转载地址:http://blog.csdn.net/shadow_dance/article/details/8070252
一. 屏幕的唤醒
首先inputread在读取到有keyboard事件上报后,会调用到keydispatch的notifykey,去询问wm是否会对这次按键特殊处理,如果WM不处理,则此处会点亮或者熄灭屏幕。
inputReader.cpp KeyboardInputMapper::processKey
getDispatcher()->notifyKey
inputDispacher.cpp InputDispatcher::notifyKey
mPolicy->interceptKeyBeforeQueueing
com_android_server_inputManager.cpp NativeInputManager::interceptKeyBeforeQueueing
env->CallIntMethod(mCallbacksObj,
gCallbacksClassInfo.interceptKeyBeforeQueueing,
when, action, flags, keyCode, scanCode, policyFlags, isScreenOn); //此处gCallbacksClassInfo中的各种方法就是InputManager的对应的方法,在JNI初始化的时候就注册了,详情请参看register_android_server_InputManager函数,通过jniRegisterNativeMethods将inputmanager的各种callback注册到gCallbacksClassInfo中。
返回的wmaction就是后面WM对此次按键事件的policy,通过此返回值,此处会决定下一步的动作。
InputManager.java interceptKeyBeforeQueueing
mWindowManagerService.mInputMonitor.interceptKeyBeforeQueueing
WindowmanagerService.java InputMonitor::interceptKeyBeforeQueueing
mPolicy.interceptKeyBeforeQueueing
PhonewindowManager.java interceptKeyBeforeQueueing
//摘录部分代码:
public int interceptKeyBeforeQueueing(long whenNanos, int action, int flags,
int keyCode, int scanCode, int policyFlags, boolean isScreenOn) {
final boolean down = action == KeyEvent.ACTION_DOWN;
final boolean canceled = (flags & KeyEvent.FLAG_CANCELED) != 0;
final boolean isInjected = (policyFlags & WindowManagerPolicy.FLAG_INJECTED) != 0;
// If screen is off then we treat the case where the keyguard is open but hidden
// the same as if it were open and in front.
// This will prevent any keys other than the power button from waking the screen
// when the keyguard is hidden by another activity.
final boolean keyguardActive = (isScreenOn ?
mKeyguardMediator.isShowingAndNotHidden() :
mKeyguardMediator.isShowing());
int result; //result即为返回到wmaction
if (isScreenOn || isInjected) {
// When the screen is on or if the key is injected pass the key to the application.
result = ACTION_PASS_TO_USER;
} else {//我们现在走的应该是这个
// When the screen is off and the key is not injected, determine whether
// to wake the device but don't pass the key to the application.
result = 0;
final boolean isWakeKey = (policyFlags
& (WindowManagerPolicy.FLAG_WAKE | WindowManagerPolicy.FLAG_WAKE_DROPPED)) != 0;
if (down && isWakeKey) {
if (keyguardActive) {
//也就是说,如果当前屏幕是灭的,且按的键是可以唤醒屏幕的,那么WM会首先将此次按键传递给keyguard,由keyguard来唤醒屏幕,并作出相应的动作,否则就自己点亮屏幕,通过返回的policy来通知下层。 // If the keyguard is showing, let it decide what to do with the wake key. mKeyguardMediator.onWakeKeyWhenKeyguardShowingTq(keyCode); } else { // Otherwise, wake the device ourselves. result |= ACTION_POKE_USER_ACTIVITY; } } } .................... }keyguarViewMediator.java onWakeKeyWhenKeyguardShowingTq
wakeWhenReadyLocked
mHandler.obtainMessage(WAKE_WHEN_READY, keyCode, 0);
mHandler.handleMessage
handleWakeWhenReady
mKeyguardViewManager.wakeWhenReadyTq
KeyguardViewManager.java mKeyguardView.wakeWhenReadyTq
LockpatternKeyguardView.java wakeWhenReadyTq
getCallback().pokeWakelock();
KeyguardViewMediator.java pokeWakelock
mWakeLock.acquire(); // mWakeLock即为:mWakeLock = mPM.newWakeLock(
PowerManager.FULL_WAKE_LOCK | PowerManager.ACQUIRE_CAUSES_WAKEUP,
"keyguard"); 具有ACQUIRE_CAUSE_WAKUPQ权限的唤醒锁,上层就是通过此锁来唤醒屏幕,接下来就是powermanager的流程了。
PowerManager.java acquire
mService.acquireWakeLock
