power management experiences with joyride-1572

[Chris Ball]

Hi,

   > What does "organized ahead of time" mean?

Setting a wakeup timer before going to sleep.

   > Can I wake up 10 seconds from now?  Is there a timer in any of the
   > hardware that is left running?

There are two timers left running.  There is the Geode southbridge RTC,
which can set a wakeup to one-second resolution (but not sub-second)
using the standard Linux RTC device interface.  There is also the EC,
which has just gained the same ability but without the limitation of
having to set wakeups on second boundaries.  I suspect that we will
start to use the EC timer in the next feature release of the software.

In the future, we can imagine setting wakeups programmatically, with
the help of the Linux dynamic ticks implementation and the cpuidle
framework -- if Frank's sugar clock has a pending wakeup in 60 seconds
to update the minute hand of the clock, we can set a wakeup for +59s
before going to sleep.  This is a long-term feature, though.

- Chris.
-- 
Chris Ball   <cjb at laptop.org>