Configuring XFree86 to use your mouse, keyboard, monitor, and video
card correctly used to be something of a black art, requiring
extensive hand-hacking of a complex configuration file. No more; the
3.2/3.3 released made the process nearly trivial. All you do is
fire up the program
This program depends on the fact that all new PC hardware these days ships with EGA/VGA capable monitors. It invokes the SVGA16 server and uses it to bring up X in a lowest-common-denominator 640x480 mode. Then it runs an interactive program that walks you through a series of five configuration panels -- mouse, keyboard, (video) card, monitor, and `other' (miscellaneous server options). The whole process is quite painless.
One minor point to keep in mind is that, if you're like most people using current PC, your keyboard is actually what XF86Setup calls `Generic 102-key PC (intl)' rather than the default `Generic 101-key PC'. If you pick the default (101) the key cluster on the extreme right of your keyboard (numeric keypad and friends) may stop working.
If you're not sure of your monitor type, you can try the listed ones in succession. Work your way from top down (upper choices involve lower dot-clock speeds and are less demanding on the hardware). Back off if you get hash or a seriously distorted picture. Minor distortions (picture slightly too large, slightly too small, or slightly off-center) are no problem; you'll get a chance to correct those immediately by fine-tuning the mode.
And, when the program brings up
xvidtune to allow you to tweak
your video mode, don't let the initial warning box make you nervous. Modern
multisync monitors (unlike their fixed-frequency predecessors) are not
easy to damage this way.
Occasionally, something will not be quite right when you initially fire up the
X server. This is almost always caused by a problem in your configuration
file. Usually, the monitor timing values are off, or the video card
dot clocks set incorrectly. Minor problems can be fixed with
a really garbled screen usually means you need to go back into
XF86Setup and choose a less capable monitor type.
If your display seems to roll, or the edges are fuzzy, this is a clear
indication that the monitor timing values or dot clocks are
wrong. Also be sure that you are correctly specifying your video card
chipset, as well as other options for the
Device section of
XF86Config. Be absolutely certain that you are using the
right X server and that
/usr/X11R6/bin/X is a symbolic link
to this server.
If all else fails, try to start X ``bare''; that is, use a command such as:
You can then kill the X server (using the
X > /tmp/x.out 2>&1
ctrl-alt-backspacekey combination) and examine the contents of
/tmp/x.out. The X server will report any warnings or errors---for example, if your video card doesn't have a dot clock corresponding to a mode supported by your monitor.
Remember that you can use
ctrl-alt-numeric + and
ctrl-alt-numeric - to switch between the video modes
listed on the
Modes line of the
Screen section of
XF86Config. If the highest resolution mode doesn't look right,
try switching to lower resolutions. This will let you know, at least,
that those parts of your X configuration are working correctly.
Also, check the vertical and horizontal size/hold knobs on your monitor. In many cases it is necessary to adjust these when starting up X. For example, if the display seems to be shifted slightly to one side, you can usually correct this using the monitor controls.
The USENET newsgroup
comp.windows.x.i386unix is devoted to
discussions about XFree86, as is
It might be a good idea to watch that newsgroup
for postings relating to your video configuration---you might run across
someone with the same problems as your own.
You will need to hand-hack your X configuration to get optimal performance if your monitor can support 1600x1200 -- the highest canned resolution XF86Setup supports is 1280x1024.
If you want to hand-hack your video configuration for this or any other reason, go see the LDP's XFree86 Video Timings HOWTO, http://sunsite.unc.edu/LDP/HOWTO/video-modes.html. (This is the up-to-date HTML version of XFree86's `Videomodes.doc' file.)
By default, X uses 8-bit color depth giving 256 colors. To circumvent this restriction, many applications allocate their own colormaps, resulting in sudden color jumps when the cursor moves between two windows each having a color map of its own. The Arena WWW browser does it this way.
If you want to use advanced graphic applications 256 colors may be not sufficient. You can use 16bit color depth with 65K different colors simply by starting X with
startx -- -bpp 16
exec X :0 -bpp 16
into your .xserverrc file. But beware, not all applications will work with 16bit colors.
More colors makes your video card transfer more data during the same time. If your video card cannot cope, then either the resolution has or the refresh rate has to be reduced. By default, XFree reduces the resolution. If you want to keep the resolution and reduce the refresh rate, you must insert a new appropriate Modeline into your XF86Config file which defines that resolution with a lower refresh rate. For instance replace the old value
Modeline "1024x768" 75 1024 1048 1184 1328 768 771 777 806 -hsync -vsync
The magic numbers 75 and 65 are the respective clock rates which you find reported by X in your .X.err file. Consult the monitors file in the XF86 documentation for Modelines suitable to the maximum clock rate your video card can deliver under 16bit color depth.
Modeline "1024x768" 65 1024 1032 1176 1344 768 771 777 806 -hsync -vsync.