Fighting for the power.

[Dmitry Kolosov]

On Понедельник 04 мая 2009 07:45:09 Alexander Motin wrote:
> Adam McDougall wrote:
> > On Mon, May 04, 2009 at 01:18:14AM +0300, Alexander Motin wrote:
> > 
> >   I would like to summarize some of my knowledge on reducing FreeBSD power
> >   consumption and describe some new things I have recently implemented in
> >   8-CURRENT. The main character of this story is my 12" Acer TravelMate
> >   6292 laptop with C2D T7700 2.4GHz CPU, 965GM chipset and SATA HDD, under
> >   amd64 8-CURRENT.
> >   
> > Great list!  May I suggest screen brightness and DPMS as another tool
> > to save power, I've measured a 5W difference from the screen draw.
> > Keeping the brightness as low as tolerable helps considerably, but 
> > also using 'xset dpms 120 120 120' (modify to taste) in .xinitrc to
> > turn off the screen after 2 minutes helps when the laptop isn't being
> > used every second.  May need this in xorg.conf:
> > Option             "dpms"
> 
> Yes, backlight is also important. But there is not so much things could 
> be done.
> 
> When I am leaving system for some time, I can just close the lid, if not 
> put system into S3 state, which require very small power (at least I was 
> unable to really measure it without all-day-long testing). Thanks to 
> jkim@ we have more or less working S3 state for amd64 now.
> 
I'm using sysctl to controll brightness of my lcd (wrongly marked as crt by sysctl, but it works fine):
hw.acpi.video.crt1.brightness: 95 - current brightness of lcd (crt)
hw.acpi.video.crt1.fullpower: 95 - top level of brightness set by acpi_video if AC plugged
hw.acpi.video.crt1.economy: 43 - bottom level of brightness set by acpi_video if AC unplugged
hw.acpi.video.crt1.levels: 95 43 20 24 28 32 37 43 50 59 69 81 95 - various brightness levels can be set manual by sysctl

It works fine for me, and it's easy to write a script to react on different events during a day.