Availability of XO-1.5 ATest-2 machines

Paul Fox pgf at laptop.org
Mon Jul 20 15:27:53 EDT 2009

david at lang.hm wrote:
 > On Mon, 20 Jul 2009, Paul Fox wrote:
 > > chris wrote:
 > > > Hi,
 > > >
 > > >    > my understanding from watching discussions here was that when the
 > > >    > system went to sleep it powered down the display, because there
 > > >    > was no way to set a timer to wake the system up a little later to
 > > >    > then turn off the display.
 > > >
 > > > Your understanding is incorrect, I'm afraid.  We do not power down the
 > > > display going into idle-suspend.
 > > >
 > >
 > > but to be clear, david's right that once the laptop's in this
 > > state there's no way to turn off the screen automatically later
 > > on -- the system must be re-awakened with user input, and then
 > > put to sleep in one of the usual (power switch or lid) ways.
 > > this is simply a limitation of current s/w.
 > is this just a software limitation? from the prior discussion I was under 


 > the impression that there was no timer that kept running once the main 
 > board goes to sleep, so you can't program anything to wake you up later to 
 > turn more stuff off. (not a problem normally, because normal systems don't 
 > have displays that can continue to show something once the main board is 
 > off)

rtcwake works fine, for these purposes, in later builds (post-767,
because rtc wakeups weren't distinguishable in the earlier kernels).

powerd uses this mechanism to accomplish screen (and system)
shutdown after sleep.  (olpc-powerd is the alternate power
management package i wrote while i had some <cough> downtime from
OLPC earlier this year.)

 paul fox, pgf at laptop.org

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