Power manager specification... (request for comments).

Jim Gettys jg at laptop.org
Thu Aug 16 09:57:02 EDT 2007

On Thu, 2007-08-16 at 07:23 +0800, Yuan Chao wrote:

> > o On momentary power button:
> >   turn off screen, suspend machine, leave keyboard and wireless on;
> > keyboard/touchpad will cause instant on again.
> I'm curious here that I thought the wireless needs CPU to work with.
> Why suspend the machine and leave the wireless on?

No, our wireless is able to forward packets in the mesh network without
the main CPU being powered.  It is important for people to easily leave
their machine in a mode which maintains the mesh network for others in
the network.

> > o on lid close, on power, leave the machine on and running.
> Even though it's on AC power, maybe the screen can also be turned off
> to be more Eco?

Yup.  It certainly should be.

> > o On ebook mode, should turn off keyboard
> > o On lid open, should reset keyboard
> There seems to be no way to manually adjust the backlight level in
> ebook mode. What would be the policy for it? Leave it on all the time
> or dim down after some idle time? Also CPU (and wireless?) should go
> to suspend for most of time in ebook mode?

We have code in at least our PDF viewer to literally do exactly this; as
soon as the page is rendered and it is idle, it puts the machine to

> > o rotate should probably be done by OHM.
> There seems no way to predict which direction to go in ebook mode as
> no position sensor. Here you mean restore the rotation after get back
> from ebook mode?

No, mostly that we happened to first implement this in Sugar, and it is
really much more a hardware and window manager function from a
architectural perspective.
                                            - Jim

Jim Gettys
One Laptop Per Child

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