On Jan 25, 12:33 am, Paul Marks <pma...@google.com> wrote: > I'm currently writing an app that uses a Service. A thread in the > service generates an infinite stream of audio, and writes it to > theAudioTrack. I want the audio to keep playing indefinitely until the > user stops it. > > Based on my understanding of the PowerManager class, it looks like I > should need a PARTIAL_WAKE_LOCK to keep the CPU awake so the audio can > continue playing. > > However, I left the audio playing on my phone with no wake lock, > running on battery, in airplane mode, with all five items on the power > control widget disabled, and the audio just kept right on playing for > at least 15 minutes. Afterwards, I looked at the battery history, and > it showed "Running (100%)", even though the Partial wake usage was > negligible. > > Is there something special about AudioTrackwhich prevents the CPU > from entering its deep sleep state? Should it be necessary for my > service to grab a PARTIAL_WAKE_LOCK and its associated permission?
After speaking with one of the developers, I learned: - On current platforms, the audio driver acquires its own wake lock, which explains why my phone was not going to sleep. http://android.git.kernel.org/?p=platform/hardware/msm7k.git;a=blob;f=libaudio-qsd8k/AudioHardware.cpp;hb=HEAD - There's no explicit guarantee that this will always be true for all platforms, so it's still a good idea to hold a PARTIAL_WAKE_LOCK if you need to stay awake while using an AudioTrack. -- You received this message because you are subscribed to the Google Groups "Android Developers" group. To post to this group, send email to android-developers@googlegroups.com To unsubscribe from this group, send email to android-developers+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/android-developers?hl=en
