Dexconf retrieves values from debconf's database and uses them to build an XF86Config or XF86Config-4 (depending on the default X server selected) file.
The information that dexconf uses is typically entered via a debconf frontend (or possibly in part by hardware autodetection tools). Note that dexconf itself does not set any values in the debconf database; it only retrieves them. If configuration parameters of the debconf database need to be changed, dpkg-reconfigure(8) should be used to do so.
It is also important to note that dexconf, and the corresponding debconf questions whose answers it retrieves, are not intended to replace a full-featured X server configuration tool; that is the province of xf86cfg(1), currently under development by the XFree86 Project, Inc. In the meantime, however, users inexperienced with the syntax of the XF86Config (or XF86Config-4) file may use dexconf to generate the X server configuration file with a minimal amount of detailed knowledge of their hardware characteristics.
More experienced users should feel free to use Dexconf-generated configuration files as a starting point for their customizations, since individual preferences vary greatly.
Dexconf decides which file (XF86Config or XF86Config-4) to generate based upon the name of the default X server (a debconf question).
Dexconf writes only to the area between
in the configuration file. Anything outside this region is preserved. If either or both of the above marker lines is missing, dexconf will exit with an error.
The above feature is useful especially in conjuction with the version 4 XFree86 X server, so that additional input devices, display devices, and monitors can be configured, and multiple screens and layouts defined. For instance, the first !ServerLayout? section encountered in the configuration file is the one XFree86 4 uses as its default, so a typical customization is to write a !ServerLayout? section at the top of the file, before the beginning of the debconf area. See XF86Config-4(5) and the Debian X FAQ --
Configuration file for the XFree86 4.x X server.