Linux vs. Windows Power Usage

Kpowersave does a good job of CPU throttling, but I've yet to see any tool for changing the screen brightness on Linux.

My batteries would be oh so much happier if I could.

odd, my function keys work just fine for my laptop regardless of distro.

I was thinking while reading that article though and the Helios Challenge came to mind. Knowing that the default installation of windows is incomplete, still needing spyware and virii detection software, plus a whole slew of other things just to get functional. It would be interesting to see what those tests would turn out after a few months of normal use.

We know that windows slows down over time, even for the meticulous disk defragger and cache purger. One has to wonder if the power consumption increases as well. Not knocking the phoronix guys, they have a record of being honest even if they don't like the results, just a curiosity. I for one though am not willing to sentence myself to windows just to answer that question.

I know the ibm t42 think pads have hardware keys that control the brightness. They work out of the box with zenwalk for me.

what model laptop are you using?

I'm facing the same problem. I have a laptop (Gateway Solo 1450) that has no hardware controls for screen brightness and contrast. You can adjust the brightness at the command line or in xorg.conf (something I'm probably going to do soon). In Xfce, you can go into the settings to adjust brightness and color saturation (if that's the correct term ...). I was surprised not to find a brightness GUI in GNOME.

Bob-- I'm using KDE 3.5.7 on Sabayon and I can indeed change the screen brightness with Kpowersave. It's not exactly user friendly, though.

If I'm using my laptop while unplugged, I right click on the Kpowersave icon, click Configure Kpowersave, and under Scheme Settings, click Powersave in the left hand column, and then click the Brightness tab. From that tab, I can adjust the brightness of my screen.

I'm new to the world of laptops, but I find with the low brightness, tickless kernel and a few other tricks gleaned by emerging and running Powertop, I get a lot of hours out of my laptop battery.

> I can indeed change the screen brightness with Kpowersave.

Good for you. Kpowersave reports "Screen does not support changing the brightness" or words to that effect, on three different laptops that I've put Linux on.

It is entirely a hardware problem, I know. The oldest has hardware-based buttons, so I can change the brightness by hand. Both the HP Pavilion and Sony Vaio have keys/buttons, but obviously only to signal Windows-based drivers. The sonypi and sony_laptop kernel modules have made no difference on the Vaio.

Bob--

Lesswatts.org says that X.org 7.3 contains a command line app called xbacklight that works in integrated Intel graphics cards "and others." Might be worth a shot. The site is owned by Intel, so the 'and others' comment might just be a bit of 'let's not mention the other video vendor(s)' reverse-propaganda.

They also describe 'echo'-ing a sysfs variable on older laptops that might also work, but apparently not as well.

http://www.lesswatts.org/tips/graphics.php