
 {
        int error = 0;
+       ktime_t calltime, delta, rettime;
+
+       if (initcall_debug) {
+               pr_info("calling  %s_i+ @ %i\n",
+                               dev_name(dev), task_pid_nr(current));
+               calltime = ktime_get();
+       }
 
        switch (state.event) {
 #ifdef CONFIG_SUSPEND
@@ -271,6 +322,15 @@ static int pm_noirq_op(struct device *dev, struct dev_pm_ops *ops,
        default:
                error = -EINVAL;
        }
+
+       if (initcall_debug) {
+               rettime = ktime_get();
+               delta = ktime_sub(rettime, calltime);
+               printk("initcall %s_i+ returned %d after %Ld usecs\n",
+                       dev_name(dev), error,
+                       (unsigned long long)ktime_to_ns(delta) >> 10);
+       }
+
        return error;
 }
 
@@ -312,82 +372,104 @@ static void pm_dev_err(struct device *dev, pm_message_t state, char *info,
                kobject_name(&dev->kobj), pm_verb(state.event), info, error);
 }
 
+static void dpm_show_time(ktime_t starttime, pm_message_t state, char *info)
+{
+       ktime_t calltime;
+       s64 usecs64;
+       int usecs;
+
+       calltime = ktime_get();
+       usecs64 = ktime_to_ns(ktime_sub(calltime, starttime));
+       do_div(usecs64, NSEC_PER_USEC);
+       usecs = usecs64;
+       if (usecs == 0)
+               usecs = 1;
+       pr_info("PM: %s%s%s of devices complete after %ld.%03ld msecs\n",
+               info ?: "", info ? " " : "", pm_verb(state.event),
+               usecs / USEC_PER_MSEC, usecs % USEC_PER_MSEC);
+}
+
 /*------------------------- Resume routines -------------------------*/
 
 /**
- *     resume_device_noirq - Power on one device (early resume).
- *     @dev:   Device.
- *     @state: PM transition of the system being carried out.
+ * device_resume_noirq - Execute an "early resume" callback for given device.
+ * @dev: Device to handle.
+ * @state: PM transition of the system being carried out.
  *
- *     Must be called with interrupts disabled.
+ * The driver of @dev will not receive interrupts while this function is being
+ * executed.
  */
-static int resume_device_noirq(struct device *dev, pm_message_t state)
+static int device_resume_noirq(struct device *dev, pm_message_t state)
 {
        int error = 0;
 
        TRACE_DEVICE(dev);
        TRACE_RESUME(0);
 
-       if (!dev->bus)
-               goto End;
-
-       if (dev->bus->pm) {
+       if (dev->bus && 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.
+ * dpm_resume_noirq - Execute "early resume" callbacks for non-sysdev devices.
+ * @state: PM transition of the system being carried out.
  *
- *     Execute the appropriate "noirq resume" callback for all devices marked
- *     as DPM_OFF_IRQ.
- *
- *     Must be called under dpm_list_mtx.  Device drivers should not receive
- *     interrupts while it's being executed.
+ * Call the "noirq" resume handlers for all devices marked as DPM_OFF_IRQ and
+ * enable device drivers to receive interrupts.
  */
-static void dpm_power_up(pm_message_t state)
+void dpm_resume_noirq(pm_message_t state)
 {
        struct device *dev;
+       ktime_t starttime = ktime_get();
 
+       mutex_lock(&dpm_list_mtx);
+       transition_started = false;
        list_for_each_entry(dev, &dpm_list, power.entry)
                if (dev->power.status > DPM_OFF) {
                        int error;
 
                        dev->power.status = DPM_OFF;
-                       error = resume_device_noirq(dev, state);
+                       error = device_resume_noirq(dev, state);
                        if (error)
                                pm_dev_err(dev, state, " early", error);
                }
+       mutex_unlock(&dpm_list_mtx);
+       dpm_show_time(starttime, state, "early");
+       resume_device_irqs();
 }
+EXPORT_SYMBOL_GPL(dpm_resume_noirq);
 
 /**
- *     device_power_up - Turn on all devices that need special attention.
- *     @state: PM transition of the system being carried out.
- *
- *     Call the "early" resume handlers and enable device drivers to receive
- *     interrupts.
+ * legacy_resume - Execute a legacy (bus or class) resume callback for device.
+ * @dev: Device to resume.
+ * @cb: Resume callback to execute.
  */
-void device_power_up(pm_message_t state)
+static int legacy_resume(struct device *dev, int (*cb)(struct device *dev))
 {
-       dpm_power_up(state);
-       resume_device_irqs();
+       int error;
+       ktime_t calltime;
+
+       calltime = initcall_debug_start(dev);
+
+       error = cb(dev);
+       suspend_report_result(cb, error);
+
+       initcall_debug_report(dev, calltime, error);
+
+       return error;
 }
-EXPORT_SYMBOL_GPL(device_power_up);
 
