1 files changed, 84 insertions, 18 deletions

diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c
index 08744b572af6..6e8cc5de93fd 100644
--- a/drivers/base/power/main.c
+++ b/drivers/base/power/main.c
@@ -18,7 +18,6 @@
  */
 
 #include <linux/device.h>
-#include <linux/kallsyms.h>
 #include <linux/export.h>
 #include <linux/mutex.h>
 #include <linux/pm.h>
@@ -541,6 +540,18 @@ void dev_pm_skip_next_resume_phases(struct device *dev)
 }
 
 /**
+ * dev_pm_may_skip_resume - System-wide device resume optimization check.
+ * @dev: Target device.
+ *
+ * Checks whether or not the device may be left in suspend after a system-wide
+ * transition to the working state.
+ */
+bool dev_pm_may_skip_resume(struct device *dev)
+{
+	return !dev->power.must_resume && pm_transition.event != PM_EVENT_RESTORE;
+}
+
+/**
  * device_resume_noirq - Execute a "noirq resume" callback for given device.
  * @dev: Device to handle.
  * @state: PM transition of the system being carried out.
@@ -588,6 +599,18 @@ static int device_resume_noirq(struct device *dev, pm_message_t state, bool asyn
 	error = dpm_run_callback(callback, dev, state, info);
 	dev->power.is_noirq_suspended = false;
 
+	if (dev_pm_may_skip_resume(dev)) {
+		/*
+		 * The device is going to be left in suspend, but it might not
+		 * have been in runtime suspend before the system suspended, so
+		 * its runtime PM status needs to be updated to avoid confusing
+		 * the runtime PM framework when runtime PM is enabled for the
+		 * device again.
+		 */
+		pm_runtime_set_suspended(dev);
+		dev_pm_skip_next_resume_phases(dev);
+	}
+
  Out:
 	complete_all(&dev->power.completion);
 	TRACE_RESUME(error);
@@ -1089,6 +1112,22 @@ static pm_message_t resume_event(pm_message_t sleep_state)
 	return PMSG_ON;
 }
 
+static void dpm_superior_set_must_resume(struct device *dev)
+{
+	struct device_link *link;
+	int idx;
+
+	if (dev->parent)
+		dev->parent->power.must_resume = true;
+
+	idx = device_links_read_lock();
+
+	list_for_each_entry_rcu(link, &dev->links.suppliers, c_node)
+		link->supplier->power.must_resume = true;
+
+	device_links_read_unlock(idx);
+}
+
 /**
  * __device_suspend_noirq - Execute a "noirq suspend" callback for given device.
  * @dev: Device to handle.
@@ -1140,10 +1179,28 @@ static int __device_suspend_noirq(struct device *dev, pm_message_t state, bool a
 	}
 
 	error = dpm_run_callback(callback, dev, state, info);
-	if (!error)
-		dev->power.is_noirq_suspended = true;
-	else
+	if (error) {
 		async_error = error;
+		goto Complete;
+	}
+
+	dev->power.is_noirq_suspended = true;
+
+	if (dev_pm_test_driver_flags(dev, DPM_FLAG_LEAVE_SUSPENDED)) {
+		/*
+		 * The only safe strategy here is to require that if the device
+		 * may not be left in suspend, resume callbacks must be invoked
+		 * for it.
+		 */
+		dev->power.must_resume = dev->power.must_resume ||
+					!dev->power.may_skip_resume ||
+					atomic_read(&dev->power.usage_count) > 1;
+	} else {
+		dev->power.must_resume = true;
+	}
+
+	if (dev->power.must_resume)
+		dpm_superior_set_must_resume(dev);
 
 Complete:
 	complete_all(&dev->power.completion);
@@ -1435,6 +1492,22 @@ static int legacy_suspend(struct device *dev, pm_message_t state,
 	return error;
 }
 
+static void dpm_propagate_to_parent(struct device *dev)
+{
+	struct device *parent = dev->parent;
+
+	if (!parent)
+		return;
+
+	spin_lock_irq(&parent->power.lock);
+
+	parent->power.direct_complete = false;
+	if (dev->power.wakeup_path && !parent->power.ignore_children)
+		parent->power.wakeup_path = true;
+
+	spin_unlock_irq(&parent->power.lock);
+}
+
 static void dpm_clear_suppliers_direct_complete(struct device *dev)
 {
 	struct device_link *link;
@@ -1500,6 +1573,9 @@ static int __device_suspend(struct device *dev, pm_message_t state, bool async)
 		dev->power.direct_complete = false;
 	}
 
+	dev->power.may_skip_resume = false;
+	dev->power.must_resume = false;
+
 	dpm_watchdog_set(&wd, dev);
 	device_lock(dev);
 
@@ -1543,19 +1619,8 @@ static int __device_suspend(struct device *dev, pm_message_t state, bool async)
 
  End:
 	if (!error) {
-		struct device *parent = dev->parent;
-
 		dev->power.is_suspended = true;
-		if (parent) {
-			spin_lock_irq(&parent->power.lock);
-
-			dev->parent->power.direct_complete = false;
-			if (dev->power.wakeup_path
-			    && !dev->parent->power.ignore_children)
-				dev->parent->power.wakeup_path = true;
-
-			spin_unlock_irq(&parent->power.lock);
-		}
+		dpm_propagate_to_parent(dev);
 		dpm_clear_suppliers_direct_complete(dev);
 	}
 
@@ -1665,8 +1730,9 @@ static int device_prepare(struct device *dev, pm_message_t state)
 	if (dev->power.syscore)
 		return 0;
 
-	WARN_ON(dev_pm_test_driver_flags(dev, DPM_FLAG_SMART_SUSPEND) &&
-		!pm_runtime_enabled(dev));
+	WARN_ON(!pm_runtime_enabled(dev) &&
+		dev_pm_test_driver_flags(dev, DPM_FLAG_SMART_SUSPEND |
+					      DPM_FLAG_LEAVE_SUSPENDED));
 
 	/*
 	 * If a device's parent goes into runtime suspend at the wrong time,