1 files changed, 30 insertions, 5 deletions

diff --git a/drivers/base/power/runtime.c b/drivers/base/power/runtime.c
index 60ebb04d8140..f0d863089345 100644
--- a/drivers/base/power/runtime.c
+++ b/drivers/base/power/runtime.c
@@ -1489,6 +1489,16 @@ int pm_runtime_force_suspend(struct device *dev)
         if (ret)
                 goto err;
 
+        /*
+         * Increase the runtime PM usage count for the device's parent, in case
+         * when we find the device being used when system suspend was invoked.
+         * This informs pm_runtime_force_resume() to resume the parent
+         * immediately, which is needed to be able to resume its children,
+         * when not deferring the resume to be managed via runtime PM.
+         */
+        if (dev->parent && atomic_read(&dev->power.usage_count) > 1)
+                pm_runtime_get_noresume(dev->parent);
+
         pm_runtime_set_suspended(dev);
         return 0;
 err:
@@ -1498,16 +1508,20 @@ err:
 EXPORT_SYMBOL_GPL(pm_runtime_force_suspend);
 
 /**
- * pm_runtime_force_resume - Force a device into resume state.
+ * pm_runtime_force_resume - Force a device into resume state if needed.
  * @dev: Device to resume.
  *
  * Prior invoking this function we expect the user to have brought the device
  * into low power state by a call to pm_runtime_force_suspend(). Here we reverse
- * those actions and brings the device into full power. We update the runtime PM
- * status and re-enables runtime PM.
+ * those actions and brings the device into full power, if it is expected to be
+ * used on system resume. To distinguish that, we check whether the runtime PM
+ * usage count is greater than 1 (the PM core increases the usage count in the
+ * system PM prepare phase), as that indicates a real user (such as a subsystem,
+ * driver, userspace, etc.) is using it. If that is the case, the device is
+ * expected to be used on system resume as well, so then we resume it. In the
+ * other case, we defer the resume to be managed via runtime PM.
  *
- * Typically this function may be invoked from a system resume callback to make
- * sure the device is put into full power state.
+ * Typically this function may be invoked from a system resume callback.
  */
 int pm_runtime_force_resume(struct device *dev)
 {
@@ -1524,6 +1538,17 @@ int pm_runtime_force_resume(struct device *dev)
         if (!pm_runtime_status_suspended(dev))
                 goto out;
 
+        /*
+         * Decrease the parent's runtime PM usage count, if we increased it
+         * during system suspend in pm_runtime_force_suspend().
+        */
+        if (atomic_read(&dev->power.usage_count) > 1) {
+                if (dev->parent)
+                        pm_runtime_put_noidle(dev->parent);
+        } else {
+                goto out;
+        }
+
         ret = pm_runtime_set_active(dev);
         if (ret)
                 goto out;