 /**
- *     resume_device - Restore state for one device.
- *     @dev:   Device.
- *     @state: PM transition of the system being carried out.
+ * device_resume - Execute "resume" callbacks for given device.
+ * @dev: Device to handle.
+ * @state: PM transition of the system being carried out.
  */
-static int resume_device(struct device *dev, pm_message_t state)
+static int device_resume(struct device *dev, pm_message_t state)
 {
        int error = 0;
 
@@ -402,7 +484,7 @@ static int resume_device(struct device *dev, pm_message_t state)
                        error = pm_op(dev, dev->bus->pm, state);
                } else if (dev->bus->resume) {
                        pm_dev_dbg(dev, state, "legacy ");
-                       error = dev->bus->resume(dev);
+                       error = legacy_resume(dev, dev->bus->resume);
                }
                if (error)
                        goto End;
@@ -412,9 +494,6 @@ static int resume_device(struct device *dev, pm_message_t state)
                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;
@@ -426,7 +505,7 @@ static int resume_device(struct device *dev, pm_message_t state)
                        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);
+                       error = legacy_resume(dev, dev->class->resume);
                }
        }
  End:
@@ -437,19 +516,19 @@ static int resume_device(struct device *dev, pm_message_t state)
 }
 
 /**
- *     dpm_resume - Resume every device.
- *     @state: PM transition of the system being carried out.
+ * dpm_resume - Execute "resume" callbacks for non-sysdev devices.
+ * @state: PM transition of the system being carried out.
  *
- *     Execute the appropriate "resume" callback for all devices the status of
- *     which indicates that they are inactive.
+ * Execute the appropriate "resume" callback for all devices whose status
+ * indicates that they are suspended.
  */
 static void dpm_resume(pm_message_t state)
 {
        struct list_head list;
+       ktime_t starttime = ktime_get();
 
        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);
 
@@ -460,7 +539,7 @@ static void dpm_resume(pm_message_t state)
                        dev->power.status = DPM_RESUMING;
                        mutex_unlock(&dpm_list_mtx);
 
-                       error = resume_device(dev, state);
+                       error = device_resume(dev, state);
 
                        mutex_lock(&dpm_list_mtx);
                        if (error)
@@ -475,14 +554,15 @@ static void dpm_resume(pm_message_t state)
        }
        list_splice(&list, &dpm_list);
        mutex_unlock(&dpm_list_mtx);
+       dpm_show_time(starttime, state, NULL);
 }
 
 /**
- *     complete_device - Complete a PM transition for given device
- *     @dev:   Device.
- *     @state: PM transition of the system being carried out.
+ * device_complete - Complete a PM transition for given device.
+ * @dev: Device to handle.
+ * @state: PM transition of the system being carried out.
  */
-static void complete_device(struct device *dev, pm_message_t state)
+static void device_complete(struct device *dev, pm_message_t state)
 {
        down(&dev->sem);
 
@@ -505,11 +585,11 @@ static void complete_device(struct device *dev, pm_message_t state)
 }
 
 /**
- *     dpm_complete - Complete a PM transition for all devices.
- *     @state: PM transition of the system being carried out.
+ * dpm_complete - Complete a PM transition for all non-sysdev devices.
+ * @state: PM transition of the system being carried out.
  *
- *     Execute the ->complete() callbacks for all devices that are not marked
- *     as DPM_ON.
+ * Execute the ->complete() callbacks for all devices whose PM status is not
+ * DPM_ON (this allows new devices to be registered).
  */
 static void dpm_complete(pm_message_t state)
 {
@@ -517,6 +597,7 @@ static void dpm_complete(pm_message_t state)
 
        INIT_LIST_HEAD(&list);
        mutex_lock(&dpm_list_mtx);
+       transition_started = false;
        while (!list_empty(&dpm_list)) {
                struct device *dev = to_device(dpm_list.prev);
 
@@ -525,7 +606,8 @@ static void dpm_complete(pm_message_t state)
                        dev->power.status = DPM_ON;
                        mutex_unlock(&dpm_list_mtx);
 
-                       complete_device(dev, state);
+                       device_complete(dev, state);
+                       pm_runtime_put_sync(dev);
 
                        mutex_lock(&dpm_list_mtx);
                }
@@ -538,27 +620,29 @@ static void dpm_complete(pm_message_t state)
 }
 
