Reconfigure the X Server with Debconf
Until Woody, reconfiguring the X Server using debconf was a matter of knowing which package is the X Server currently used, and reconfiguring it like so:# dpkg-reconfigure xserver-xfree86
Of course, any changes made by hand were lost then.
Starting from Sarge, Debconf holds a checksum of the /etc/X11/XF86Config-4 file and only modifies it if the checksum still applies (ie if you didn't bring changes in it by hand). If you modified it but want to force it to write the changes made with Debconf, you have to regenerate the checksum by hand. Be careful, this will of course lose all your hand-made settings. To do so on Sarge:# md5sum /etc/X11/XF86Config-4 > /var/lib/xfree86/XF86Config-4.md5sumFor Etch and superior, which use Xorg instead of XFree86:
# md5sum /etc/X11/xorg.conf > /var/lib/x11/xorg.conf.md5sum
Then, you can use the upper command back.