Comment 53 for bug 296167

I hadn't expected that others would be so interested in how to downgrade or I wouldn't have taken some notes. Here is what I did as best I can remember:

Logged in to a text console as root and shut down X with '/etc/init.d/gdm stop'.

Add the following lines to my /etc/apt/sources.list :

deb http://us.archive.ubuntu.com/ubuntu hardy main
deb http://us.archive.ubuntu.com/ubuntu hardy-updates main
deb http://us.archive.ubuntu.com/ubuntu hardy-security main

At this point I tried to purge all the xorg packages I could with:
cd /var/lib/dpkg/info/
dpkg --purge `ls *xorg*.list | sed s/.list// `

Obviously it won't remove all the packages because of the dependencies of other packages. I am starting to think that step wasn't necessary as I think the next step would have resulted in those packages being removed anyway. After a little trial and error I found that I needed to downgrade the following packages on my system. ( note I have a matrox card, so please substitute the correct video driver for your hardware in place of the mga driver ):

apt-get --reinstall install x11-common/hardy xorg/hardy xserver-xorg/hardy xserver-xorg-core/hardy xserver-xorg-input-kbd/hardy xserver-xorg-input-mouse/hardy xserver-xorg-video-mga/hardy

After that I restarted the X with "/etc/init.d/gdm start" and logged in and everything worked for me. The final step was to go into synaptic and lock those 7 packages so the upgrade manager would stop bothering me.