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Laptops and X

If your hardware includes a laptop computer, you may be able to run X on it. Many others have taken the time to configure X on a wide range of laptops. If you have a ThinkPad laptop, for example, there’s a wealth of information specific to Linux on the World Wide Web at URL http://peipa.essex.ac.uk/tp-linux/tp-linux.html.


ON THE CD-ROMS:  This Web page is available on the CD-ROMs in the /docs directory.

This Web page also contains a number of X configuration files for various ThinkPad models.

You are likely to have problems with the ThinkPad 700, 720, and any other MCA-architecture machines, as Linux does not yet support MCA. The Linux Laptop Home Page (http://www.cs.utexas.edu/users/kharker/linux-laptop/) has a lot of information about setting up X with laptops.


WARNING:  If you have a model 760, you may have problems with the latest editions of XFree86. See the Linux Notebook Web page at URL http://www.castle.net/X-notebook/index_linux.html. Because versions of X change rapidly, this problem may already be fixed.

Some of the key bits of information you want to discover about your system are listed in Table 3.6.

Table 3.6 Information You Need to Know about Your System
Aspect What You Need to Know

Card Vendor and model, of course
Card Chipset, such as S3
Card Amount of video RAM, such as 1 or 2MB
Card RAMDAC, if one is used, such as ATT20C490
Monitor Bandwidth in megahertz (MHz), such as 25.2
Monitor Horizontal Sync range, such as 31.5–64.3 kilohertz (kHz)
Monitor Vertical refresh range, such as 55–120 Hertz (Hz)
Mouse Serial or parallel? If serial, which serial port it’s connected to
Mouse Vendor and model, such as Logitech Firstmouse

Note that some of the more obscure details, such as the RAMDAC, may be described for you in the XFree86 documentation. XFree86 comes with a description of a number of graphics cards and monitors. If you’re lucky, you can pull some of these values directly from the XFree86 documentation into your XF86Config file, the master file that describes your hardware to X.

Normally located in /usr/X11R6/lib/X11, the XF86Config file is an ASCII text file, formatted in a special way that the XFree86 X server understands. By default, XFree86 searches for this file in a number of directories, in the following order:

/etc/XF86Config
<Xroot>/lib/X11/XF86Config.hostname
<Xroot>/lib/X11/XF86Config

The <Xroot> is shorthand for the top-level X directory. In Slackware Linux, this is /usr/X11R6. Previous to release 6 of X11 (hence the X11R6), XFree86’s top directory was /usr/X386.

You can create the XF86Config file with a text editor such as vi or emacs. In most cases, though, you’ll want to copy an example file to avoid entering the whole thing. Under Slackware, this example file is named XF86Config.eg. While this example is not ready to go, you can get a lot of useful information out of it. (See the section on Super VGA.)

In the XF86Config file, each section follows the same basic pattern:


  Section "SectionName"

    data entry...

    ...

  EndSection

The # acts as a comment character, which is very useful in documenting the odd syntax in the XF86Config file.

In the next sections of this chapter, we’ll cover these six sections in depth and show how you can automate part of the process by using a program called xf86config.


WARNING:  Never use someone else’s XF86Config file. And don’t use the examples we provide verbatim. Always configure X for your hardware. Wrong data in the file may cause X to damage your hardware.

Automating the Configuration Process

For a number of years, various programs have attempted to automate the difficult creation of XF86Config files. So far, though, all have failed miserably for us—that is, until the most recent versions and a program called xf86config. For the first time, xf86config seems to create a workable XF86Config file, and we don’t even have any odd hardware.

Before running xf86config, read over each of the following sections which describe the various parts of the XF86Config file that the xf86config program will be filling in. By having a greater understanding of the XF86Config file, your success rate with the xf86config program will be much greater.

Because of this, we’ll discuss each of the six sections and then cover using xf86config.


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