5.4. Xorg Configuration

Warren Block

5.4.1. Quick Start

Xorg supports most common video cards, keyboards, and pointing devices. These devices are automatically detected and do not require any manual configuration.

  1. If Xorg has been used on this computer before, move or remove any existing configuration files:

    # mv /etc/X11/xorg.conf ~/xorg.conf.etc
    # mv /usr/local/etc/X11/xorg.conf ~/xorg.conf.localetc
  2. Add the user who will run Xorg to the video or wheel group to enable 3D acceleration when available. To add user jru to whichever group is available:

    # pw groupmod video -m jru || pw groupmod wheel -m jru
  3. The TWM window manager is included by default. It is started when Xorg starts:

    % startx
  4. On some older versions of FreeBSD, the system console must be set to vt(4) before switching back to the text console will work properly. See Section 5.4.3, “Kernel Mode Setting (KMS)”.

5.4.2. User Group for Accelerated Video

Access to /dev/dri is needed to allow 3D acceleration on video cards. It is usually simplest to add the user who will be running X to either the video or wheel group. Here, pw(8) is used to add user slurms to the video group, or to the wheel group if there is no video group:

# pw groupmod video -m slurms || pw groupmod wheel -m slurms

5.4.3. Kernel Mode Setting (KMS)

When the computer switches from displaying the console to a higher screen resolution for X, it must set the video output mode. Recent versions of Xorg use a system inside the kernel to do these mode changes more efficiently. Older versions of FreeBSD use sc(4), which is not aware of the KMS system. The end result is that after closing X, the system console is blank, even though it is still working. The newer vt(4) console avoids this problem.

Add this line to /boot/loader.conf to enable vt(4):


5.4.4. Configuration Files Directory

Xorg looks in several directories for configuration files. /usr/local/etc/X11/ is the recommended directory for these files on FreeBSD. Using this directory helps keep application files separate from operating system files.

Storing configuration files in the legacy /etc/X11/ still works. However, this mixes application files with the base FreeBSD files and is not recommended. Single or Multiple Files

It is easier to use multiple files that each configure a specific setting than the traditional single xorg.conf. These files are stored in the xorg.conf.d/ subdirectory of the main configuration file directory. The full path is typically /usr/local/etc/X11/xorg.conf.d/.

Examples of these files are shown later in this section.

The traditional single xorg.conf still works, but is neither as clear nor as flexible as multiple files in the xorg.conf.d/ subdirectory.

5.4.5. Video Cards


3D acceleration is supported on most Intel® graphics, including IronLake, SandyBridge, and IvyBridge.

AMD® Radeon

2D and 3D acceleration is supported on Radeon cards up to and including the HD6000 series.


Several NVIDIA drivers are available in the x11 category of the Ports Collection. Install the driver that matches the video card.

Hybrid Combination Graphics

Some notebook computers add additional graphics processing units to those built into the chipset or processor. Optimus combines Intel® and NVIDIA hardware. Switchable Graphics or Hybrid Graphics are a combination of Intel® and an AMD® Radeon GPU.

Implementations of these hybrid graphics systems vary, and Xorg on FreeBSD is not able to drive all versions of them.

Some computers provide a BIOS option to disable one of the graphics adapters or select a discrete mode which can be used with one of the standard video card drivers. For example, it is sometimes possible to disable the NVIDIA GPU in an Optimus system. The Intel® video can then be used with an Intel® driver.

BIOS settings depend on the model of computer.

Other Video Cards

Drivers for some less-common video cards can be found in the x11-drivers directory of the Ports Collection.

Cards that are not supported by a specific driver might still be usable with the x11-drivers/xf86-video-vesa driver. This driver is installed by x11/xorg. It can also be installed manually as x11-drivers/xf86-video-vesa. Xorg attempts to use this driver when a specific driver is not found for the video card.

x11-drivers/xf86-video-scfb is a similar nonspecialized video driver that works on many UEFI and ARM® computers.

5.4.6. Monitors

Almost all monitors support the Extended Display Identification Data standard (EDID). Xorg uses EDID to communicate with the monitor and detect the supported resolutions and refresh rates. Then it selects the most appropriate combination of settings to use with that monitor.

Other resolutions supported by the monitor can be chosen by setting the desired resolution in configuration files, or after the X server has been started with xrandr(1).

Using xrandr(1)

Run xrandr(1) without any parameters to see a list of video outputs and detected monitor modes:

% xrandr
Screen 0: minimum 320 x 200, current 3000 x 1920, maximum 8192 x 8192
DVI-0 connected primary 1920x1200+1080+0 (normal left inverted right x axis y axis) 495mm x 310mm
   1920x1200     59.95*+
   1600x1200     60.00
   1280x1024     85.02    75.02    60.02
   1280x960      60.00
   1152x864      75.00
   1024x768      85.00    75.08    70.07    60.00
   832x624       74.55
   800x600       75.00    60.32
   640x480       75.00    60.00
   720x400       70.08
DisplayPort-0 disconnected (normal left inverted right x axis y axis)
HDMI-0 disconnected (normal left inverted right x axis y axis)

This shows that the DVI-0 output is being used to display a screen resolution of 1920x1200 pixels at a refresh rate of about 60 Hz. Monitors are not attached to the DisplayPort-0 and HDMI-0 connectors.

