If you're using Slackware, or another sane distribution, /etc/X11/xorg.conf.d/ is where you put user-specific X configuration. Making the config immutable would

If you're using Slackware, or another sane distribution, /etc/X11/xorg.conf.d/ is where you put user-specific X configuration. Making the config immutable would prevent overwrite. Making local edits in any part of /usr/ is extremely frowned upon.