Xorg/Configuration

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Xorg is the X Window server which allows users to have a graphical environment at their fingertips. This HOWTO explains what Xorg is, how to install it and what the various configuration options are.

What is the X Window Server?

Graphical vs Command-Line

The average user may be frightened at the thought of having to type in commands. Why wouldn't he be able to point and click his way through the freedom provided by Gentoo (and Linux in general)? Well, of course you are able to do this! Linux offers a wide variety of flashy user interfaces and environments which you can install on top of your existing installation.

This is one of the biggest surprises new users come across: a graphical user interface is nothing more than an application which runs on your system. It is not part of the Linux kernel or any other internals of the system. It is a powerful tool that fully enables the graphical abilities of your workstation.

As standards are important, a standard for drawing and moving windows on a screen, interacting with the user through mouse, keyboard and other basic, yet important aspects has been created and named the X Window System, commonly abbreviated as X11 or just X. It is used on Unix, Linux and Unix-like operating systems throughout the world.

The application that provides Linux users with the ability to run graphical user interfaces and that uses the X11 standard is Xorg-X11, a fork of the XFree86 project. XFree86 has decided to use a license that might not be compatible with the GPL license; the use of Xorg is therefore recommended. The official Portage tree does not provide an XFree86 package anymore.

The X.org Project

The X.org project created and maintains a freely redistributable, open-source implementation of the X11 system. It is an open source X11-based desktop infrastructure.

Xorg provides an interface between your hardware and the graphical software you want to run. Besides that, Xorg is also fully network-aware, meaning you are able to run an application on one system while viewing it on a different one.

Installing Xorg

Before you can install Xorg, you need to prepare your system for it. First, we'll set up the kernel to support input devices and video cards. Then we'll prepare /etc/portage/make.conf so that the right drivers and Xorg packages are built and installed.

Input driver support

By default, Xorg uses evdev[1], a generic input driver. You'll need to activate support for evdev by making a change to your kernel configuration. Read the Kernel Configuration Guide if you don't know how to setup your kernel.

Kernel configurationEnabling evdev in the kernel

Device Drivers --->
  Input device support --->
  <*>  Event interface

Kernel modesetting

Modern open-source video drivers rely on kernel modesetting (KMS). KMS provides an improved graphical boot with less flickering, faster user switching, a built-in framebuffer console, seamless switching from the console to Xorg, and other features. KMS conflicts with legacy framebuffer drivers, which must remain disabled in your kernel configuration.

First, prepare your kernel for KMS. You need to do this step regardless of which Xorg video driver you're using.

Kernel configurationConfiguring framebuffers

Device Drivers --->
  Graphics support --->
    Support for frame buffer devices --->
    ## (Disable all drivers, including VGA, Intel, nVidia, and ATI)
 
    ## (Further down, enable basic console support. KMS uses this.)
    Console display driver support --->
      <*>  Framebuffer Console Support

Next, configure your kernel to use the proper KMS driver for your video card. Intel, nVidia, and AMD/ATI are the most common cards, so follow code listing for your card below.

For Intel cards[2]:

Kernel configurationIntel settings

Device Drivers --->
  Graphics support --->
    /dev/agpgart (AGP Support) --->
    <*>  Intel 440LX/BX/GX, I8xx and E7x05 chipset support
    Direct Rendering Manager (XFree86 4.1.0 and higher DRI support) --->
    <*>  Intel 8xx/9xx/G3x/G4x/HD Graphics
    [*]    Enable modesetting on intel by default

For nVidia cards:

Kernel configurationnVidia settings

Device Drivers --->
  Graphics support --->
    Direct Rendering Manager (XFree86 4.1.0 and higher DRI support) --->
    <*>    Nouveau (nVidia) cards

For newer AMD/ATI cards (RadeonHD 2000 and up), you will need to emerge x11-drivers/radeon-ucode or sys-kernel/linux-firmware. Once you have installed one of these packages, configure your kernel as detailed in the firmware section of Radeon page:

Kernel configurationAMD/ATI settings

## (Setup the kernel to use the radeon-ucode firmware)
Device Drivers --->
  Generic Driver Options --->
  [*]  Include in-kernel firmware blobs in kernel binary
  ## # ATI card specific, (see Radeon page for details of firmware to include)
   (radeon/<YOUR-MODEL>.bin ...)
  ## # all:
   (/lib/firmware/) Firmware blobs root directory
 
## (Enable Radeon KMS support)
Device Drivers --->
  Graphics support --->
  <*>  Direct Rendering Manager --->
  <*>    ATI Radeon
  [*]      Enable modesetting on radeon by default
  [ ]      Enable userspace modesetting on radeon (DEPRECATED)
Note
Old Radeon cards (X1900 series and older) don't need the x11-drivers/radeon-ucode package or any firmware configuration. Just enable the Direct Rendering Manager and ATI Radeon modesetting.
Note
Linux kernel >= 3.9 does not have the Enable modesetting on radeon by default anymore as it is already implied by default.

