1 files changed, 25 insertions, 0 deletions
diff --git a/drivers/acpi/glue.c b/drivers/acpi/glue.c
index ef104809f27b..7cd0009e7ff3 100644
--- a/drivers/acpi/glue.c
+++ b/drivers/acpi/glue.c
@@ -347,3 +347,28 @@ void acpi_device_notify_remove(struct device *dev)
 
 	acpi_unbind_one(dev);
 }
+
+int acpi_dev_turn_off_if_unused(struct device *dev, void *not_used)
+{
+	struct acpi_device *adev = to_acpi_device(dev);
+
+	/*
+	 * Skip device objects with device IDs, because they may be in use even
+	 * if they are not companions of any physical device objects.
+	 */
+	if (adev->pnp.type.hardware_id)
+		return 0;
+
+	mutex_lock(&adev->physical_node_lock);
+
+	/*
+	 * Device objects without device IDs are not in use if they have no
+	 * corresponding physical device objects.
+	 */
+	if (list_empty(&adev->physical_node_list))
+		acpi_device_set_power(adev, ACPI_STATE_D3_COLD);
+
+	mutex_unlock(&adev->physical_node_lock);
+
+	return 0;
+}