USB / PM: Allow USB devices to remain runtime-suspended when sleeping

Have dev_pm_ops.prepare return 1 for USB devices and ports so that USB devices can remain runtime-suspended when the system goes to a sleep state, if their wakeup state is correct and they have runtime PM enabled. Signed-off-by: Tomeu Vizoso <[email protected]> Reviewed-by: Ulf Hansson <[email protected]> Acked-by: Alan Stern <[email protected]> Signed-off-by: Rafael J. Wysocki <[email protected]>
iegor · Jan 8, 2016 · e3345db · e3345db
1 parent aa8e54b
commit e3345db
Show file tree

Hide file tree

Showing 2 changed files with 13 additions and 1 deletion.
diff --git a/drivers/usb/core/port.c b/drivers/usb/core/port.c
@@ -168,12 +168,18 @@ static int usb_port_runtime_suspend(struct device *dev)
 
 	return retval;
 }
+
+static int usb_port_prepare(struct device *dev)
+{
+	return 1;
+}
 #endif
 
 static const struct dev_pm_ops usb_port_pm_ops = {
 #ifdef CONFIG_PM
 	.runtime_suspend =	usb_port_runtime_suspend,
 	.runtime_resume =	usb_port_runtime_resume,
+	.prepare =		usb_port_prepare,
 #endif
 };
 

diff --git a/drivers/usb/core/usb.c b/drivers/usb/core/usb.c
@@ -316,7 +316,13 @@ static int usb_dev_uevent(struct device *dev, struct kobj_uevent_env *env)
 
 static int usb_dev_prepare(struct device *dev)
 {
-	return 0;		/* Implement eventually? */
+	struct usb_device *udev = to_usb_device(dev);
+
+	/* Return 0 if the current wakeup setting is wrong, otherwise 1 */
+	if (udev->do_remote_wakeup != device_may_wakeup(dev))
+		return 0;
+
+	return 1;
 }
 
 static void usb_dev_complete(struct device *dev)