Using the Correct Video Driver

Under XFree86 4.x, you set the video driver in the Device section, which typically looks like this:

Section "Device" Identifier "devicel" VendorName "ATI" BoardName "ATI Mach64 Utah" Driver "ati" EndSection

The Identifier line names the device so that it may be referred to by name in the Screen section. The VendorName and BoardName options are names for your own use; you can set them to whatever values you like. The Driver line is the single most important line in the Device section because it sets the driver that XFree86 uses for the video card. To determine which driver to use for your card, consult the XFree86 documentation, and particularly the device page at

http://www.xfree86.org/current/Status.html. This page includes links for many different video chipset manufacturers. For instance, if you have a Trident chipset, click the Trident Microsystems link. The resulting page provides information in three categories:

3.3.6 This section tells you how to use XFree86 3.3.6 (the last of the 3.x series) with the video card. Information includes the name of the X server executable to run and a list of cards or chipsets that work with that server.

4.3.0 This section's name is likely to change to reflect the current software version by the time you read this. It summarizes the driver name you provide on the Driver line and lists the cards or chipsets supported by the driver.

Summary This section provides a summary of which cards or chipsets are supported by XFree86 3.3.6 and 4.x. Be sure to check this section; you may learn that your card has substantially better support in one version of XFree86 or another.

In most cases, you can get XFree86 4.x to work well with your card, but you must normally be able to identify the chipset the card uses, or at least the chipset's manufacturer. (Many drivers can identify the specific chipset model; for instance, the ati driver supports and can correctly identify most ATI chipsets, so you may not need to know your exact chipset model number.) Chapter 1, "Optimizing System Architecture Usage," provides pointers on identifying chipsets.

Because XFree86 4.x uses a modular driver system, some video card manufacturers have begun to provide XFree86 4.x drivers for their video cards. You may want to check with the manufacturer to see if this is true of your video card, particularly if the card is a new model. XFree86's developers usually can't produce accelerated drivers for a video card until several months after it's released, so manufacturer-provided drivers might produce better results initially.

Two drivers deserve special attention: fbdev and vga. These drivers enable Linux to work with a display even if a hardware-specific driver isn't available. The fbdev driver works with a frame buffer device, which is an abstraction of the video hardware provided by the Linux kernel. The fbdev driver isn't often used on IA-32 systems, but it's fairly common on other platforms. The vga driver works by using lowest-common-denominator hardware standards, much as full-screen games do. You might try one or both of these drivers if you can't get your video card to work in any other way, but these drivers are limited. Most importantly, they're likely to be slower than a regular driver. They may also support only a limited range of resolutions. The fbdev driver requires kernel support for your video card.

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