intf
This routine does much the same thing as usb_autopm_get_interface: It increments intf's usage counter and queues an autoresume request if the device is suspended. The differences are that it does not perform any synchronization (callers should hold a private lock and handle all synchronization issues themselves), and it does not autoresume the device directly (it only queues a request). After a successful call, the device may not yet be resumed.
This routine can run in atomic context.