How can I see which wakelocks are active

Question

For some reason my Android phone won\'t go to sleep. I assume that a wakelock is keeping it awake, but there is no way to tell which wakelocks are active. The running servic

Answer 1

Does Android definitely release wakelocks when a process ends?

I doubt it, though I do not know for certain.

Is it possible an app was badly written and didn't release a wakelock before exiting?

AFAIK, yes.

Is there any way to see the active wakelocks?

Run adb shell dumpsys power.

Answer 2

For what it's worth, on Android 7.1.1 this is exactly what I was looking for:

greatqlte:/ $ dumpsys power | grep WAKE_LOCK
  PARTIAL_WAKE_LOCK              'ES Wake Lock' ACQ=-38m52s804ms LONG (uid=10275 pid=12504)                                                                                                 
  PARTIAL_WAKE_LOCK              '*net_scheduler*' ACQ=-40ms (uid=10031 pid=3026 ws=Work Source{10031 com.google.android.gms})                                                               

Answer 3

You can use below adb command to require a wake lock

  adb shell "echo mylock > /sys/power/wake_lock"

Then, you can use below command to watch if this lock is active. You will see the time column continuously change, it means the wake lock is active

  watch -n 1 'adb shell "cat /proc/wakelocks" | grep mylock'

Now, use this adb command to release the wake lock

  adb shell "echo mylock > /sys/power/wake_unlock"

Then, check it again, the time column will freeze, it means the wake lock is non active

  watch -n 1 'adb shell "cat /proc/wakelocks" | grep mylock'

You can use the same technique to observe the wake lock you acquire in the code.

Answer 4

Android does not release wakelocks when the process ends. It should be explicitly released by the process before ending.

Answer 5

In new versions of Android you can see list of wakelocks here:

adb shell "cat /sys/kernel/debug/wakeup_sources"

Answer 6

As others have already said, adb shell dumpsys power can show you active wakelocks.

However, for apps that didn't release wakelock, as per the answer here: https://stackoverflow.com/a/16258624/428271 It should be released by Android. However, it is for case where app/process is killed, but it should be applicable when app/process is complete too. It also provides the source code references rather than just saying 'checked in code'