PowermanagerService.java acquireWakeLock
acquireWakeLockLocked//此处会检查唤醒锁的标志位,作出对应的处理。
setPowerState //此函数为powermanager的核心函数之一,会对屏幕背光/唤醒,睡眠等作出相应的处理
setScreenStateLocked //此函数很关键
Power.setScreenState
power.java setScreenState
android_os_Power.cpp setScreenState
power.c set_screen_state//此函数作为上层的最后一个函数,会打印出标志性的log,*** set_screen_state %d,如果打出这个log,至少证明从APP-HAL都是在正常干活的,那么问题只能是kernel的了,贴出代码看看:
int
set_screen_state(int on)
{
//QEMU_FALLBACK(set_screen_state(on));
LOGI("*** set_screen_state %d", on); //神奇的log标志
initialize_fds();
//LOGI("go_to_sleep eventTime=%lld now=%lld g_error=%s\n", eventTime,
// systemTime(), strerror(g_error));
if (g_error) return g_error;
char buf[32];
int len;
if(on)
len = sprintf(buf, "%s", on_state);
else
len = sprintf(buf, "%s", off_state);
len = write(g_fds[REQUEST_STATE], buf, len);//此处就是写了kernel的设备文件接口。
if(len < 0) {
LOGE("Failed setting last user activity: g_error=%d\n", g_error);
}
return 0;
}
在此函数中写了底层的power控制的设备文件接口,对应的设备文件为:/sys/power/state
接下来的流程就是到了内核空间。
kernel/kernel/power/main.c state_store
//此函数被宏power_attr(state)声明为设备文件接口 sys/power/state,宏power_attr的定义为(power.h):
#define power_attr(_name) \
static struct kobj_attribute _name##_attr = {\
.attr = {\
.name = __stringify(_name),\
.mode = 0644, \
}, \
.show = _name##_show,\
.store = _name##_store, \
}
static ssize_t state_store(struct kobject *kobj, struct kobj_attribute *attr, const char *buf, size_t n) { #ifdef CONFIG_SUSPEND #ifdef CONFIG_EARLYSUSPEND suspend_state_t state = PM_SUSPEND_ON; #else suspend_state_t state = PM_SUSPEND_STANDBY; #endif const char * const *s; #endif char *p; int len; int error = -EINVAL; p = memchr(buf, '\n', n); len = p ? p - buf : n; /* First, check if we are requested to hibernate */ if (len == 4 && !strncmp(buf, "disk", len)) { error = hibernate(); goto Exit; } #ifdef CONFIG_SUSPEND for (s = &pm_states[state]; state < PM_SUSPEND_MAX; s++, state++) { if (*s && len == strlen(*s) && !strncmp(buf, *s, len)) break; } printk("##: enter %s\n", pm_states[state]); if (state < PM_SUSPEND_MAX && *s) #ifdef CONFIG_EARLYSUSPEND // android对linux的睡眠唤醒机制做了一些优化,也就是earlysuspen,laterresume机制,此处宏是有定义的,所以会先走android的那一套 if (state == PM_SUSPEND_ON || valid_state(state)) { error = 0; printk("##: entering request_suspend_state()...\n"); request_suspend_state(state); } #else error = enter_state(state); #endif #endif Exit: printk("##: state_store() returns back.\n"); return error ? error : n; }
kernel/kernel/power/erlysuspend.c request_suspend_state
void request_suspend_state(suspend_state_t new_state) { unsigned long irqflags; int old_sleep; /* when we get here, means userspace service work well, stop reboot watchdog */ powerkey_wdt_stop(); spin_lock_irqsave(&state_lock, irqflags); old_sleep = state & SUSPEND_REQUESTED; if (debug_mask & DEBUG_USER_STATE) { struct timespec ts; struct rtc_time tm; getnstimeofday(&ts); rtc_time_to_tm(ts.tv_sec, &tm); pr_info("request_suspend_state: %s (%d->%d) at %lld " "(%d-%02d-%02d %02d:%02d:%02d.%09lu UTC)\n", new_state != PM_SUSPEND_ON ? "sleep" : "wakeup", requested_suspend_state, new_state, ktime_to_ns(ktime_get()), tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday, tm.tm_hour, tm.tm_min, tm.tm_sec, ts.tv_nsec); } if (!old_sleep && new_state != PM_SUSPEND_ON) { state |= SUSPEND_REQUESTED; queue_work(suspend_work_queue, &early_suspend_work); } else if (old_sleep && new_state == PM_SUSPEND_ON) { state &= ~SUSPEND_REQUESTED; wake_lock(&main_wake_lock); //acquire main ——wakelock queue_work(suspend_work_queue, &late_resume_work); //将唤醒的work起来,开始执行之前声明的late_resume_work } requested_suspend_state = new_state; spin_unlock_irqrestore(&state_lock, irqflags); }而 之前有声明static DECLARE_WORK(late_resume_work, late_resume); 故实际执行的函数是:late_resume。
