为什么wakeup_sources里有active_since属性不等于0的项时不休眠

为什么/sys/kernel/debug/wakeup_sources下面有active_since属性不等于0的项时系统不休眠




wakeup events framework代码在:  /kernel/drivers/base/power/wakeup.c中实现。在wakeup events framework中重要的数据结构就是wakeup_source，字面意思就是产生wakeup events的设备。

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/**

 * struct wakeup_source - Representation of wakeup sources

 *

 * @total_time: Total time this wakeup source has been active.

 * @max_time: Maximum time this wakeup source has been continuously active.

 * @last_time: Monotonic clock when the wakeup source's was touched last time.

 * @prevent_sleep_time: Total time this source has been preventing autosleep.

 * @event_count: Number of signaled wakeup events.

 * @active_count: Number of times the wakeup source was activated.

 * @relax_count: Number of times the wakeup source was deactivated.

 * @expire_count: Number of times the wakeup source's timeout has expired.

 * @wakeup_count: Number of times the wakeup source might abort suspend.

 * @active: Status of the wakeup source.

 * @has_timeout: The wakeup source has been activated with a timeout.

 */

struct wakeup_source {

        const char                 *name;

        struct list_head        entry;

        spinlock_t                lock;

        struct timer_list        timer;

        unsigned long                timer_expires;

        ktime_t total_time;

        ktime_t max_time;

        ktime_t last_time;

        ktime_t start_prevent_time;

        ktime_t prevent_sleep_time;

        unsigned long                event_count;

        unsigned long                active_count;

        unsigned long                relax_count;

        unsigned long                expire_count;

        unsigned long                wakeup_count;

        bool                        active:1;

        bool                        autosleep_enabled:1;

};

.name:    唤醒源的名字。
.entry:     用来将唤醒源挂到链表上，用于管理。
.lock:       同步机制，用于访问链表时使用。
.timer:     定时器，用于设置该唤醒源的超时时间。
.timer_expires:  定时器的超时时间。
.total_time:  wakeup source处于active状态的总时间。
.max_time:  wakeup source处于active状态的最长时间。
.last_time:   wakeup source处于active状态的上次时间。
.start_prevent_time:   wakeup source阻止autosleep的开始时间。
.prevent_sleep_time:  wakeup source阻止autosleep的总时间。
.event_count:  wakeup source上报wakeup event的个数。
.active_count: wakeup source处于active状态的次数。
.relax_count:  wakeup source处于deactive状态的次数。
.expire_count:  wakeup source timeout次数。
.wakeup_count:  wakeup source abort睡眠的次数。
.active:  wakeup source的状态。
.autosleep_enabled:  autosleep使能的状态。

Linux电源管理-wakeup events framework