 /**
- *     device_resume - Restore state of each device in system.
- *     @state: PM transition of the system being carried out.
+ * dpm_resume_end - Execute "resume" callbacks and complete system transition.
+ * @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.
+ * Execute "resume" callbacks for all devices and complete the PM transition of
+ * the system.
  */
-void device_resume(pm_message_t state)
+void dpm_resume_end(pm_message_t state)
 {
        might_sleep();
        dpm_resume(state);
        dpm_complete(state);
 }
-EXPORT_SYMBOL_GPL(device_resume);
+EXPORT_SYMBOL_GPL(dpm_resume_end);
 
 
 /*------------------------- Suspend routines -------------------------*/
 
 /**
- *     resume_event - return a PM message representing the resume event
- *                    corresponding to given sleep state.
- *     @sleep_state: PM message representing a sleep state.
+ * resume_event - Return a "resume" message for given "suspend" sleep state.
+ * @sleep_state: PM message representing a sleep state.
+ *
+ * Return a PM message representing the resume event corresponding to given
+ * sleep state.
  */
 static pm_message_t resume_event(pm_message_t sleep_state)
 {
@@ -575,65 +659,84 @@ static pm_message_t resume_event(pm_message_t sleep_state)
 }
 
 /**
- *     suspend_device_noirq - Shut down one device (late suspend).
- *     @dev:   Device.
- *     @state: PM transition of the system being carried out.
+ * device_suspend_noirq - Execute a "late suspend" callback for given device.
+ * @dev: Device to handle.
+ * @state: PM transition of the system being carried out.
  *
- *     This is called with interrupts off and only a single CPU running.
+ * The driver of @dev will not receive interrupts while this function is being
+ * executed.
  */
-static int suspend_device_noirq(struct device *dev, pm_message_t state)
+static int device_suspend_noirq(struct device *dev, pm_message_t state)
 {
        int error = 0;
 
-       if (!dev->bus)
-               return 0;
-
-       if (dev->bus->pm) {
+       if (dev->bus && 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);
        }
        return error;
 }
 
 /**
- *     device_power_down - Shut down special devices.
- *     @state: PM transition of the system being carried out.
+ * dpm_suspend_noirq - Execute "late suspend" callbacks for non-sysdev devices.
+ * @state: PM transition of the system being carried out.
  *
- *     Prevent device drivers from receiving interrupts and call the "late"
- *     suspend handlers.
- *
- *     Must be called under dpm_list_mtx.
+ * Prevent device drivers from receiving interrupts and call the "noirq" suspend
+ * handlers for all non-sysdev devices.
  */
-int device_power_down(pm_message_t state)
+int dpm_suspend_noirq(pm_message_t state)
 {
        struct device *dev;
+       ktime_t starttime = ktime_get();
        int error = 0;
 
        suspend_device_irqs();
+       mutex_lock(&dpm_list_mtx);
        list_for_each_entry_reverse(dev, &dpm_list, power.entry) {
-               error = suspend_device_noirq(dev, state);
+               error = device_suspend_noirq(dev, state);
                if (error) {
                        pm_dev_err(dev, state, " late", error);
                        break;
                }
                dev->power.status = DPM_OFF_IRQ;
        }
+       mutex_unlock(&dpm_list_mtx);
        if (error)
-               device_power_up(resume_event(state));
+               dpm_resume_noirq(resume_event(state));
+       else
+               dpm_show_time(starttime, state, "late");
+       return error;
+}
+EXPORT_SYMBOL_GPL(dpm_suspend_noirq);
+
+/**
+ * legacy_suspend - Execute a legacy (bus or class) suspend callback for device.
+ * @dev: Device to suspend.
+ * @state: PM transition of the system being carried out.
+ * @cb: Suspend callback to execute.
+ */
+static int legacy_suspend(struct device *dev, pm_message_t state,
+                         int (*cb)(struct device *dev, pm_message_t state))
+{
+       int error;
+       ktime_t calltime;
+
+       calltime = initcall_debug_start(dev);
+
+       error = cb(dev, state);
+       suspend_report_result(cb, error);
+
+       initcall_debug_report(dev, calltime, error);
+
        return error;
 }
-EXPORT_SYMBOL_GPL(device_power_down);
 
 /**
- *     suspend_device - Save state of one device.
- *     @dev:   Device.
- *     @state: PM transition of the system being carried out.
+ * device_suspend - Execute "suspend" callbacks for given device.
+ * @dev: Device to handle.
+ * @state: PM transition of the system being carried out.
  */
-static int suspend_device(struct device *dev, pm_message_t state)
+static int device_suspend(struct device *dev, pm_message_t state)
 {
        int error = 0;
 
