intf
This routine does much the same thing as usb_autopm_put_interface: It decrements intf's usage counter and schedules a delayed autosuspend request if the counter is <= 0. The difference is that it does not perform any synchronization; callers should hold a private lock and handle all synchronization issues themselves.
Typically a driver would call this routine during an URB's completion handler, if no more URBs were pending.
This routine can run in atomic context.