I just installed a fresh copy of Ubuntu 12.04.3 LTS + Updates on a PC. I was forced to install it via the 'nomodeset' option, otherwise the screen would be filled with blinking graphical artifacts.
The problem now is: I wish to use the Open Source 'Radeon' driver, but my system boots directly into the Ubuntu 2D interface. I can't switch to normal Ubuntu. Somewhere on the internet I read that the free 'Radeon' driver should work by default out of the box, if it supports my GPU. I checked the list, and my GPU is supported by the driver.
My question therefor is: The proprietary driver works fine, but how do I safely activate the Open Source driver?
My GPU: Club 3D AMD HD 6570 1GB DDR3