On Thu, 5 Aug 2010, Brian Swetland wrote: > On Thu, Aug 5, 2010 at 4:03 PM, Paul E. McKenney > <paulmck@xxxxxxxxxxxxxxxxxx> wrote: >>>> so what would wake a phone up from suspend where the phone should go back to >>>> sleep in under a second? >>> >>> Here are some real-world examples from shipped android devices: >>> - battery gauging happens every 10 minutes, need to wake long enough >>> to chatter with the 1w interface and make sure the battery is not >>> exploding >>> - always on mail/im/calendar/etc sync often has network events that >>> happen every 5-10 minutes which cause devices to briefly wake up and >>> return to sleep >>> - gps tracker app might wake every couple minutes or every n gps >>> events to log location >>> - low power audio subsystems can wake you up every 1-4 seconds (pcm) >>> or 1-4 minutes (mp3) to fetch more data >> >> Interesting! >> >> So for an mp3 playback, does an Android suspend between data fetches? > > It can if the latency is long enough (which is why I point out low > power audio which is usually high latency). For low latency (system > sounds, etc) 10-25ms between buffers it's not practical to fully > suspend but we will go to the lowest power state in idle if possible. the playback is able to continue even with all the clocks stopped? that surprises me. I would hav expected it to be able to sleep while playing audio, but not do a full suspend. David Lang _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
