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android v2.3linux v2.6.37wakelock 和 early_suspend能够实现系统的唤醒和休眠功能1.wakelockwakelock是一种锁机制，只要有人拿着这个锁，系统就无法进入休眠，wakelock有加锁解锁二种状态超时锁：在设定的时间到了后自动解锁不超时锁：需要显示的解锁include/linux/wakelock.henum { WAKE_LOCK_SUSPEND, //防止系统进入睡眠 WAKE_LOCK_IDLE, WAKE_LOCK_TYPE_COUNT};2.early_suspend 在linux 内核的睡眠过程前被调用，因为背光需要的电能大，可以在内核中先注册上early_suspend函数当系统进入睡眠之前会首先调用这些注册的函数android休眠唤醒的的文件kernel/power/console.cearlysuspend.cfbearlysuspend.cmain.cpoweroff.csuspend.cwakelock.cuserwakelock.carch/arm/mach-omap2/pm34xx.c pm.c3.android 休眠当用户读写/sys/power/state时，/kernel/power/main.c中的state_store()函数会被调用# echo mem > sys/power/state [ 61.009735] ------state_store------ [ 61.013366] ------request_suspend_state------ [ 61.017944] request_suspend_state: sleep (0->3) at 61399169254 (2000-01-01 00:00:56.084929752 UTC) [ 61.027496] ------early_suspend------ state_store会调用request_suspend_state()然后调用early_suspend_work的工作队列void request_suspend_state(suspend_state_t new_state){ --------------------- queue_work(suspend_work_queue, &early_suspend_work); ---------------------}static DECLARE_WORK(early_suspend_work, early_suspend);early_suspend_work的工作队列进入early_suspend()函数中static void early_suspend(struct work_struct *work){ ------------------- //调用已经注册的early_suspend函数 list_for_each_entry(pos, &early_suspend_handlers, link) { if (pos->suspend != NULL) pos->suspend(pos); } ------------------ sys_sync();//同步文件系统}4. android 唤醒# echo on > sys/power/state [ 582.205108] ------state_store------ [ 582.208740] ------request_suspend_state------ [ 582.213317] request_suspend_state: wakeup (3->0) at 582594543042 (2000-01-01 00:09:37.501769604 UTC) [ 582.222839] ------late_resume------ 跟睡眠的过程相反 转载地址：http://hakni.baihongyu.com/