title: FLAG_TURN_SCREEN_ON does not always work
body: <p>i start an activity from a BroadcastReceiver, which is triggered by an alaram (RTC_WAKEUP type). in onCreate of that activity i add these flags</p>
  
  <pre><code>getWindow().addFlags(WindowManager.LayoutParams.FLAG_DISMISS_KEYGUARD |
      WindowManager.LayoutParams.FLAG_SHOW_WHEN_LOCKED |
      WindowManager.LayoutParams.FLAG_TURN_SCREEN_ON |
      WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON        
  );
  </code></pre>
  
  <p>problem is that sometimes (approximately 10% cases) the screen does not turn on. the alarm is correctly triggered (i here the sound of a notification, which is also fired in the receiver's onReceive(). then, if i hit the phone's power button, the screen turns on, showing my activity, and instantly turns off. after that, the power button works good. this happen on android 2.3.7 and here is the onReceive() method</p>
  
  <pre><code>@Override
  public void onReceive(Context context, Intent intent) {
      m_Context = context;
  
      Bundle extras = intent.getExtras();
      final int id = extras.getInt("timer_id");
  
      Intent activityIntent = new Intent(m_Context, MyActivity.class);
      activityIntent.putExtra("timer_id", id);
      activityIntent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_SINGLE_TOP);
      m_Context.startActivity(activityIntent);
  
      // and now load the alarm sound and play it for the desired time
      showFinishedNotification();
  }
  </code></pre>
  
  <p>i would like to avoid using PowerManager, as it needs a permission, and the flags are the prefered way.</p>
  
  <p>what could be a problem? logcat does not show any problems...</p>