cvs commit: src/sys/dev/acpica/Osd OsdSynch.csrc/sys/i386/include src/sys/amd64/include acpica_machdep.h

[Scott Long]

Mike Silbersack wrote:

> On Thu, 6 May 2004, Nate Lawson wrote:
> 
> 
>>>Does devd receive lid status events?  I'm thinking that it would be
>>>advantageous for my battery life if I could throttle the cpu down whenever
>>>the lid is closed.
>>
>>cat /etc/devd.conf:
>># Examples of notify hooks.  A notify is a generic way for a kernel
>># subsystem to send event notification to userland.
>>
>>If you want to change CPU idle states and/or throttling on AC line
>>transition, see the appropriate values in /etc/rc.conf.  But for one-offs
>>like lid to control CPU, using devd.conf and a small script is the way to
>>go.
>>
>>-Nate
> 
> 
> Good deal, it works as avertised.  I even learned a bit of shell scripting
> in the process of writing a simple speed switching script. :)
> 
> Of course, the real question is whether or not it'll actually help battery
> life at all; this is a mobile celeron, I suspect that I won't have much of
> an impact.  Ah well.
> 
> Mike "Silby" Silbersack

I've found that the best way to extend battery life on a laptop is to 
turn down the display brightness as low as possible.  CPU throttling,
PCI power states, etc, make a small (but measurable) difference on my
P4-M laptop, but the real win comes from turning down the brightness.

Scott