linux之待机流程

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采用wakeup source 机制，wakeup source 是一种suspend blocker，它阻碍系统进入休眠

起点：sys/power/autosleep 写入mem；off

→pm_autosleep_set_state(state) //----------------kernel/kernel/power/main.c

∣↘queue_up_suspend_work()

∣↘try_to_suspend()

∣↘pm_get_wakeup_count()//-----------判断当前是否有wakeup_lock

∣↘pm_suspend()//----------------打印开始进入suspend的时间

∣↘enter_state() [PM:suspend entry 年月日]

∣↘sys_sync(); [PM:syncying file systems …done]

∣↘suspend_prepare() //-----------all user serves suspendhere

∣↘pm_prepare_console()

∣↘pm_notifier_call_chain()

∣↘suspend_freeze_processes()

∣↘freeze_proceses()

∣↘freeze_kernel_threads()

∣↘suspend_devices_and_enter() //all extern devices supend here

∣↘suspend_ops->begin()

∣↘suspend_console() [use no_console_suspend to debug]

∣↘dpm_suspend_start()

∣↘dpm_prepare()

∣↘device_prepare

∣↘dpm_suspend()

∣↘device_suspend [pm:suspend of devicescomplete after…所有设备-----再次检查是否有wakeup_lock持有]

∣↘__device_suspend

∣↘dev->class->suspend/dev->bus->suspend---------------调用真正驱动中定义的supend函数

∣↘suspend_enter()

∣↘suspend_ops_prepare()

∣↘dpm_suspend_end()

∣↘dpm_suspend_late() [pm:latesuspend of]

∣↘dpm_suspend_noirq() [pm:noirq suspend of]

∣↘suspend_ops->prepare_late()//准备待机,进行检查

∣↘disable_nonboot_cpus() [disabling non_boot cpus…]

∣↘arch_suspend_disable_iqrs()

∣↘syscore_suspend()

∣↘suspend_ops->enter()//检查没有问题真正待机

∣↘lpm_suspend_enter() [深待机，可输出GPIO，clock, LDO信息]

∣↘lpm_enter_low_power()

∣↘msm_cpu_pm_enter_sleep()

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