acpi

[David Zeuthen]

On Wed, 2006-08-02 at 17:03 +0100, Andy Green wrote:
> Just an idea -- on this laptop at least the ACPI reports the current 
> being drawn from the battery with good resolution, eg, when plugged in 
> and charged

You can also just use gnome-power-manager - right click on the icon in
the notification area and select "Information", then "Power History".

It looks somewhat like this

 http://www.hughsie.com/applications/Coppermine/displayimage.php?album=9&pos=9

Using this tool I learned that

 - The difference from LCD max/min brightness is a ~1-2 watts on my IBM
   Thinkpad T41 - which is ~ 10% of the power drain

 - Powering down the disk via hdparm and using laptop-mode in the kernel
   also saves ~ 1W - another ~ 100% 
   (unfortunately the IDE layer in the kernel don't really support power
    management yet and it's too dangerous / error prone to use hdparm
    by default in the distro)

There's a bunch of other things related to run-time power management
that is going on in the kernel right now and it looks pretty good so
far.

HTH,
David