power_work
INIT_WORK(&udc->power_job, power_work);
struct delayed_work power_work;
container_of(work, struct snd_ac97, power_work.work));
INIT_DELAYED_WORK(&ac97->power_work, do_update_power);
schedule_delayed_work(&ac97->power_work, secs_to_jiffies(power_save));
cancel_delayed_work(&ac97->power_work);
cancel_delayed_work_sync(&ac97->power_work);
cancel_delayed_work_sync(&ac97->power_work);