On Thu, Aug 5, 2010 at 10:46 AM, <firstname.lastname@example.org> wrote:
IIRC, this was a major point of their (Android's) power management
policy. User input of any kind would reset the "display active"
timeout, which is the primary thing keeping random untrusted
user-facing programs from being suspended while in use. They seemed
to consider this to be a special case in their policy, but from the
kernel's point of view it is just another suspend blocker being held.
I'm not sure this is the best use case to look at though, because
since it is user-facing, the timeout durations are on a different
scale than the ones they are really worried about. I think another
category of use case that they are worried about is:
(in suspend) -> wakeup due to network -> process network activity -> suspend
or an example that has been mentioned previously:
(in suspend) -> wakeup due to alarm for audio processing -> process
batch of audio -> suspend
In both of these cases, the display may never power on (phone might
beep to indicate txt message or email, audio just keeps playing), so
the magnitude of the "timeout" for suspending again should be very
small. Specifically, they don't want there to be a timeout at all, so
as little time as possible time is spent out of suspend in addition to
the time required to handle the event that caused wakeup.