xorg.conf

xorg.conf(5)                  File Formats Manual                 xorg.conf(5)



NAME
       xorg.conf, xorg.conf.d - configuration files for Xorg X server

INTRODUCTION
       Xorg supports several mechanisms for supplying/obtaining configuration
       and run-time parameters: command line options, environment variables,
       the xorg.conf and xorg.conf.d configuration files, auto-detection, and
       fallback defaults. When the same information is supplied in more than
       one way, the highest precedence mechanism is used. The list of
       mechanisms is ordered from highest precedence to lowest. Note that not
       all parameters can be supplied via all methods. The available command
       line options and environment variables (and some defaults) are
       described in the Xserver(1) and Xorg(1) manual pages. Most
       configuration file parameters, with their defaults, are described
       below. Driver and module specific configuration parameters are
       described in the relevant driver or module manual page.

DESCRIPTION
       Xorg uses a configuration file called xorg.conf and files ending in the
       suffix .conf from the directory xorg.conf.d for its initial setup.  The
       xorg.conf configuration file is searched for in the following places
       when the server is started as a normal user:

           /etc/X11/<cmdline>
           /usr/etc/X11/<cmdline>
           /etc/X11/$XORGCONFIG
           /usr/etc/X11/$XORGCONFIG
           /etc/X11/xorg.conf
           /etc/xorg.conf
           /usr/etc/X11/xorg.conf.<hostname>
           /usr/etc/X11/xorg.conf
           /usr/lib/X11/xorg.conf.<hostname>
           /usr/lib/X11/xorg.conf

       where <cmdline> is a relative path (with no “..” components) specified
       with the -config command line option, $XORGCONFIG is the relative path
       (with no “..” components) specified by that environment variable, and
       <hostname> is the machine's hostname as reported by gethostname(3).

       When the Xorg server is started by the “root” user, the config file
       search locations are as follows:

           <cmdline>
           /etc/X11/<cmdline>
           /usr/etc/X11/<cmdline>
           $XORGCONFIG
           /etc/X11/$XORGCONFIG
           /usr/etc/X11/$XORGCONFIG
           /etc/X11/xorg.conf
           /etc/xorg.conf
           /usr/etc/X11/xorg.conf.<hostname>
           /usr/etc/X11/xorg.conf
           /usr/lib/X11/xorg.conf.<hostname>
           /usr/lib/X11/xorg.conf

       where <cmdline> is the path specified with the -config command line
       option (which may be absolute or relative), $XORGCONFIG is the path
       specified by that environment variable (absolute or relative), $HOME is
       the path specified by that environment variable (usually the home
       directory), and <hostname> is the machine's hostname as reported by
       gethostname(3).

       Additional configuration files are searched for in the following
       directories when the server is started as a normal user:

           /etc/X11/<cmdline>
           /etc/X11/<cmdline>
           /etc/X11/xorg.conf.d
           /etc/X11/xorg.conf.d

       where <cmdline> is a relative path (with no “..” components) specified
       with the -configdir command line option.

       When the Xorg server is started by the “root” user, the config
       directory search locations are as follows:

           <cmdline>
           /etc/X11/<cmdline>
           /etc/X11/<cmdline>
           /etc/X11/xorg.conf.d
           /etc/X11/xorg.conf.d

       where <cmdline> is the path specified with the -configdir command line
       option (which may be absolute or relative).

       Finally, configuration files will also be searched for in a directory
       reserved for system use.  This is to separate configuration files from
       the vendor or 3rd party packages from those of local administration.
       These files are found in the following directory:

           /usr/share/X11/xorg.conf.d

       The xorg.conf and xorg.conf.d files are composed of a number of
       sections which may be present in any order, or omitted to use default
       configuration values.  Each section has the form:

           Section  "SectionName"
               SectionEntry
               ...
           EndSection

       The section names are:

           Files          File pathnames
           ServerFlags    Server flags
           Module         Dynamic module loading
           Extensions     Extension enabling
           InputDevice    Input device description
           InputClass     Input class description
           OutputClass    Output class description
           Device         Graphics device description
           VideoAdaptor   Xv video adaptor description
           Monitor        Monitor description
           Modes          Video modes descriptions
           Screen         Screen configuration
           ServerLayout   Overall layout
           DRI            DRI-specific configuration
           Vendor         Vendor-specific configuration

       The following obsolete section names are still recognised for
       compatibility purposes.  In new config files, the InputDevice section
       should be used instead.

