本帖最后由 keer_zu 于 2020-4-2 11:15 编辑
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。
/**
* 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。
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