5. The X Server

The X server (XF68_FBDev) is the most notable application program for the frame buffer device. Starting with XFree86 release 3.2, the X server is part of XFree86 and has 2 modes:

• If the Display subsection for the fbdev driver in the /etc/XF86Config file contains a

          Modes "default"
  	
  

  line, the X server will use the scheme discussed above, i.e. it will start up in the resolution determined by /dev/fb0 (or $FRAMEBUFFER, if set). You still have to specify the color depth (using the Depth keyword) and virtual resolution (using the Virtual keyword) though. This is the default for the configuration file supplied with XFree86. It's the most simple configuration, but it has some limitations.
• Therefore it's also possible to specify resolutions in the /etc/XF86Config file. This allows for on-the-fly resolution switching while retaining the same virtual desktop size. The frame buffer device that's used is still /dev/fb0 (or $FRAMEBUFFER), but the available resolutions are defined by /etc/XF86Config now. The disadvantage is that you have to specify the timings in a different format (but fbset -x may help).

To tune a video mode, you can use fbset or xvidtune. Note that xvidtune doesn't work 100% with XF68_FBDev: the reported clock values are always incorrect.