4 files changed, 64 insertions, 7 deletions

diff --git a/drivers/base/power/common.c b/drivers/base/power/common.c
index f32b802..f48e333 100644
--- a/drivers/base/power/common.c
+++ b/drivers/base/power/common.c
@@ -112,7 +112,7 @@ EXPORT_SYMBOL_GPL(dev_pm_domain_attach);
 
 /**
  * dev_pm_domain_detach - Detach a device from its PM domain.
- * @dev: Device to attach.
+ * @dev: Device to detach.
  * @power_off: Used to indicate whether we should power off the device.
  *
  * This functions will reverse the actions from dev_pm_domain_attach() and thus
diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c
index 1710c26..9d626ac 100644
--- a/drivers/base/power/main.c
+++ b/drivers/base/power/main.c
@@ -963,6 +963,9 @@ void dpm_complete(pm_message_t state)
 	}
 	list_splice(&list, &dpm_list);
 	mutex_unlock(&dpm_list_mtx);
+
+	/* Allow device probing and trigger re-probing of deferred devices */
+	device_unblock_probing();
 	trace_suspend_resume(TPS("dpm_complete"), state.event, false);
 }
 
@@ -1624,6 +1627,20 @@ int dpm_prepare(pm_message_t state)
 	trace_suspend_resume(TPS("dpm_prepare"), state.event, true);
 	might_sleep();
 
+	/*
+	 * Give a chance for the known devices to complete their probes, before
+	 * disable probing of devices. This sync point is important at least
+	 * at boot time + hibernation restore.
+	 */
+	wait_for_device_probe();
+	/*
+	 * It is unsafe if probing of devices will happen during suspend or
+	 * hibernation and system behavior will be unpredictable in this case.
+	 * So, let's prohibit device's probing here and defer their probes
+	 * instead. The normal behavior will be restored in dpm_complete().
+	 */
+	device_block_probing();
+
 	mutex_lock(&dpm_list_mtx);
 	while (!list_empty(&dpm_list)) {
 		struct device *dev = to_device(dpm_list.next);
diff --git a/drivers/base/power/power.h b/drivers/base/power/power.h
index 998fa6b..8b06193 100644
--- a/drivers/base/power/power.h
+++ b/drivers/base/power/power.h
@@ -18,6 +18,7 @@ static inline void pm_runtime_early_init(struct device *dev)
 }
 
 extern void pm_runtime_init(struct device *dev);
+extern void pm_runtime_reinit(struct device *dev);
 extern void pm_runtime_remove(struct device *dev);
 
 struct wake_irq {
@@ -84,6 +85,7 @@ static inline void pm_runtime_early_init(struct device *dev)
 }
 
 static inline void pm_runtime_init(struct device *dev) {}
+static inline void pm_runtime_reinit(struct device *dev) {}
 static inline void pm_runtime_remove(struct device *dev) {}
 
 static inline int dpm_sysfs_add(struct device *dev) { return 0; }
diff --git a/drivers/base/power/runtime.c b/drivers/base/power/runtime.c
index e1a10a0..4c70550 100644
--- a/drivers/base/power/runtime.c
+++ b/drivers/base/power/runtime.c
@@ -966,6 +966,30 @@ int __pm_runtime_resume(struct device *dev, int rpmflags)
 EXPORT_SYMBOL_GPL(__pm_runtime_resume);
 
 /**
+ * pm_runtime_get_if_in_use - Conditionally bump up the device's usage counter.
+ * @dev: Device to handle.
+ *
+ * Return -EINVAL if runtime PM is disabled for the device.
+ *
+ * If that's not the case and if the device's runtime PM status is RPM_ACTIVE
+ * and the runtime PM usage counter is nonzero, increment the counter and
+ * return 1.  Otherwise return 0 without changing the counter.
+ */
+int pm_runtime_get_if_in_use(struct device *dev)
+{
+	unsigned long flags;
+	int retval;
+
+	spin_lock_irqsave(&dev->power.lock, flags);
+	retval = dev->power.disable_depth > 0 ? -EINVAL :
+		dev->power.runtime_status == RPM_ACTIVE
+			&& atomic_inc_not_zero(&dev->power.usage_count);
+	spin_unlock_irqrestore(&dev->power.lock, flags);
+	return retval;
+}
+EXPORT_SYMBOL_GPL(pm_runtime_get_if_in_use);
+
+/**
  * __pm_runtime_set_status - Set runtime PM status of a device.
  * @dev: Device to handle.
  * @status: New runtime PM status of the device.
@@ -1390,18 +1414,32 @@ void pm_runtime_init(struct device *dev)
 }
 
 /**
+ * pm_runtime_reinit - Re-initialize runtime PM fields in given device object.
+ * @dev: Device object to re-initialize.
+ */
+void pm_runtime_reinit(struct device *dev)
+{
+	if (!pm_runtime_enabled(dev)) {
+		if (dev->power.runtime_status == RPM_ACTIVE)
+			pm_runtime_set_suspended(dev);
+		if (dev->power.irq_safe) {
+			spin_lock_irq(&dev->power.lock);
+			dev->power.irq_safe = 0;
+			spin_unlock_irq(&dev->power.lock);
+			if (dev->parent)
+				pm_runtime_put(dev->parent);
+		}
+	}
+}
+
+/**
  * pm_runtime_remove - Prepare for removing a device from device hierarchy.
  * @dev: Device object being removed from device hierarchy.
  */
 void pm_runtime_remove(struct device *dev)
 {
 	__pm_runtime_disable(dev, false);
-
-	/* Change the status back to 'suspended' to match the initial status. */
-	if (dev->power.runtime_status == RPM_ACTIVE)
-		pm_runtime_set_suspended(dev);
-	if (dev->power.irq_safe && dev->parent)
-		pm_runtime_put(dev->parent);
+	pm_runtime_reinit(dev);
 }
 
 /**