DVI output with ATI RV280 series graphics cards is broken in xorg. This is caused by a bug in the xorg ati/radeon driver. A solution to the problem is provided by this instruction (requires recompiling the driver).
This HOWTO was written for Edgy. The problem still exists in Feisty, however the name of the package has changed. Please change every instance of "xserver-xorg-driver-ati" with "xserver-xorg-video-ati" for this to work on Feisty.
To recompile the driver we need some packages installed on our system.
$ sudo apt-get install build-essential fakeroot $ sudo apt-get build-dep xserver-xorg-driver-ati
In a new empty directory (our build directory) run:
$ apt-get source xserver-xorg-driver-ati
This downloads three files and unpacks the sources into the directory xserver-xorg-driver-ati-version. In this directory is the file src/radeon_bios.c, that we need to edit. Towards the end of this file is a comment saying:
/* revision 4 has some problem as it appears in RV280, comment it off for now, use default instead */
And after this comment follows a code block that has been commented out. We need to re-enable this code by removing the commenting-out. In my case deleting lines 574 and 561 did the job.
Now we can build the driver by running:
$ dpkg-buildpackage -rfakeroot -uc -b
from within the directory that was created for the package after downloading.
To install it run:
sudo dpkg -i xserver-xorg-driver-ati_220.127.116.11-0ubuntu7_i386.deb
from within our build directory.