kernel/kernel/power/erlysuspend.c late_resume
static void late_resume(struct work_struct *work) { struct early_suspend *pos; unsigned long irqflags; int abort = 0; mutex_lock(&early_suspend_lock); spin_lock_irqsave(&state_lock, irqflags); if (state == SUSPENDED) state &= ~SUSPENDED; else abort = 1; spin_unlock_irqrestore(&state_lock, irqflags); if (abort) { if (debug_mask & DEBUG_SUSPEND) pr_info("late_resume: abort, state %d\n", state); goto abort; } if (debug_mask & DEBUG_SUSPEND) pr_info("late_resume: call handlers\n"); list_for_each_entry_reverse(pos, &early_suspend_handlers, link) if (pos->resume != NULL) { print_name_offset(NULL, pos->resume); pos->resume(pos); //此处会调用到之前注册了laterresume的drv的对应的函数,调用到fb_resume之后,屏幕就唤醒刷屏,屏幕上夜就有了数据,屏幕唤醒的流程就结束了。 } if (debug_mask & DEBUG_SUSPEND) pr_info("late_resume: done\n"); abort: mutex_unlock(&early_suspend_lock); }
二、 屏幕睡眠
和屏幕唤醒的过程很类似,如下:
inputReader.cpp KeyboardInputMapper::processKey
getDispatcher()->notifyKey
inputDispacher.cpp InputDispatcher::notifyKey
mPolicy->interceptKeyBeforeQueueing
com_android_server_inputManager.cpp NativeInputManager::interceptKeyBeforeQueueing
InputManager.java interceptKeyBeforeQueueing
mWindowManagerService.mInputMonitor.interceptKeyBeforeQueueing
WindowmanagerService.java InputMonitor::interceptKeyBeforeQueueing
mPolicy.interceptKeyBeforeQueueing
PhonewindowManager.java interceptKeyBeforeQueueing
//同上面的分析,此处返回的action是被或上了ACTION_GO_TO_SLEEP的(见1975行对KeyEvent.KEYCODE_POWER的处理).......一级一级的返回后.....com_android_server_inputManager.cpp NativeInputManager::interceptKeyBeforeQueueing //返回值中含有gotosleep的flag,故走到gotosleep分支
android_server_PowerManagerService_goToSleep
com_android_server_PowerManagerService.cpp android_server_PowerManagerService_goToSleep //同上面的inputmanager,此处也会调用到PowerManagerService的gotosleep,也是用register_android_server_PowerManagerService方法来对应起来。
env->CallVoidMethod(gPowerManagerServiceObj, gPowerManagerServiceClassInfo.goToSleep,
nanoseconds_to_milliseconds(eventTime));
PowermanagerService.java goToSleep
goToSleepWithReason
goToSleepLocked
setPowerState(SCREEN_OFF, false, reason);
setPowerState
setScreenStateLocked
Power.setScreenState(false)
power.java setScreenState
android_os_power.java setScreenState
power.c set_screen_state
kernel/kernel/power/main.c state_store
kernel/kernel/power/earlysuspend.c request_suspend_state //此处流程和唤醒大同小异,不在赘述
early_suspend
static void early_suspend(struct work_struct *work)
{
struct early_suspend *pos;
unsigned long irqflags;
int abort = 0;
mutex_lock(&early_suspend_lock);
spin_lock_irqsave(&state_lock, irqflags);
if (state == SUSPEND_REQUESTED)
state |= SUSPENDED;
else
abort = 1;
spin_unlock_irqrestore(&state_lock, irqflags);
if (abort) {
if (debug_mask & DEBUG_SUSPEND)
pr_info("early_suspend: abort, state %d\n", state);
mutex_unlock(&early_suspend_lock);
goto abort;
}
