1. Linux之 4 种休眠模式

# echo standby >/sys/power/state //CPU和RAM在运行
# echo mem > /sys/power/state  //挂起到内存(待机),关闭硬 盘、外设等设备
# echo disk > /sys/power/state //挂起到硬盘(休眠),关闭硬盘、外设等设备，进入关机状态。此时计算机
完全关闭，不耗电 
# echo on > /sys/power/state  //退出休眠
# echo +10 > /sys/class/rtc/rtc0/wakealarm //10s后rtc唤醒cpu- On（on）                  S0 -  Working
- Standby （standby）       S1 -  CPU and RAM are powered but not executed
- Suspend to RAM（mem)      S3 -  RAM is powered and the running content is saved to RAM
- Suspend to Disk，Hibernation（disk） S4 -  All content is saved to Disk and power down2.查看电源状态
//查看当前睡眠情况
# cat /sys/power/state//查看当前那些占用了阻止深度睡眠的wake lock                                                                           
# cat /sys/power/wake_lock      //查看wake lock状态情况                                                           
# cat /sys/proc/wakelocks//手动释放一次名称为“PowerManagerSerivce”的wake lock引用次数-1，为0时进入睡眠                                                                     
#cat "PowerManagerService" > /sys/power/wake_unlock