Android(ICS) frequently wakes up from sleep -

why android( ics ) keep waking sleep ? using serial connection board monitor kernel prints, can see every , android wakes , goes sleep. because of scheduled task or something? how can prevent happening?

thanks

is because of scheduled task or something?

quite possibly. adb shell dumpsys alarm show events scheduled via alarmmanager. "wakeup" events wake device out of sleep mode.

incoming data packets on open socket on mobile data, incoming phone calls, , incoming sms messages wake android device out of sleep mode.

how can prevent happening?

if app waking device, presumably can change app avoid it.

if third-party app installed waking device, uninstall app.

beyond that, way control via own rom mod, alter behavior of os such wakeup alarms not wake device. complex bit of work in general, let alone right.

or, switch device has such capability built in. example, of sony xperia line, such sony xperia z, offer "stamina mode" can block wakeup alarms waking device. cover installed apps; may not affect wakeups os components, if sony believed essential.

or, don't worry waking up, or modify things on other end of serial connection not worry waking up.