           Keyboard       Keyboard configuration
           Pointer        Pointer/mouse configuration

       The old XInput section is no longer recognised.

       The ServerLayout sections are at the highest level.  They bind together
       the input and output devices that will be used in a session.  The input
       devices are described in the InputDevice sections.  Output devices
       usually consist of multiple independent components (e.g., a graphics
       board and a monitor).  These multiple components are bound together in
       the Screen sections, and it is these that are referenced by the
       ServerLayout section.  Each Screen section binds together a graphics
       board and a monitor.  The graphics boards are described in the Device
       sections, and the monitors are described in the Monitor sections.

       Config file keywords are case-insensitive, and “_” characters are
       ignored.  Most strings (including Option names) are also case-
       insensitive, and insensitive to white space and “_” characters.

       Each config file entry usually takes up a single line in the file.
       They consist of a keyword, which is possibly followed by one or more
       arguments, with the number and types of the arguments depending on the
       keyword.  The argument types are:

           Integer     an integer number in decimal, hex or octal
           Real        a floating point number
           String      a string enclosed in double quote marks (")

       Note: hex integer values must be prefixed with “0x”, and octal values
       with “0”.

       A special keyword called Option may be used to provide free-form data
       to various components of the server.  The Option keyword takes either
       one or two string arguments.  The first is the option name, and the
       optional second argument is the option value.  Some commonly used
       option value types include:

           Integer     an integer number in decimal, hex or octal
           Real        a floating point number
           String      a sequence of characters
           Boolean     a boolean value (see below)
           Frequency   a frequency value (see below)

       Note that all Option values, not just strings, must be enclosed in
       quotes.

       Boolean options may optionally have a value specified.  When no value
       is specified, the option's value is TRUE.  The following boolean option
       values are recognised as TRUE:

           1, on, true, yes

       and the following boolean option values are recognised as FALSE:

           0, off, false, no

       If an option name is prefixed with "No", then the option value is
       negated.

       Example: the following option entries are equivalent:

           Option "Accel"   "Off"
           Option "NoAccel"
           Option "NoAccel" "On"
           Option "Accel"   "false"
           Option "Accel"   "no"

       Frequency option values consist of a real number that is optionally
       followed by one of the following frequency units:

           Hz, k, kHz, M, MHz

       When the unit name is omitted, the correct units will be determined
       from the value and the expectations of the appropriate range of the
       value.  It is recommended that the units always be specified when using
       frequency option values to avoid any errors in determining the value.

FILES SECTION
       The Files section is used to specify some path names required by the
       server.  Some of these paths can also be set from the command line (see
       Xserver(1) and Xorg(1)).  The command line settings override the values
       specified in the config file.  The Files section is optional, as are
       all of the entries that may appear in it.

       The entries that can appear in this section are:

       FontPath "path"
              sets the search path for fonts.  This path is a comma separated
              list of font path elements which the Xorg server searches for
              font databases.  Multiple FontPath entries may be specified, and
              they will be concatenated to build up the fontpath used by the
              server.  Font path elements can be absolute directory paths,
              catalogue directories or a font server identifier. The formats
              of the later two are explained below:

              Catalogue directories:

                  Catalogue directories can be specified using the prefix
                  catalogue: before the directory name. The directory can then
                  be populated with symlinks pointing to the real font
                  directories, using the following syntax in the symlink name:

                      <identifier>:[attribute]:pri=<priority>

                  where <identifier> is an alphanumeric identifier,
                  [attribute] is an attribute which will be passed to the
                  underlying FPE and <priority> is a number used to order the
                  fontfile FPEs. Examples:

                      75dpi:unscaled:pri=20 -> /usr/share/X11/fonts/75dpi
                      gscript:pri=60 -> /usr/share/fonts/default/ghostscript
                      misc:unscaled:pri=10 -> /usr/share/X11/fonts/misc

              Font server identifiers:

                  Font server identifiers have the form:

                      <trans>/<hostname>:<port-number>

                  where <trans> is the transport type to use to connect to the
                  font server (e.g., unix for UNIX-domain sockets or tcp for a
                  TCP/IP connection), <hostname> is the hostname of the
                  machine running the font server, and <port-number> is the
                  port number that the font server is listening on (usually
                  7100).

