Re: [RFC] dynamic device power management proposal

[Jim Gettys <jg@laptop.org>]

On Thu, 2007-03-22 at 00:42 -0400, Len Brown wrote:

> Today on system suspend we suspend all devices.
> Today on system resume, we resume all devices.
> In the future we need to recognize that upon system suspend,
> some devices are already suspended.
> We need to remember that, so upon resume we can restove
> them to their suspended state, rather than blindly resuming everything.

On system suspend, we may not want to suspend all devices; we may need
to leave certain devices alone, and only power down the host interface
to them.

Upon system resume, therefore, devices may also *not* need to be
resumed; only the host interface to them powered up again.

We have two devices in the OLPC machine in this class: our screen, and
our wireless, both of which will often/usually be left on while the rest
of the sysetm is suspended.
                                          - Jim


-- 
Jim Gettys
One Laptop Per Child