Now that you're done setting up KMS, continue with preparing /etc/portage/make.conf in the next section.

make.conf configuration

Now that your kernel is prepared, you have to configure two important variables in the /etc/portage/make.conf file before you can install Xorg.

The first variable is VIDEO_CARDS. This is used to set the video drivers that you intend to use and is usually based on the kind of video card you have. The most common settings are nouveau for nVidia cards or radeon for ATI cards. Both have actively developed, well-supported open-source drivers.

Note
You may also try the proprietary drivers from nVidia and AMD/ATI, nvidia and fglrx respectively. However, setting up the proprietary drivers is beyond the scope of this guide. Please read the Gentoo Linux nVidia Guide and Gentoo Linux ATI FAQ. If you don't know which drivers you should choose, refer to these guides for more information.

The intel driver may be used for desktops or laptops with common Intel integrated graphics chipsets.

Note
VIDEO_CARDS may contain more than one driver, each separated with a space.

The second variable is INPUT_DEVICES and is used to determine which drivers are to be built for input devices. In most cases setting it to evdev[1] should work just fine. If you use alternative input devices, such as a Synaptics touchpad for a laptop, be sure to add it to INPUT_DEVICES.

Now you should decide which drivers you will use and add necessary settings to the /etc/portage/make.conf file:

CodeSample make.conf entries

## (For mouse, keyboard, and Synaptics touchpad support)
INPUT_DEVICES="evdev synaptics"
## (For nVidia cards)
VIDEO_CARDS="nouveau"
## (For AMD/ATI cards)
VIDEO_CARDS="radeon"

If the suggested settings don't work for you, you should run emerge -pv xorg-drivers, check all the options available and choose those which apply to your system. This example is for a system with a keyboard, mouse, Synaptics touchpad, and a Radeon video card.

root # emerge -pv xorg-drivers
 
These are the packages that would be merged, in order:
 
Calculating dependencies... done!
[ebuild   R   ]  x11-base/xorg-drivers-1.9  INPUT_DEVICES="evdev synaptics
-acecad -aiptek -elographics% -fpit% -joystick -keyboard -mouse -penmount -tslib
-virtualbox -vmmouse -void -wacom"
VIDEO_CARDS="radeon -apm -ark -ast -chips -cirrus -dummy -epson -fbdev -fglrx
(-geode) -glint -i128 (-i740) (-impact) -intel -mach64 -mga -neomagic (-newport)
-nouveau -nv -nvidia -r128 -rendition -s3 -s3virge -savage -siliconmotion -sis
-sisusb (-sunbw2) (-suncg14) (-suncg3) (-suncg6) (-sunffb) (-sunleo) (-suntcx)
-tdfx -tga -trident -tseng -v4l -vesa -via -virtualbox -vmware (-voodoo) (-xgi)"
0 kB

After setting all the necessary variables you can install the Xorg package.

First of all, make sure udev is in your USE flags:

root # echo "x11-base/xorg-server udev" >> /etc/portage/package.use

Next, install Xorg:

root # emerge --ask xorg-server
Note
You could install the xorg-x11 metapackage instead of the more lightweight xorg-server. Functionally, xorg-x11 and xorg-server are the same. However, xorg-x11 brings in many more packages that you probably don't need, such as a huge assortment of fonts in many different languages. They're not necessary for a working desktop.

When the installation is finished, you will need to re-initialise some environment variables before you continue:

root # env-update
root #
source /etc/profile

For nVidia users

It might be beneficial to run nvidia-xconfig in order to generate a working xorg.conf for the selected graphics card. If this is not done, then the xorg.conf file will need to be created manually as described below. If not, then a "No screens found" error will most likely pop up when attempting to start X.

Also the nvidia driver will only work after a reboot.

root # nvidia-xconfig

It is possible (and probably recommended) to set the OpenGL renderer to the hardware renderer instead of a software renderer:

root # eselect opengl set nvidia

Configuring Xorg

The X server is designed to work out-of-the-box, with no need to manually edit Xorg's configuration files. It should detect and configure devices such as displays, keyboards, and mice.

You should first try using startx without editing any configuration files. If Xorg won't start, or there's some other problem, then you'll need to manually configure Xorg as shown in the next section.

Note
Do not forget to restart the system before using startx in order to boot the new kernel if changes have been made to it.

The xorg.conf.d directory

Note
Configuring files in xorg.conf.d should be seen as a "last resort" option. It's really desirable to run without any special configuration if possible. If you still can't get a working configuration, then read on.

The configuration files of Xorg are stored in /etc/X11/xorg.conf.d/. Each file is given a unique name and ends in .conf. If the filenames start with a number, then Xorg will read the files in numeric order. 10-evdev.conf will be read before 20-synaptics.conf, and so on. You don't have to give them numbers, but it may help you organize them.

Note
Xorg provides example configurations in /usr/share/doc/xorg-server-${version}/xorg.conf.example.bz2. You can use these to create your own configuration files in /etc/X11/xorg.conf.d/. The examples are heavily commented, but if you are in need of more documentation regarding the syntax, read man xorg.conf. Other examples can be found in the Resources chapter at the end of this guide.

