android sharedpreferences_android S

root@android:/ # ls /sys/power/ 
pm_async
state
wait_for_fb_sleep
wait_for_fb_wake
wake_lock
wake_unlock
wakeup_count

static ssize_t state_store(struct kobject *kobj, struct kobj_attribute *attr,  
               const char *buf, size_t n)  
              request_suspend_state(state);//这里，进入了Android的休眠与唤醒的处理函数  

if (!old_sleep && new_state != PM_SUSPEND_ON) {  
        state |= SUSPEND_REQUESTED;  
        queue_work(suspend_work_queue, &early_suspend_work);//在休眠的时候，去遍历执行early_suspend_work这个队列  
    } else if (old_sleep && new_state == PM_SUSPEND_ON) {  
        state &= ~SUSPEND_REQUESTED;  
        wake_lock(&main_wake_lock);  
        queue_work(suspend_work_queue, &late_resume_work);//在唤醒的时候，去遍历执行late_resume_work这个队列  
    }     


int pm_suspend(suspend_state_t state)  
{  
    if (state > PM_SUSPEND_ON && state < PM_SUSPEND_MAX)  
        return enter_state(state);//正如你所料，开始走Linux那套休眠的流程了  
    return -EINVAL;  
}  

struct early_suspend    early_suspend;
early_suspend.level = EARLY_SUSPEND_LEVEL_BLANK_SCREEN + 1; //等级，等级大小和suspend顺序一致，和resume顺序相反
early_suspend.suspend = xxx_early_suspend;//指定函数指针，需自己实现
early_suspend.resume = xxx_late_resume;
register_early_suspend(&early_suspend);//注册进核心，也就是加入刚才early_suspend_handlers那个链表

struct wake_lock    chrg_lock;
wake_lock_init(&chrg_lock, WAKE_LOCK_SUSPEND, "xxx_wake_lock");//初始化类型为WAKE_LOCK_SUSPEND的wake_lock锁
#ifdef CONFIG_HAS_EARLYSUSPEND
static void xxx_early_suspend(struct early_suspend *h)
{
       ....
        wake_lock(&chrg_lock);
      ....
}
static void xxx_late_resume(struct early_suspend *h)
{
     .....
        wake_unlock(&chrg_lock);
     ....
}
#endif