clockevents_exchange_device
clockevents_exchange_device(curdev, newdev);
clockevents_exchange_device(cur, dev);
clockevents_exchange_device(td->evtdev, newdev);
clockevents_exchange_device(curdev, newdev);
clockevents_exchange_device(dev, NULL);
extern void clockevents_exchange_device(struct clock_event_device *old,