cpu scaling questions

[David Zeuthen]

On Mon, 2006-10-02 at 20:43 -0400, Alan Cox wrote:
> No what I meant was if I set properties in GNOME and then exit X, or
> leave the laptop at gdm or in text mode to save power are the policy side
> of things still running.

The plan for Fedora for such (kinda obscure) use cases, I think, is to
run gnome-power-manager headless, some detail is here

 http://bugzilla.gnome.org/show_bug.cgi?id=356174

but it needs a little bit of experimenting as you can tell from the bug.
Notably we don't yet have any really good infrastructure for tracking
user sessions so it's difficult to manage life cycles of policy daemons.

So, once that is in place we'll put a "Set settings as system-wide"
button into g-p-m but that too requires some other infrastructure bits
(PolicyKit) that needs to be baked too. If only one user is on the
system (typical laptop use case) we might even set them as default
automatically. 

Anyway, we'll be able to give our other policy daemons the same
treatment, e.g. make g-v-m auto mount volumes, NM auto connect to
networks etc. This will be useful for data center use once g-v-m gains
the ability to automatically share removable media when hotplugged using
Avahi. E.g. the sysadmin plugs in media and it appears on the network
automatically.

The decision to recycle the desktop power management daemons for
(obscure) cases when no-one is logged in etc. is justified by 1) easy
configuration; 2) feature parity; and 3) code reuse.

> Ditto if I'm running Fedora + KDE or XFCE and have run the gnome tool to
> set the power policy ?

I expect that once KDE, XFCE or other desktops can provide functionality
to run policy daemons such as g-p-m equivalents headless nothing
prevents us from doing the same thing for them.

So, e.g. g-p-m should only run headless if gdm is the display manager,
the KDE equivalent should only run headless if kdm is the display
manager and so forth. Or we could look at the variable
in /etc/sysconfig/desktop. 

Hope this explains.

    David