How to fix Linux automatic screen brightness adjustment

I’ve had this happen on a couple of my laptops now: you switch windows from a window containing a lot of text to, say, a browser window with images and you screen suddenly darkens or lightens, all of it’s own accord. Which can be cool, but also quite annoying.

The culprit is the fglrx driver you may have unwittingly installed.  If you have an ATI graphics card of recent vintage in your computer, you will likely have installed the proprietary graphics driver.  In Ubuntu this is easy to do after install; the system will often prompt you with the option.  In other distros, you may have just googled to solve the problems with your display or just have known that that was the driver to install for your computer.

Regardless, this is how to fix it:

In your settings menu you might find ATI Catalyst Control Center or, from the command line amdcccle is the command you want.

On the PowerPlay “page” you will see options to help you adjust the power consumption of your graphics card.  Uncheck the “Enable Vari-Bright(tm)” checkbox.

I hope this helps someone.  You might also have gotten here by searching for dynamic contrast on Linux or by trying to figure out why your monitor is automatically adjusting it’s own brightness. Well, here’s how to fix it! (That might be homegrown SEO, but I spent a while googling to try to figure this out and I hope to save others some time!)