[sclug] Debian X win config document

[Philip Hands]

At Mon, 27 Jan 2003 10:51:00 -0000,
Pieter Claassen wrote:
> 
> [1  <text/plain; iso-8859-1 (quoted-printable)>]

> I am sick and tired of hacking X windows to work. Does anybody know
> if there is a X configuration document (FAQ etc) for Woody that I
> can read to understand the config options for X under Debian? 

This might help:

  /usr/share/doc/xfree86-common/FAQ.gz

> I can get it going, but I have the following problems:
> 1. Sometimes, X installs fine on a machine and I get a graphical
>    login that will not allow me to log in as root.

My initial reaction to this question is: Why do you want to log in as
root?  You should log in as yourself, and only use "sudo -s" (or
whatever) to become root when you actually need to.

But to answer your question, you are probably using gdm, with the
default setting (from /etc/gdm/gdm.conf) of:

  [security]
  AllowRoot=false

There's a reason that that's the default though --- many X programs
were never intended to be run as root, so to do so is to point a
loaded gun at your foot.

> 2. Other times I can startx but with a reboot no luck I get a
>    failure with something like "gdm is not your default window
>    manager???".

That's probably:

  Not starting GNOME Display Manager (gdm); it is not the default display manager.

in which case that's because you have something other than
"/usr/bin/gdm" in the file:  /etc/X11/default-display-manager

This is normally setup automatically, based on which display managers
you have installed.  If you want to use gdm, your best bet is probably
to get rid of kdm and xdm, if installed, which should result in
/etc/X11/default-display-manager containing gdm by the end of it.

That is a difference that you'll find with Debian.  You are assumed to
have had a reason for installing packages, so if you install just the
one display manager, it will be the default, if you install several,
you should be prompted at some point for which one you want as
default.  If you then change your mind, there is probably some clever
dpkg-reconfigure incantation to tell the system, but I've never felt
the need to have several display managers at once, so I don't know
what it is.

> 3. Debian seems to have S99X files under rc3.d. I thought Linux only
>    started X under runlevel 5? What should my defaul runlevel be
>    under Debian with X?

Debian doesn't use runlevels to decide if X is supposed to be running.
Runlevel 2 is generally what you want to be running in.  If you want
X, then you install X, and you when you install your display manager,
you say you want it to run (if it asks you).  If you later decide you
don't want X running at boot time, just remove the display manager, and
it won't run any more.

Same goes for things like telnetd --- if you don't want it running,
don't waste time finding out how to stop it from starting, just remove
the package.

> 4. There is a plethora of X documentation (out there) referencing
>    config files that just don't seem to not be on my box.

Most of that documentation is probably assuming you're on a RedHat
box.  Debian tends to have it's configuration files split up into
smaller, possibly more logical, sub-configuration files.  And a few of
the standard commands have wrappers which try to ensure that things
are sane before invoking the real command.

>    Where do I specify the window manager, the desktop manager etc?

Some of that can be selected from the gdm session menu, or you can set
up up in your ~/.xsession, or you used to be able to set up a system
default in /etc/X11/window-managers, but I get the feeling that we're
now using the alternatives system, and that the default is determined
by where /usr/bin/x-window-manager is pointing (check out the
update-alternatives(8) man page for more on alternatives).

>    What is the difference between kdm, gdm etc?

Looks mostly.

>    Can I start the KDE on gdm (I get a error in my syslog that says
>    during boot, Xprt_64: Fatal server error: No screens found? But I
>    can startx.

You can run any X window/session manager, from any of the display
managers, but you might as well use kdm if you are planning to use kde
as your desktop environment, because then the look&feel will be more
consistent. (at least, that's the impression I get --- I use evilwm,
so cute look&feel is not something I aim for).

Cheers, Phil.
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