If everything went well, the Avivo X.Org driver will have been installed. However, the xorg.conf needs to be manually updated to reflect the newly installed driver. After opening your xorg.conf in gedit or your favorite text editor, the driver in the graphics card's device section needs to be set to avivo (from vesa or fglrx).
sudo gedit /etc/X11/xorg.conf
At this time, you'll also need to add the following lines to the xorg.conf as well, to prevent errors when starting X since the Avivo driver doesn't currently support AIGLX.
Option "Composite" "Disable"
Option "AIGLX" "Off"
Chances are you'll want to enable Shadow Framebuffer support. Shadow Framebuffer allows rendering to be done in memory in the shadow framebuffer. Enabling this option can dramatically increase the performance of the Avivo driver and would be recommended. Add theShadowFB option to the device section in the xorg.conf where the avivo alteration was made.
Option "ShadowFB" "On"
After the xorg.conf has been updated, restart X.Org and you should be good to go with an open-source ATI Radeon X1000 display driver. Eventually, this driver will also support the Radeon HD 2000 series. The Avivo driver also works with RandR 1.2 for dynamic display support.
In the event you run into any problems with the Avivo driver, be sure to stop by the Phoronix Forums for assistance. We'll be delivering additional findings on this new driver at Phoronix as they develop.