======
README
======

The most updated documentation is available at our wiki:
http://wiki.c3sl.ufpr.br/multiseat

It is also available in other languages there.

This document is just a copy of a 2 pages on the wiki. It follows MediaWiki
syntax. For the most updated version, see these pages:

- http://wiki.c3sl.ufpr.br/multiseat/index.php/Mdm
- http://wiki.c3sl.ufpr.br/multiseat/index.php/Compiling_mdm


========================
Multisat Display Manager
========================


'''mdm''' stands for "multiseat display manager". Despite its name, mdm is actually a wrapper on the real display manager. It is used to configure multiseat environments, allowing users to change a normal machine into a multiseat machine by just installing a package.

==The problem==

There are many ways to configure multiseat environments. Some people use nested X servers, while others use multiple instances of the X server or maybe VNC or directfb or anything else. Also, combined with these solutions people might want to use GDM, KDM, XDM, remote X without display managers or many others. The goal of the mdm package is to be generic enough to be able to be used in any solution.

==The solution==

mdm consists of two disctinct parts: the ''core'', simply called mdm, which is the solution-independent code, and the ''multiseat mode'', which is the solution-dependent code. The ''core'' is installed by the mdm package and the other multiseat modes are installed by the other packages (like mdm-xephyr-gdm, which combines Xephyr and GDM). There are also some default modes inside the mdm package, like the xephyr-xdmcp, which just starts X servers connected to remote xdmcp servers. Modes that have extra dependencies are provided by other packages.

===mdm===

The ''core'' package is responsible for detecting input devices, video cards, creating xorg.conf, associating seats with devices and then calling the modes

===[[multiseat modes]]===

The modes are actually bash scripts that define some specific functions that are called to start the displays used by the seats. They are usually located in /usr/share/mdm/modes. To change between modes, it is necessary to edit the MULTISEAT_MODE variable inside the [[mdm.conf|mdm configuration file]].

==Using mdm==

There are 3 ways to use mdm. You can:
* [[Installing mdm|install]] the mdm package from our repositories;
* [[Compiling mdm|compile]] and install mdm from git
* or download our [[Live-CD]] and boot it in your machine.

You'll have to install the main mdm package, the package for the multiseat mode you want to use and then edit the [[mdm.conf|mdm configuration file]] to use the right mode and change other preferences.



=========
COMPILING
=========

This page contains instructions on how to compile mdm from git.

==Dependencies==

The first thing you'll need is to download the dependencies. Our dependencies include: [http://git.or.cz/ git], the  essential packages for compiling source code (gcc, make), the cairo library and development files and the fakeroot package

For Debian/Ubuntu users, you can use this command:
 sudo apt-get install git-core build-essential libcairo2-dev libcairo2 fakeroot

==Downloading the files==

To download the repository, use this command:

 git-clone http://git.c3sl.ufpr.br/pub/scm/multiseat/mdm.git

It will create a directory called ''mdm''. Change to it:

 cd mdm

==Compiling==

Our repository consists of 3 main parts:

* The ''mdm'' directory, which generates the package called mdm
* The ''extra-modes'' directory, which includes the non-default [[multiseat modes]]
* The '''dependencies''' directory, which includes a patch for libx11. This patch is needed because without it Xephyr will keep randomly dying. You ''can'' use mdm without it, but as soon as your sessions start dying, you'll want this patch. If you don't use Xephyr, you don't need this patch. The patch fixes [https://bugs.freedesktop.org/show_bug.cgi?id=6820 freedesktop.org's bug #6820]

====Compiling mdm====

Change to the mdm sub-directory

 cd mdm

Compile the source code

 make

Install it to system root (/)

 make install

Or, to install to another directory

 make DESTDIR={target-directory} install

Go back to main directory

 cd ..

This way will allow you to use mdm through XDMCP.

====Compiling the xephyr-gdm mode====

Change to the xephyr-gdm directory:

 cd extra-modes/xephyr-gdm

Generate the package

 make

Install it to system root (/)

 make DESTDIR=/ install

Or, if you want another directory

 make DESTDIR={target-directory} install

Go back to the main directory

 cd ../..

====Patching libx11-6====

Change to your distribution's dependencies directory

 cd dependencies/

Install the pre-requisites for recompiling libx11

 sudo apt-get build-dep libx11-6

Then, use this command to compile and install the package:

 sudo make install

It will download the sources, apply the patches, and put the libx11-6 package in ''hold'' status.


==Configuring the package==

To configure it, edit [[mdm.conf]].

 sudo vim /etc/mdm/mdm.conf

Adjust your monitor mode, frequency, keyboard layout and multiseat mode (use ''xephyr-gdm'' if you want gdm).

==Running==

mdm is configured to automatically start whenever your computer boots. You can either reboot or:

 sudo /etc/init.d/mdm start