xfce4-power-manager 0.6.0 beta1 released

[Kok, Auke]

Liviu Andronic wrote:
> On Mon, Oct 27, 2008 at 12:53 AM, Ali Abdallah <ali.slackware at gmail.com> wrote:
>> I just released a beta1 version 0.6.0 of the Power Manager.
>>
> http://goodies.xfce.org/projects/applications/xfce4-power-manager
> 
> Liviu

I haven't tested this yet but I wanted to provide some general insights on this as
part of my job is to look over power management (I'm the current powertop
maintainer for instance).

reading on the goodies webpage:

--This software is a power manager for the Xfce desktop, laptop users can set up a
power profile for two different modes “on battery power” and “on ac power”,
desktop users still can change DPMS settings and CPU frequency using the settings
dialog. --

these are all the wrong things, and you shouldn't write a power manager that works
in this way at all.

The notion that "on battery power" is something different as "on AC power" is
bogus. Saving power needs to happen in both cases. It lowers your electrical bill,
cooling needed (which results in even less power used overall in your home) and is
good for the environment. Power saving does not stop when you plug in your computer.

Likewise, the computer should always run in ondemand governor. Never ever does the
user themselves need to select a different governor since the kernel knows best
what speed is needed for the current workload. In my 5-second boot project, we
showed that the computer starts up exactly in the same speed with both ondemand
and performance governors. We should really not let the user make things worse,
especially when the kernel does such a great job and knows best.


For instance, in the classical world you would have your screen become less bright
when you unplug your power cable. But if you are sitting in a sunlit airport
terminal or are showing your presentation to a colleague in a cafe, or are playing
a movie on the couch at home or in an airplane, you'd want the brightness to be
high so you can enjoy actually seeing the details on screen. So therefore it's the
application running (movie player, presentation) or the environment (lots of
peripheral light) that dictates the screen brightness, not the presence of AC power.

The same notion happens with screen blanking. Does it not stink to have to touch
your mouse every 5 minutes in order to prevent the screen from blanking when you
watch a movie?

Now of course, a lot of this application-dependent code hasn't been written yet or
the driver support is lacking. There's surely a lot of work to be done and I'm not
saying that this needs to come from the Xfce goodies people (on the contrary).

Having GUI accessible dpms settings of course is a nice thing. That in itself
could be an application on it's own...



Auke