              When this entry is not specified in the config file, the server
              falls back to the compiled-in default font path, which contains
              the following font path elements (which can be set inside a
              catalogue directory):

                  /usr/share/fonts/X11/misc/
                  /usr/share/fonts/X11/TTF/
                  /usr/share/fonts/X11/OTF/
                  /usr/share/fonts/X11/Type1/
                  /usr/share/fonts/X11/100dpi/
                  /usr/share/fonts/X11/75dpi/

              Font path elements that are found to be invalid are removed from
              the font path when the server starts up.

       ModulePath "path"
              sets the search path for loadable Xorg server modules.  This
              path is a comma separated list of directories which the Xorg
              server searches for loadable modules loading in the order
              specified.  Multiple ModulePath entries may be specified, and
              they will be concatenated to build the module search path used
              by the server.  The default module path is

                  lib/xorg/modules

       XkbDir "path"
              sets the base directory for keyboard layout files.  The -xkbdir
              command line option can be used to override this.  The default
              directory is

                  /usr/share/X11/xkb

SERVERFLAGS SECTION
       In addition to options specific to this section (described below), the
       ServerFlags section is used to specify some global Xorg server options.
       All of the entries in this section are Options, although for
       compatibility purposes some of the old style entries are still
       recognised.  Those old style entries are not documented here, and using
       them is discouraged.  The ServerFlags section is optional, as are the
       entries that may be specified in it.

       Options specified in this section (with the exception of the
       "DefaultServerLayout" Option) may be overridden by Options specified in
       the active ServerLayout section.  Options with command line equivalents
       are overridden when their command line equivalent is used.  The options
       recognised by this section are:

       Option "Debug"  "string"
              This comma-separated list provides a way to control various
              debugging switches from the config file.  At the moment the only
              defined value is dmabuf_capable which instructs glamor to enable
              some unstable buffer management code.

       Option "DefaultServerLayout"  "layout-id"
              This specifies the default ServerLayout section to use in the
              absence of the -layout command line option.

       Option "NoTrapSignals"  "boolean"
              This prevents the Xorg server from trapping a range of
              unexpected fatal signals and exiting cleanly.  Instead, the Xorg
              server will die and drop core where the fault occurred.  The
              default behaviour is for the Xorg server to exit cleanly, but
              still drop a core file.  In general you never want to use this
              option unless you are debugging an Xorg server problem and know
              how to deal with the consequences.

       Option "DontVTSwitch"  "boolean"
              This disallows the use of the Ctrl+Alt+Fn sequence (where Fn
              refers to one of the numbered function keys).  That sequence is
              normally used to switch to another "virtual terminal" on
              operating systems that have this feature.  When this option is
              enabled, that key sequence has no special meaning and is passed
              to clients.  Default: off.

       Option "DontZap"  "boolean"
              This disallows the use of the Terminate_Server XKB action
              (usually on Ctrl+Alt+Backspace, depending on XKB options).  This
              action is normally used to terminate the Xorg server.  When this
              option is enabled, the action has no effect.  Default: off.

       Option "DontZoom"  "boolean"
              This disallows the use of the Ctrl+Alt+Keypad-Plus and
              Ctrl+Alt+Keypad-Minus sequences.  These sequences allows you to
              switch between video modes.  When this option is enabled, those
              key sequences have no special meaning and are passed to clients.
              Default: off.

       Option "DisableVidModeExtension"  "boolean"
              This disables the parts of the VidMode extension used by the
              xvidtune client that can be used to change the video modes.
              Default: the VidMode extension is enabled.

       Option "AllowNonLocalXvidtune"  "boolean"
              This allows the xvidtune client (and other clients that use the
              VidMode extension) to connect from another host.  Default: off.