Using startx

Now try startx to start up your X server. startx is a script that executes an X session; that is, it starts the X server and some graphical applications on top of it. It decides which applications to run using the following logic:

  • If a file named .xinitrc exists in the home directory, it will execute the commands listed there.
  • Otherwise, it will read the value of the XSESSION variable and will execute one of the sessions available in /etc/X11/Sessions/ accordingly. You can set the value of XSESSION in /etc/env.d/90xsession to make it a default for all the users on the system. For example, as root, run echo XSESSION="Xfce4" > /etc/env.d/90xsession. This will create the 90xsession file and set the default X session to Xfce. Remember to run env-update after changing 90xsession.
user $ startx

If you haven't yet installed a window manager, all you'll see is a black screen. Since this can also be a sign that something's wrong, you may want to emerge x11-wm/twm and x11-terms/xterm only to test X.

Once those two programs are installed, run startx again. A few xterm windows should appear, making it easier to verify that X is working correctly. Once you're satisfied with the results, run emerge --unmerge twm xterm as root to get rid of the testing packages. You won't need them once you've setup a proper desktop environment.

Tweaking X settings

Setting your Resolution

If you feel that the screen resolution is wrong, you will need to check two sections in your xorg.conf.d configuration. First of all, you have the Screen section which lists the resolutions that your X server will run at. This section might not list any resolutions at all. If this is the case, Xorg will estimate the resolutions based on the information in the second section, Monitor.

Now let us change the resolution. In the next example from /etc/X11/xorg.conf.d/40-monitor.conf we add the PreferredMode line so that our X server starts at 1440x900 by default. The Option in the Device section must match the name of your monitor (DVI-0), which can be obtained by running xrandr. You'll need to emerge xrandr just long enough to get this information. The argument after the monitor name (in the Device section) must match the Identifier in the Monitor section.

root # nano -w /etc/X11/xorg.conf.d/40-monitor.conf
Section "Device"
  Identifier  "RadeonHD 4550"
  Option      "Monitor-DVI-0" "DVI screen"
EndSection
Section "Monitor"
  Identifier  "DVI screen"
  Option      "PreferredMode" "1440x900"
EndSection

Run X (startx) to discover it uses the resolution you want.

Multiple monitors

You can configure more than one monitor in /etc/X11/xorg.conf.d/. All you have to do is give each monitor an identifer, then list its physical position, such as "RightOf" or "Above" another monitor. The following example shows how to configure a DVI and a VGA monitor, with the VGA monitor as the right-hand screen:

root # nano -w /etc/X11/xorg.conf.d/40-monitor.conf
Section "Device"
  Identifier "RadeonHD 4550"
  Option     "Monitor-DVI-0" "DVI screen"
  Option     "Monitor-VGA-0" "VGA screen"
EndSection
Section "Monitor"
  Identifier "DVI screen"
EndSection
Section "Monitor"
  Identifier "VGA screen"
  Option     "RightOf" "DVI screen"
EndSection

Configuring your keyboard

To setup X to use an international keyboard, you just have to create the appropriate config file in /etc/X11/xorg.conf.d/. This example features a Czech keyboard layout:

root # nano -w /etc/X11/xorg.conf.d/30-keyboard.conf
Section "InputClass"
        Identifier "keyboard-all"
        Driver "evdev"
        Option "XkbLayout" "us,cz"
        Option "XkbModel" "logitech_g15"
        Option "XkbRules" "xorg"
        Option "XkbOptions" "grp:alt_shift_toggle,grp:switch,grp_led:scroll,compose:rwin,terminate:ctrl_alt_bksp"
        Option "XkbVariant" ",qwerty"
        MatchIsKeyboard "on"
EndSection

The "terminate" command (terminate:ctrl_alt_bksp) lets you kill the X session by using the Ctrl-Alt-Backspace key combination. This will, however, make X exit disgracefully -- something that you might not always want. It can be useful when programs have frozen your display entirely, or when you're configuring and tweaking your Xorg environment. Be careful when killing your desktop with this key combination -- most programs really don't like it when you end them this way, and you may lose some (or all) of what you were working on.

Finishing up

Run startx and be happy about the result. Congratulations, you now (hopefully) have a working Xorg on your system. The next step is to install a useful window manager or desktop environment such as KDE, GNOME, or Xfce, but that's not part of this guide. Information on installing these desktop environments can be found in our Gentoo Desktop Documentation Resources .

Resources

Creating and editing config files

First of all, man xorg.conf and man evdev[1] provide quick yet complete references about the syntax used by these configuration files. Be sure to have them open on a terminal when you edit your configuration files!

There are also many online resources on editing config files in /etc/X11/. We only list few of them here; be sure to use your favorite search engine to find more.

Other resources

More information about installing and configuring various graphical desktop environments and applications can be found in the Gentoo Desktop Documentation Resources section of our documentation.

If you're upgrading to xorg-server 1.9 from an earlier version, then be sure to read the migration guide.

X.org provides many FAQs on their website, in addition to their other documentation.

Acknowledgements

We would like to thank the following authors and editors for their contributions to this guide:

  • swift
  • nightmorph

References