Help WiFi doesn't sleep when screen is off, draining battery.

[ninsei]

Hi. I'm on 2.3.4. I have my WiFi policy set to sleep when screen is off. but it doesn't (I can still ping it). I looked into this cause, after a full charge at night, I tap the power button (screen goes off), after ~8 hours, my battery is near dead, I have just enough time to check battery stats: display is 65%, Wifi is 16%, and phone idle is 8%.