+ usb_autopm_get_interface_async() and
+ usb_autopm_put_interface_async() do almost the same things as
+ their non-async counterparts. The differences are: they do
+ not acquire the PM mutex, and they use a workqueue to do their
+ jobs. As a result they can be called in an atomic context,
+ such as an URB's completion handler, but when they return the
+ device will not generally not yet be in the desired state.
+