if (debug_mask & DEBUG_SUSPEND)
pr_info("early_suspend: call handlers\n");
list_for_each_entry(pos, &early_suspend_handlers, link) {
if (pos->suspend != NULL) {
print_name_offset(NULL, pos->suspend);
pos->suspend(pos); //调用注册了earlysuspend的drv的suspend函数,调用到了fb_suspend,屏幕就会进入睡眠,睡眠的过程就结束了
}
}
mutex_unlock(&early_suspend_lock);
if (debug_mask & DEBUG_SUSPEND)
pr_info("early_suspend: sync\n");
//sys_sync();//let screen up faster
abort:
spin_lock_irqsave(&state_lock, irqflags);
if (state == SUSPEND_REQUESTED_AND_SUSPENDED)
wake_unlock(&main_wake_lock); //earlysuspend完毕后,检查当前是否还有wakelock是active状态,如果没有,则会进入深睡眠(linux的suspend)
spin_unlock_irqrestore(&state_lock, irqflags);
}
kernel/kernel/power/wakelock.c wake_unlock
void wake_unlock(struct wake_lock *lock) { int type; unsigned long irqflags; spin_lock_irqsave(&list_lock, irqflags); type = lock->flags & WAKE_LOCK_TYPE_MASK; #ifdef CONFIG_WAKELOCK_STAT wake_unlock_stat_locked(lock, 0); #endif if (debug_mask & DEBUG_WAKE_LOCK) pr_info("wake_unlock: %s\n", lock->name); lock->flags &= ~(WAKE_LOCK_ACTIVE | WAKE_LOCK_AUTO_EXPIRE); list_del(&lock->link); list_add(&lock->link, &inactive_locks); if (type == WAKE_LOCK_SUSPEND) { long has_lock = has_wake_lock_locked(type); //判断当前是否还有wake_lock是active的 if (has_lock > 0) { if (debug_mask & DEBUG_EXPIRE) pr_info("wake_unlock: %s, start expire timer, " "%ld\n", lock->name, has_lock); mod_timer(&expire_timer, jiffies + has_lock); } else { if (del_timer(&expire_timer)) if (debug_mask & DEBUG_EXPIRE) pr_info("wake_unlock: %s, stop expire " "timer\n", lock->name); if (has_lock == 0) { if (sprd_suspend_enable) { queue_work(suspend_work_queue, &suspend_work); //起suspend_work,根据声明,此处的work对应的函数即是suspend } } } if (lock == &main_wake_lock) { if (debug_mask & DEBUG_SUSPEND) print_active_locks(WAKE_LOCK_SUSPEND); #ifdef CONFIG_WAKELOCK_STAT update_sleep_wait_stats_locked(0); #endif } } spin_unlock_irqrestore(&list_lock, irqflags); }
static void suspend(struct work_struct *work) { int ret; int entry_event_num; add_pm_message(get_sys_cnt(), "suspend--enter: ", 0, 0, 0); if (has_wake_lock(WAKE_LOCK_SUSPEND)) { if (debug_mask & DEBUG_SUSPEND) pr_info("suspend: abort suspend\n"); return; } entry_event_num = current_event_num; sys_sync(); if (debug_mask & DEBUG_SUSPEND) pr_info("suspend: enter suspend\n"); ret = pm_suspend(requested_suspend_state); if (debug_mask & DEBUG_EXIT_SUSPEND) { struct timespec ts; struct rtc_time tm; getnstimeofday(&ts); rtc_time_to_tm(ts.tv_sec, &tm); pr_info("suspend: exit suspend, ret = %d " "(%d-%02d-%02d %02d:%02d:%02d.%09lu UTC)\n", ret, tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday, tm.tm_hour, tm.tm_min, tm.tm_sec, ts.tv_nsec); } if (current_event_num == entry_event_num) { if (debug_mask & DEBUG_SUSPEND) pr_info("suspend: pm_suspend returned with no event\n"); wake_lock_timeout(&unknown_wakeup, HZ / 2); } add_pm_message(get_sys_cnt(), "suspend--leave: ", 0, 0, 0); }
int pm_suspend(suspend_state_t state) { if (state > PM_SUSPEND_ON && state <= PM_SUSPEND_MAX) return enter_state(state); //是不是和main.c里的state_store函数中liunx的suspend一样?豁然开朗。 return -EINVAL; }
接下来就是linux的suspend了,没有再仔细看过,惭愧惭愧。
总的来说,屏幕的睡眠是和上层的keyguard没有关系,是在WM和PMS以及相关的JNI的配合下对kernel的操作完成的。
屏幕唤醒和睡眠就写到这里,而背光的点亮过程,大部分处理是在PMS中,是在HAL层操作了lights的设备文件并不涉及到唤醒和睡眠,显得比较简单,有时间也写出来分享。