1 files changed, 25 insertions, 2 deletions

diff --git a/drivers/scsi/scsi_pm.c b/drivers/scsi/scsi_pm.c
index d329f8b12e2b..bf8bf79e6a1f 100644
--- a/drivers/scsi/scsi_pm.c
+++ b/drivers/scsi/scsi_pm.c
@@ -49,8 +49,22 @@ static int scsi_bus_suspend_common(struct device *dev, pm_message_t msg)
 {
 	int err = 0;
 
-	if (scsi_is_sdev_device(dev))
+	if (scsi_is_sdev_device(dev)) {
+		/*
+		 * sd is the only high-level SCSI driver to implement runtime
+		 * PM, and sd treats runtime suspend, system suspend, and
+		 * system hibernate identically (but not system freeze).
+		 */
+		if (pm_runtime_suspended(dev)) {
+			if (msg.event == PM_EVENT_SUSPEND ||
+			    msg.event == PM_EVENT_HIBERNATE)
+				return 0;	/* already suspended */
+
+			/* wake up device so that FREEZE will succeed */
+			pm_runtime_resume(dev);
+		}
 		err = scsi_dev_type_suspend(dev, msg);
+	}
 	return err;
 }
 
@@ -58,8 +72,17 @@ static int scsi_bus_resume_common(struct device *dev)
 {
 	int err = 0;
 
-	if (scsi_is_sdev_device(dev))
+	if (scsi_is_sdev_device(dev)) {
+		/*
+		 * Parent device may have runtime suspended as soon as
+		 * it is woken up during the system resume.
+		 *
+		 * Resume it on behalf of child.
+		 */
+		pm_runtime_get_sync(dev->parent);
 		err = scsi_dev_type_resume(dev);
+		pm_runtime_put_sync(dev->parent);
+	}
 
 	if (err == 0) {
 		pm_runtime_disable(dev);