5.4 X11 Configuration

Contributed by Christopher Shumway.

5.4.1 Before Starting

Before configuration of X11 the following information about the target system is needed:

Monitor specifications
Video Adapter chipset
Video Adapter memory

The specifications for the monitor are used by X11 to determine the resolution and refresh rate to run at. These specifications can usually be obtained from the documentation that came with the monitor or from the manufacturer's website. There are two ranges of numbers that are needed, the horizontal scan rate and the vertical synchronization rate.

The video adapter's chipset defines what driver module X11 uses to talk to the graphics hardware. With most chipsets, this can be automatically determined, but it is still useful to know in case the automatic detection does not work correctly.

Video memory on the graphic adapter determines the resolution and color depth which the system can run at. This is important to know so the user knows the limitations of the system.

5.4.2 Configuring X11

Configuration of X11 is a multi-step process. The first step is to build an initial configuration file. As the super user, simply run:

# Xorg -configure

In the case of XFree86 type:

# XFree86 -configure

This will generate an X11 configuration skeleton file in the /root directory called xorg.conf.new (whether you su(1) or do a direct login affects the inherited supervisor $HOME directory variable). For XFree86, this configuration file is called XF86Config.new. The X11 program will attempt to probe the graphics hardware on the system and write a configuration file to load the proper drivers for the detected hardware on the target system.

The next step is to test the existing configuration to verify that Xorg can work with the graphics hardware on the target system. To perform this task, type:

# Xorg -config xorg.conf.new

XFree86 users will type:

# XFree86 -xf86config XF86Config.new

If a black and grey grid and an X mouse cursor appear, the configuration was successful. To exit the test, just press Ctrl+Alt+Backspace simultaneously.

Note: If the mouse does not work, you will need to first configure it before proceeding. See Section 2.9.10 in the FreeBSD install chapter.

Next, tune the xorg.conf.new (or XF86Config.new if you are running XFree86) configuration file to taste. Open the file in a text editor such as emacs(1) or ee(1). First, add the frequencies for the target system's monitor. These are usually expressed as a horizontal and vertical synchronization rate. These values are added to the xorg.conf.new file under the "Monitor" section:

Section "Monitor"
        Identifier   "Monitor0"
        VendorName   "Monitor Vendor"
        ModelName    "Monitor Model"
        HorizSync    30-107
        VertRefresh  48-120
EndSection

The HorizSync and VertRefresh keywords may be missing in the configuration file. If they are, they need to be added, with the correct horizontal synchronization rate placed after the HorizSync keyword and the vertical synchronization rate after the VertRefresh keyword. In the example above the target monitor's rates were entered.

X allows DPMS (Energy Star) features to be used with capable monitors. The xset(1) program controls the time-outs and can force standby, suspend, or off modes. If you wish to enable DPMS features for your monitor, you must add the following line to the monitor section:

        Option       "DPMS"

While the xorg.conf.new (or XF86Config.new) configuration file is still open in an editor, select the default resolution and color depth desired. This is defined in the "Screen" section:

Section "Screen"
        Identifier "Screen0"
        Device     "Card0"
        Monitor    "Monitor0"
        DefaultDepth 24
        SubSection "Display"
                Viewport  0 0
                Depth     24
                Modes     "1024x768"
        EndSubSection
EndSection

The DefaultDepth keyword describes the color depth to run at by default. This can be overridden with the -depth command line switch to Xorg(1) (or XFree86(1)). The Modes keyword describes the resolution to run at for the given color depth. Note that only VESA standard modes are supported as defined by the target system's graphics hardware. In the example above, the default color depth is twenty-four bits per pixel. At this color depth, the accepted resolution is 1024 by 768 pixels.

Finally, write the configuration file and test it using the test mode given above.

Note: One of the tools available to assist you during troubleshooting process are the X11 log files, which contain information on each device that the X11 server attaches to. Xorg log file names are in the format of /var/log/Xorg.0.log (XFree86 log file names follow the format of XFree86.0.log). The exact name of the log can vary from Xorg.0.log to Xorg.8.log and so forth.

If all is well, the configuration file needs to be installed in a common location where Xorg(1) (or XFree86(1)) can find it. This is typically /etc/X11/xorg.conf or /usr/X11R6/etc/X11/xorg.conf (for XFree86 it is called /etc/X11/XF86Config or /usr/X11R6/etc/X11/XF86Config).

# cp xorg.conf.new /etc/X11/xorg.conf

For XFree86:

# cp XF86Config.new /etc/X11/XF86Config

The X11 configuration process is now complete. In order to start XFree86 4.X with startx(1), install the x11/wrapper port. Xorg already includes the wrapper code and does not require the installation of the wrapper port. The X11 server may also be started with the use of xdm(1).

Note: There is also a graphical configuration tool, xorgcfg(1) ( xf86cfg(1) for XFree86), that comes with the X11 distribution. It allows you to interactively define your configuration by choosing the appropriate drivers and settings. This program can be invoked from the console, by typing the command xorgcfg -textmode. For more details, refer to the xorgcfg(1) and xf86cfg(1) manual pages.

Alternatively, there is also a tool called xorgconfig(1) ( xf86config(1) for XFree86), this program is a console utility that is less user friendly, but it may work in situations where the other tools do not.

5.4.3 Advanced Configuration Topics

5.4.3.1 Configuration with Intel® i810 Graphics Chipsets

Configuration with Intel® i810 integrated chipsets requires the agpgart AGP programming interface for X11 to drive the card. The agp(4) driver is in the GENERIC kernel since releases 4.8-RELEASE and 5.0-RELEASE. On prior releases, you will have to add the following line:

device agp

in your kernel configuration file and rebuild a new kernel. Instead, you may want to load the agp.ko kernel module automatically with the loader(8) at boot time. For that, simply add this line to /boot/loader.conf:

agp_load="YES"

Next, if you are running FreeBSD 4.X or earlier, a device node needs to be created for the programming interface. To create the AGP device node, run MAKEDEV(8) in the /dev directory:

# cd /dev
# sh MAKEDEV agpgart

Note: FreeBSD 5.X or later will use devfs(5) to allocate device nodes transparently, therefore the MAKEDEV(8) step is not required.

This will allow configuration of the hardware as any other graphics board. Note on systems without the agp(4) driver compiled in the kernel, trying to load the module with kldload(8) will not work. This driver has to be in the kernel at boot time through being compiled in or using /boot/loader.conf.

If you are using XFree86 4.1.0 (or later) and messages about unresolved symbols like fbPictureInit appear, try adding the following line after Driver "i810" in the X11 configuration file:

Option "NoDDC"