Any of the other display modes can be selected with xrandr(1). For example, to switch to 1280x1024 at 60 Hz:

% xrandr --mode 1280x1024 --rate 60

A common task is using the external video output on a notebook computer for a video projector.

Names and types of video connectors vary, so xrandr(1) is run without options to list the outputs:

% xrandr
Screen 0: minimum 320 x 200, current 1366 x 768, maximum 8192 x 8192
LVDS1 connected 1366x768+0+0 (normal left inverted right x axis y axis) 344mm x 193mm
   1366x768      60.04*+
   1024x768      60.00
   800x600       60.32    56.25
   640x480       59.94
VGA1 connected (normal left inverted right x axis y axis)
   1280x1024     60.02 +  75.02
   1280x960      60.00
   1152x864      75.00
   1024x768      75.08    70.07    60.00
   832x624       74.55
   800x600       72.19    75.00    60.32    56.25
   640x480       75.00    72.81    66.67    60.00
   720x400       70.08
HDMI1 disconnected (normal left inverted right x axis y axis)
DP1 disconnected (normal left inverted right x axis y axis)

Four outputs were found: the built-in panel LVDS1, and external VGA1, HDMI1, and DP1 connectors.

The projector has been connected to the VGA1 output. xrandr(1) is now used to set that output to the native resolution of the projector and add the additional space to the right side of the desktop:

% xrandr --output VGA1 --auto --right-of LVDS1

--auto chooses the resolution and refresh rate detected by EDID. If the resolution is not correctly detected, a fixed value can be given with --mode instead of the --auto statement. For example, most projectors can be used with a 1024x768 resolution, which is set with --mode 1024x768.

xrandr(1) is often run from .xinitrc to set the appropriate mode when X starts.

Setting Monitor Resolution in a File

To set a screen resolution of 1024x768 in a configuration file:

Example 5.1. Set Screen Resolution in a File


Section "Screen"
	Identifier "Screen0"
	Device     "Card0"
	SubSection "Display"
	Modes      "1024x768"

The few monitors that do not have EDID can be configured by setting HorizSync and VertRefresh to the range of frequencies supported by the monitor.

Example 5.2. Manually Setting Monitor Frequencies


Section "Monitor"
	Identifier   "Monitor0"
	HorizSync    30-83   # kHz
	VertRefresh  50-76   # Hz

5.4.7. Input Devices Keyboards

Keyboard Layout

The standardized location of keys on a keyboard is called a layout. Layouts and other adjustable parameters are listed in xkeyboard-config(7).

A United States layout is the default. To select an alternate layout, set the XkbLayout and XkbVariant options in an InputClass. This will be applied to all input devices that match the class.

This example selects a French keyboard layout with the oss variant.

Example 5.3. Setting a Keyboard Layout


Section	"InputClass"
	Identifier	"KeyboardDefaults"
	Driver		"keyboard"
	MatchIsKeyboard	"on"
	Option		"XkbLayout" "fr"
	Option		"XkbVariant" "oss"

Example 5.4. Setting Multiple Keyboard Layouts

Set United States, Spanish, and Ukrainian keyboard layouts. Cycle through these layouts by pressing Alt+Shift. x11/xxkb or x11/sbxkb can be used for improved layout switching control and current layout indicators.


Section	"InputClass"
	Identifier	"All Keyboards"
	MatchIsKeyboard	"yes"
	Option		"XkbLayout" "us, es, ua"

Closing Xorg From the Keyboard

A combination of keys is available to close the X system. This option is disabled by default because it conflicts with keyboard commands for some applications. Enabling this option requires changes to both ServerLayout and keyboard InputDevice sections:

Example 5.5. Enabling Keyboard Exit from X


Section "ServerLayout"
	Identifier "EnableZap"
	Option     "DontZap" "Off"


Section	"InputClass"
	Identifier	"KeyboardDefaults"
	Driver		"keyboard"
	MatchIsKeyboard	"on"
	Option		"XkbOptions" "terminate:ctrl_alt_bksp"
EndSection Mice and Pointing Devices

Many mouse parameters can be adjusted with configuration options. See mousedrv(4) for a full list.

Mouse Buttons

The number of buttons on a mouse can be set in the mouse InputDevice section of xorg.conf. To set the number of buttons to 7:

Example 5.6. Setting the Number of Mouse Buttons


Section "InputDevice"
	Identifier  "Mouse0"
	Option      "Buttons" "7"

5.4.8. Manual Configuration

In some cases, Xorg autoconfiguration does not work with particular hardware, or a different configuration is desired. For these cases, a custom configuration file can be created.

A configuration file can be generated by Xorg based on the detected hardware. This file is often a useful starting point for custom configurations.

Generating an xorg.conf:

# Xorg -configure

The configuration file is saved to /root/xorg.conf.new. Make any changes desired, then test that file with:

# Xorg -config /root/xorg.conf.new

After the new configuration has been adjusted and tested, it can be split into smaller files in the normal location, /usr/local/etc/X11/xorg.conf.d/.

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