I need to configure a couple of options for the nvidia driver, e.g. Coolbits. For this I have /etc/X11/xorg.conf which contains purely my manual configuration. I have found that this file is being renamed xorg.conf.<MMDDYYYY> at irregular intervals, thereby disabling these manual settings.
/var/lib/dpkg/info/nvidia-prime.postrm is very likely what's causing this:
case "$1" in
purge|remove|upgrade|failed-upgrade|abort-install|abort-upgrade|disappear)
# Remove the xorg.conf
if [ -f $xorg_conf ]; then
mv $xorg_conf $xorg_conf.$now
fi
Iiuc this is run on every upgrade of the nvidia-prime package. I don't know the reasons for doing this, but given that /etc/X11/xorg.conf is still intended (only) for manual configuration, it should not summarily be moved away. If there's a risk for conflicting old configs then they should be detected more accurately and handled through the normal tools that updates/replaces /etc files containing local changes.
This is happening to me on a regular basis as well, and is annoying. The nvidia driver doesn't recognize the DPI properly and so I am left with VERY LARGE TEXT, so it's easy to recognize when this happens. Every time I have to rename the file back to xorg.conf. I don't understand why packages are touching this file at all. It should be left to the user to configure their X. Especially since Ubuntu doesn't create this file by default, if the user put it there, leave it there.