Often, something will not be
quite right when you initially fire up the X server. This is almost
always caused by a problem in your XF86Config
file. Usually, the monitor timing values are off or the video card
dot clocks are set incorrectly. 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 you are correctly
specifying your video card chipset, as well as other options for the
Device
section of XF86Config
.
As of XFree86 Version 4, there is only one server binary, which loads
the module needed for the graphics card in question. The module that
loads depends on your Device
settings.
If all else fails, try to start X “bare”; that is, use a command, such as:
X > /tmp/x.out 2>&1
You can then kill the X server (using the Ctrl-Alt-Backspace key
combination) and examine the contents of
/tmp/x.out
. The X server reports any warnings or
errors — for example, if your video card doesn’t
have a dot clock corresponding to a mode supported by your monitor.
This output can be very helpful in diagnosing all kinds of problems.
Examine it closely if your X server does not start up at all, does
not provide the resolutions you wanted, or shows a flaky, snowy, or
otherwise insufficient picture. Even if everything works to your
satisfaction, you might want to check this file for interesting
information that the X server has found out about your hardware. The
lines starting with (**)
contain data that you
provided yourself in the configuration file, while lines starting
with (- -)
contain data that the X server has
found out itself.
Remember that you can use Ctrl-Alt with the plus or minus keys on the
numeric keypad 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 lets you know, at least, that the configurations
for those lower resolutions in 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. 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. If this fails, please contact your Linux distributor; their support staff should be able to help you as well.