Linux Unleashed, Third Edition:Installing and Configuring XFree86

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Configuring XFree86

Before you can run XFree86, some configuration information should be specified. This is the part that tends to frustrate newcomers to XFree86, as it can be a convoluted process to get your configuration files exactly right and allow XFree86 to execute properly. Hopefully, a few simple step-by-step instructions will streamline the process.

There is a utility called either ConfigFX86 or fx86config provided with many distributions of Linux and XFree86 that simplify the entire XFree86 installation process, but only if you have one of the supported graphics cards. A list of cards supported by ConfigFX86 and fx86config is usually included in the Hardware HOWTO file provided with the Linux distribution software. If you can’t find the HOWTO file, it can be obtained from most FTP and BBS locations. Make sure the version of the file corresponds to the Linux version you are running. More details about ConfigFX86 and fx86config are provided in the later section “Using ConfigFX86 and fx86config.” (You can, in some cases, provide enough information for ConfigFX86 and fx86config to use your unlisted video card for the installation. This is discussed in the following section.)

If you don’t have the Hardware HOWTO file or your video card is not listed and you don’t want to use a generic driver, then you must manually configure XFree86. Even if you use the ConfigXF86 or fx86config script to install XFree86, you may still have to make manual modifications to tweak your installation.

Most of the configuration details for XFree86 version 2.X are contained in a file called Xconfig, whereas XFree86 version 3.X uses a file called XF86Config or Xconfig, depending on the version. The bare-bones instructions for setting up an Xconfig or XF86Config file are spread out over several text files included with the XFree86 distribution set. In most cases, you should check the README, VideoModes.doc, README.Config, and README.Linux files. That’s not all: You also have to read the man pages for Xconfig, XF86Config XFree86, and XFree86kbd. Finally, you should check the man pages for the server version you are running, if one is provided. (It’s a good idea to print out the man pages for easier reference.)

There are a few items of information you need to properly complete the Xconfig or FX86Config file. Before you start configuring XFree86, take a moment to note the following details:

• The XFree86 server to be used.

• The type of mouse on your system and the port it is connected to.

• Your video card’s brand name and chipset. If you’re not sure of the chipset, either consult your documentation or use a utility program such as SuperProbe (Linux) or MSD (DOS).

• Your video monitor brand name and model number, as well as the size of the monitor. It also helps to know the maximum horizontal and vertical scan frequencies, usually available from the monitor’s documentation.

• The type of keyboard you will be using if not the U.S. generic type. Most users have the U.S. type, although some countries have customized keyboards that require different key mappings.

If you don’t know some of the information and don’t have an easy way (such as a utility program) to find out, you should check the documentation that comes with XFree86. Many distributions contain a directory such as /usr/X11/lib/X11/doc (usually linked to /usr/X386/lib/X11/doc or /usr/X11R6/lib/X11/doc) that contains a number of files describing many cards and monitors supported by XFree86 and the essential configuration information (such as monitor scan rates, which are always difficult to determine because you invariably can’t remember where you placed the manual).

When you’ve noted all this configuration information, you are ready to start configuring XFree86. This all begins with the Xconfig or XF86Config file.

Where to Put Xconfig or XF86Config

The Xconfig or XF86Config file can be located in several places on the Linux file system. Usually, it resides in the /usr/X386/lib/X11 directory, which is also where a sample Xconfig or XF86Config file is often found. If you have easy access to the /usr/X386/lib/X11 directory, it’s the best place for the Xconfig or XF86Config file. (Formally, the file is referenced in /usr/X11R6/lib/X11 or /etc, but because /usr/X386 is linked to /usr/X11R6, the two directories point to the same place. You may run into the X11R6 directory referenced in documentation, but as long as the link to the X386 directory is in place, you can use either.)

Note:
Unless you are manually installing configuration information, don’t worry about whether you should be using Xconfig or XF86Config. Automated installation scripts will use the proper file. If you are performing a manual configuration, use XConfig for XFree86 version 2.X and XFConfig for XFree86 version 3.X.

If you can’t use /usr/X386/lib/X11 (maybe it’s read-only or on a remote server) or don’t want to because you need a customized version of the Xconfig file, the file can also be placed in the /etc directory or in your home directory. If the Xconfig file is in your home directory, it will apply only to your sessions and any configuration information will not be valid for other users. The /etc directory location for the XFree86 Xconfig file means the configuration information is applicable to all users.

You can also put the Xconfig file in the directory /usr/X386/lib/X11 specific to a particular host machine. To do this, the Xconfig filename is appended with the name of the host machine. For example, the file Xconfig.merlin will apply the configuration information only to users logging in from the machine “merlin.”

The Linux convention for the Xconfig file is to place it in the /etc directory. Because this is not the usual location for XFree86 installations, a link must be created to the /etc/Xconfig file to /usr/X386/lib/X11 or your home directory. This allows XFree86 to find the Xconfig file properly.

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