       Option "AllowMouseOpenFail"  "boolean"
              This tells the mousedrv(4) and vmmouse(4) drivers to not report
              failure if the mouse device can't be opened/initialised.  It has
              no effect on the evdev(4) or other drivers.  Default: false.

       Option "BlankTime"  "time"
              sets the inactivity timeout for the blank phase of the
              screensaver.  time is in minutes.  This is equivalent to the
              Xorg server's -s flag, and the value can be changed at run-time
              with xset(1).  Default: 10 minutes.

       Option "StandbyTime"  "time"
              sets the inactivity timeout for the standby phase of DPMS mode.
              time is in minutes, and the value can be changed at run-time
              with xset(1).  Default: 10 minutes.  This is only suitable for
              VESA DPMS compatible monitors, and may not be supported by all
              video drivers.  It is only enabled for screens that have the
              "DPMS" option set (see the MONITOR section below).

       Option "SuspendTime"  "time"
              sets the inactivity timeout for the suspend phase of DPMS mode.
              time is in minutes, and the value can be changed at run-time
              with xset(1).  Default: 10 minutes.  This is only suitable for
              VESA DPMS compatible monitors, and may not be supported by all
              video drivers.  It is only enabled for screens that have the
              "DPMS" option set (see the MONITOR section below).

       Option "OffTime"  "time"
              sets the inactivity timeout for the off phase of DPMS mode.
              time is in minutes, and the value can be changed at run-time
              with xset(1).  Default: 10 minutes.  This is only suitable for
              VESA DPMS compatible monitors, and may not be supported by all
              video drivers.  It is only enabled for screens that have the
              "DPMS" option set (see the MONITOR section below).

       Option "MaxClients"  "integer"
              Set the maximum number of clients allowed to connect to the X
              server.  Acceptable values are 64, 128, 256 or 512.

       Option "NoPM"  "boolean"
              Disables something to do with power management events.  Default:
              PM enabled on platforms that support it.

       Option "Xinerama"  "boolean"
              enable or disable XINERAMA extension.  Default is disabled.

       Option "IndirectGLX" "boolean"
              enable or disable indirect GLX contexts. Indirect GLX contexts
              are disabled by default.

       Option "DRI2" "boolean"
              enable or disable DRI2. DRI2 is disabled by default.

       Option "GlxVisuals" "string"
              This option controls how many GLX visuals the GLX modules sets
              up.  The default value is typical, which will setup up a typical
              subset of the GLXFBConfigs provided by the driver as GLX
              visuals.  Other options are minimal, which will set up the
              minimal set allowed by the GLX specification and all which will
              setup GLX visuals for all GLXFBConfigs.

       Option "UseDefaultFontPath" "boolean"
              Include the default font path even if other paths are specified
              in xorg.conf. If enabled, other font paths are included as well.
              Enabled by default.

       Option "IgnoreABI" "boolean"
              Allow modules built for a different, potentially incompatible
              version of the X server to load. Disabled by default.

       Option "AutoAddDevices" "boolean"
              If this option is disabled, then no devices will be added from
              the HAL or udev backends. Enabled by default.

       Option "AutoEnableDevices" "boolean"
              If this option is disabled, then the devices will be added (and
              the DevicePresenceNotify event sent), but not enabled, thus
              leaving policy up to the client.  Enabled by default.

       Option "AutoAddGPU" "boolean"
              If this option is disabled, then no GPU devices will be added
              from the udev backend. Enabled by default. (May need to be
              disabled to setup Xinerama).

       Option "AutoBindGPU"  "boolean"
              If enabled then secondary GPUs will be automatically set up as
              output-sinks and offload-sources. Making e.g. laptop outputs
              connected only to the secondary GPU directly available for use
              without needing to run "xrandr --setprovideroutputsource".
              Enabled by default.

       Option "Log" "string"
              This option controls whether the log is flushed and/or synced to
              disk after each message.  Possible values are flush or sync.
              Unset by default.

