XFCE Laptop Display Brightness Adjustment Failure - Quick Fix by eokuwwy
Note: I am running Debian Squeeze (stable) kernel 2.6.32-5-amd64
Adjusting the brightness of your display is something that you would expect to “just work.” However, a google search (of which I have done a few thousand times tonight) will show that many people have issues with this on Linux systems, especially with XFCE. In some cases, it’s a simple issue of having messed up keybindings, and if that is the case, then great. That can be solved without too much hassle. But if it’s a device problem, kernel problem, or driver problem, or any combination of those, you might end up being OOTBAITF.
Thankfully, there’s always someone who finds a quick fix. http://askubuntu.com/questions/25244/how-to-handle-brightness-trouble-on-dell-inspiron-i14r-2265
Here’s what I did:
- sudo apt-get install xcalib
- Menu→Settings→Keyboard→Application Shortcuts
- Click the Add button
- Type in /usr/bin/xcalib -co 90 -a and press enter
- Press the brightness DOWN key on your keyboard, or if it is a sequence, type the sequence (i.e., Fn + F4)
- Click the Add button
- Type in /usr/bin/xcalib -c and press enter
- Press the brightness UP key on your keyboard, or if it is a sequence, type the sequence (i.e., Fn + F5)
Now if I could get my damn fonts to look right. Everything is blurry!
NERD NOTICE:(Added 12-03-2011)
Since we are adjusting the brightness by percentage, the decrease is not linear. Assuming that the screen will appear completely dark and visually featureless (to the human eye) at 1% of its full brightness level, we can determine the number of “brightness-down” key-shortcut presses that it will take to make the screen completely dark and devoid of features with the following equation:
100*.9^n=1
Plugging that into wolframalpha, you’ll see that the solution is approximately 43.7087. And indeed, after about 40 presses of the brightness-down keyboard shortcut, it will appear to be completely dark and devoid of any features.
So, can you ever get to COMPLETE darkness? Mathematically, the answer is no, because reaching 0 can only be defined as the limit of the function as n goes to infinity:
lim 100*.9^n as n→Infinity = 0.
100*.9^n = 0 has no solutions, so you’ll never make it to the pure abyss! Fortunately xcalib has a lower limit of 1.0, so after 43 times, you won’t be able to go any further.
:p
PS: You can use that same initial equation to adjust your percentage drop and see how long it will take to reach total darkness. The initial example I found was:
xcalib -co 60 -a
So you can simply change the initial equation to:
100*.6^n = 1
Again, using wolfram alpha, you’ll see that you’ll reach the bottom at 9 presses. More importantly though, after only two presses, the screen brightness is already down to under 40%. That’s too steep of a drop for me, which is why I use 90%. For me it’s more like turning a knob. At 60%, it’s more like flipping a switch.