@@ -645,8 +748,7 @@ static int suspend_device(struct device *dev, pm_message_t state)
                        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);
+                       error = legacy_suspend(dev, state, dev->class->suspend);
                }
                if (error)
                        goto End;
@@ -656,10 +758,6 @@ static int suspend_device(struct device *dev, pm_message_t state)
                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;
@@ -671,8 +769,7 @@ static int suspend_device(struct device *dev, pm_message_t state)
                        error = pm_op(dev, dev->bus->pm, 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);
+                       error = legacy_suspend(dev, state, dev->bus->suspend);
                }
        }
  End:
@@ -682,14 +779,13 @@ static int suspend_device(struct device *dev, pm_message_t state)
 }
 
 /**
- *     dpm_suspend - Suspend every device.
- *     @state: PM transition of the system being carried out.
- *
- *     Execute the appropriate "suspend" callbacks for all devices.
+ * dpm_suspend - Execute "suspend" callbacks for all non-sysdev devices.
+ * @state: PM transition of the system being carried out.
  */
 static int dpm_suspend(pm_message_t state)
 {
        struct list_head list;
+       ktime_t starttime = ktime_get();
        int error = 0;
 
        INIT_LIST_HEAD(&list);
@@ -700,7 +796,7 @@ static int dpm_suspend(pm_message_t state)
                get_device(dev);
                mutex_unlock(&dpm_list_mtx);
 
-               error = suspend_device(dev, state);
+               error = device_suspend(dev, state);
 
                mutex_lock(&dpm_list_mtx);
                if (error) {
@@ -715,15 +811,20 @@ static int dpm_suspend(pm_message_t state)
        }
        list_splice(&list, dpm_list.prev);
        mutex_unlock(&dpm_list_mtx);
+       if (!error)
+               dpm_show_time(starttime, state, NULL);
        return error;
 }
 
 /**
- *     prepare_device - Execute the ->prepare() callback(s) for given device.
- *     @dev:   Device.
- *     @state: PM transition of the system being carried out.
+ * device_prepare - Prepare a device for system power transition.
+ * @dev: Device to handle.
+ * @state: PM transition of the system being carried out.
+ *
+ * Execute the ->prepare() callback(s) for given device.  No new children of the
+ * device may be registered after this function has returned.
  */
-static int prepare_device(struct device *dev, pm_message_t state)
+static int device_prepare(struct device *dev, pm_message_t state)
 {
        int error = 0;
 
@@ -757,10 +858,10 @@ static int prepare_device(struct device *dev, pm_message_t state)
 }
 
 /**
- *     dpm_prepare - Prepare all devices for a PM transition.
- *     @state: PM transition of the system being carried out.
+ * dpm_prepare - Prepare all non-sysdev devices for a system PM transition.
+ * @state: PM transition of the system being carried out.
  *
- *     Execute the ->prepare() callback for all devices.
+ * Execute the ->prepare() callback(s) for all devices.
  */
 static int dpm_prepare(pm_message_t state)
 {
@@ -777,13 +878,21 @@ static int dpm_prepare(pm_message_t state)
                dev->power.status = DPM_PREPARING;
                mutex_unlock(&dpm_list_mtx);
 
-               error = prepare_device(dev, state);
+               pm_runtime_get_noresume(dev);
+               if (pm_runtime_barrier(dev) && device_may_wakeup(dev)) {
+                       /* Wake-up requested during system sleep transition. */
+                       pm_runtime_put_sync(dev);
+                       error = -EBUSY;
+               } else {
+                       error = device_prepare(dev, state);
+               }
 
                mutex_lock(&dpm_list_mtx);
                if (error) {
                        dev->power.status = DPM_ON;
                        if (error == -EAGAIN) {
                                put_device(dev);
+                               error = 0;
                                continue;
                        }
                        printk(KERN_ERR "PM: Failed to prepare device %s "
@@ -803,12 +912,13 @@ static int dpm_prepare(pm_message_t state)
 }
 
 /**
- *     device_suspend - Save state and stop all devices in system.
- *     @state: PM transition of the system being carried out.
+ * dpm_suspend_start - Prepare devices for PM transition and suspend them.
+ * @state: PM transition of the system being carried out.
  *
- *     Prepare and suspend all devices.
+ * Prepare all non-sysdev devices for system PM transition and execute "suspend"
+ * callbacks for them.
  */
-int device_suspend(pm_message_t state)
+int dpm_suspend_start(pm_message_t state)
 {
        int error;
 
@@ -818,7 +928,7 @@ int device_suspend(pm_message_t state)
                error = dpm_suspend(state);
        return error;
 }
-EXPORT_SYMBOL_GPL(device_suspend);
+EXPORT_SYMBOL_GPL(dpm_suspend_start);
 
 void __suspend_report_result(const char *function, void *fn, int ret)
 {