announce: alternate power management

pgf at pgf at
Fri Mar 20 09:07:57 EDT 2009

albert wrote:
 > pgf writes:
 > > so:  i've packaged a new version of powerd.  the big change
 > > is that it now allows for the two modes of operation i mentioned
 > > last week on the list:
 > >                 dim
 > >                 sleep, screen on
 > >                 sleep, screen off
 > >                 shutdown
 > > or:
 > >                 dim
 > >                 screen off
 > >                 sleep, screen off
 > >                 shutdown
 > "screen on" and "screen off" aren't very well defined.
 > What exactly do you mean?

sorry -- i was describing it from a naive user's perspective.  here:

     dim		(reduced backlight)
     sleep, screen on	(cpu sleep, dcon on, backlight still on and dim)
     sleep, screen off  (cpu sleep, dcon off, backlight off)
     dim		(reduced backlight)
     screen off		(cpu running, dcon off, backlight off)
     sleep, screen off  (cpu sleep, dcon off, backlight off)

the two cases are diffentiated by powerd simply by looking at
the middle two timers -- if the timer for sleeping is smaller than
the timer for turning hte screen off, you get the first set of
steps, otherwise the second.

(btw, probably obvious, but any trailing subset of these steps
can be supressed simply by setting the appropriate timeout
arbitrarily high.)

 > a. the Geode chipset: producing video or not?
i don't believe anything explicit for this is done (except
shutdown and cpu sleep, of course).  i'm not sure how to
accomplish this.

 > b. the DCON: pass-through, freeze-frame, or off?
the dcon is frozen while the shutdown splash screen(s) are
painting, so that you can't see the shades coming down.  other
than that, it remains unfrozen, but is turned on and off as noted

 > c. the backlight: on or off?
turned on and off as above.  when dimming, the level being ramped
to is configurable, so if you set it to 15, no dimming will occur.

 > d. the LCD panel: on or off?
i confess i don't know how to do that.  if it's feasible, and not
happening already, it should be added.

 paul fox, pgf at

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