If you’re like me and you updated your Linux desktop to find Xorg (because of nVidia) no longer played with XDM, KDM, or GDM then you’ve hit the hilarious ignoreABI bug.
For some people, editing their /etc/X11/xorg.conf works:
Section "ServerFlags" Option "IgnoreABI" "True" EndSection
Not me. No matter what flags I tried to pass in via xorg.conf, it wouldn’t go. Probably because sometimes the GUI is looking for the configuration, othertimes it’s not. According to /var/log/kdm.log it was, but it cowardly refused to honor that directive.
The fact that the ubuntu guys call it a “good driver” just means the typical ubuntu user has no idea what a good driver looks like.
Finally someone with half a brain ran into this on Xorg 1.5 and their new nVidia card. You can read their fix here, it’s basically what you would expect. Shim out /usr/bin/Xorg with a script, have the script call the other Xorg.0 executable and pass all the arguments with -ignoreABI. Incidentally something really strange is happening here because editing /etc/X11/xinit/xserverrc to add -ignoreABI to the args line doesn’t get passed to Xorg.