[GLLUG] Debian Video/Screen Problem (i'm sure it'll be a simple fix)

[C. Ulrich]

On Sat, 2004-01-03 at 11:00, Mark Tarquini wrote:
> I have posted the log files and the XF86Config file(s) at the following location:
> 
> http://www.iametarq.com/debian/
> 
> I'll also add the following note to my confusion...The log file says that it is
> using the file /etc/X11/XF86Config-4 for my video settings etc...but there is
> also a "XF86Config" in /usr/X11R6/lib/X11/ and *that* XF86Config file actually
> has the correct labelling and names of all my video devices (as you'll see in
> the files).  I'm rather confused on what linux is doing here.
> 
> Thanks for all the help!

Hello! I didn't see anyone respond to this yet, so I'll take a crack at
it.

According to the XF86Config(5) man page, the XFree86 will look for
configuration files in a particular order. To save space, I've cut out
the ones that don't normally apply to most setups.

/etc/X11/XF86Config-4
/etc/X11/XF86Config
/etc/XF86Config
/usr/X11R6/etc/X11/XF86Config-4
/usr/X11R6/etc/X11/XF86Config
/usr/X11R6/lib/X11/XF86Config-4
/usr/X11R6/lib/X11/XF86Config

In practice, you usually only need to remember that XFree86 will look
for a config file first in /etc/X11, then in /etc, then in the
/usr/X11R6 tree. XF86Config-4 will take precedence over a XF86Config
if the two reside in the same directory.

Just to make matters confusing, the search order is different if XFree86
is being run by root. You might find that X works just fine when started
by "startx" on the command line but fails horribly when you try to start
a graphical login manager. Your particular setup shouldn't be affected
(at the moment) since /usr/X11R6/lib/X11/XF86Config is at the very
bottom of both lists.

The reason that it looks for an XF86Config-4 in addition to the standard
XF86Config is because the file format changed for XFree86 4.x and the
developers wanted to be able to test XFree86 4.x without affecting their
working 3.x setups. IMHO, this was completely the wrong way to go about
it, since that caused distributions to start shipping with XF86Config-4
*and* XF86Config, resulting in no end of difficulty for newer users and
those trying to help them. :) It would be understandable if XFree86
treats XF86Config only as a 3.x config file and XF86Config-4 only as a
4.x config file, but this is not the case.

In the Monitor section, you have the following:

HorizSync	30-70
VertRefresh	50-160

While these settings most likely won't cause any problems, you should
still set them to the correct values for your monitor, which are:

HorizSync	30-85
VertRefresh	48-120

Before going any further, note that the following is speculation since I
can't see your log file. In particular, I have no idea which version of
XFree86 you are using, so I'm going to assume that it's 4.3.0.

In the device section of your video card, you have:

Driver		"ati"

This could be wrong. I can't seem to find any documentation for this
driver, but from what I can tell it seems to be for non-Radeon ATI
cards. It would be helpful if you could mention which particular Radeon
card you have. But in any case, try the "radeon" driver and see what
happens. (See radeon(4) for details on the driver.)

Finally, (this is getting to be a long email, isn't it) take note of the
caution at the top of your XF86Config-4 file. I know very little of
Debian, but it says that there's some kind of Debian-specific way of
modifying the config file and that your changes will be lost if you try
to use some configuration tool. If you don't want to bother with all
that now, you could just modify the file right now and keep a backup of
it somewhere so that if Debian does change the file, you can still go
back and see what your modifications were.

Hope this helps! If not, maybe we can get this X business figured out on
Thursday.

Charles Ulrich
-- 
http://bityard.net