MODULE SECTION
       The Module section is used to specify which Xorg server modules should
       be loaded.  This section is ignored when the Xorg server is built in
       static form.  The type of modules normally loaded in this section are
       Xorg server extension modules.  Most other module types are loaded
       automatically when they are needed via other mechanisms.  The Module
       section is optional, as are all of the entries that may be specified in
       it.

       Entries in this section may be in two forms.  The first and most
       commonly used form is an entry that uses the Load keyword, as described
       here:

       Load  "modulename"
              This instructs the server to load the module called modulename.
              The module name given should be the module's standard name, not
              the module file name.  The standard name is case-sensitive, and
              does not include the “lib” or “cyg” prefixes, or the “.so” or
              “.dll” suffixes.

              Example: the DRI extension module can be loaded with the
              following entry:

                  Load "dri"

       Disable  "modulename"
              This instructs the server to not load the module called
              modulename.  Some modules are loaded by default in the server,
              and this overrides that default. If a Load instruction is given
              for the same module, it overrides the Disable instruction and
              the module is loaded. The module name given should be the
              module's standard name, not the module file name. As with the
              Load instruction, the standard name is case-sensitive, and does
              not include the "lib" prefix, or the ".a", ".o", or ".so"
              suffixes.

       The second form of entry is a SubSection, with the subsection name
       being the module name, and the contents of the SubSection being Options
       that are passed to the module when it is loaded.

       Example: the extmod module (which contains a miscellaneous group of
       server extensions) can be loaded, with the XFree86-DGA extension
       disabled by using the following entry:

           SubSection "extmod"
              Option  "omit XFree86-DGA"
           EndSubSection

       Modules are searched for in each directory specified in the ModulePath
       search path, and in the drivers, extensions, input, internal, and
       multimedia subdirectories of each of those directories.  In addition to
       this, operating system specific subdirectories of all the above are
       searched first if they exist.

       To see what extension modules are available, check the extensions
       subdirectory under:

           lib/xorg/modules

       The “extmod”, “dbe”, “dri”, “dri2”, “glx”, and “record” extension
       modules are loaded automatically, if they are present, unless disabled
       with "Disable" entries.  It is recommended that at very least the
       “extmod” extension module be loaded.  If it isn't, some commonly used
       server extensions (like the SHAPE extension) will not be available.

EXTENSIONS SECTION
       The Extensions section is used to specify which X11 protocol extensions
       should be enabled or disabled.  The Extensions section is optional, as
       are all of the entries that may be specified in it.

       Entries in this section are listed as Option statements with the name
       of the extension as the first argument, and a boolean value as the
       second.  The extension name is case-sensitive, and matches the form
       shown in the output of "Xorg -extension ?".

              Example: the MIT-SHM extension can be disabled with the
              following entry:

                  Section "Extensions"
                      Option "MIT-SHM" "Disable"
                  EndSection

INPUTDEVICE SECTION
       The config file may have multiple InputDevice sections.  Recent X
       servers employ HAL or udev backends for input device enumeration and
       input hotplugging. It is usually not necessary to provide InputDevice
       sections in the xorg.conf if hotplugging is in use (i.e. AutoAddDevices
       is enabled). If hotplugging is enabled, InputDevice sections using the
       mouse, kbd and vmmouse driver will be ignored.

       If hotplugging is disabled, there will normally be at least two: one
       for the core (primary) keyboard and one for the core pointer.  If
       either of these two is missing, a default configuration for the missing
       ones will be used. In the absence of an explicitly specified core input
       device, the first InputDevice marked as CorePointer (or CoreKeyboard)
       is used.  If there is no match there, the first InputDevice that uses
       the “mouse” (or “kbd”) driver is used.  The final fallback is to use
       built-in default configurations.  Currently the default configuration
       may not work as expected on all platforms.

       InputDevice sections have the following format:

           Section "InputDevice"
               Identifier "name"
               Driver     "inputdriver"
               options
               ...
           EndSection

       The Identifier and Driver entries are required in all InputDevice
       sections.  All other entries are optional.

       The Identifier entry specifies the unique name for this input device.
       The Driver entry specifies the name of the driver to use for this input
       device.  When using the loadable server, the input driver module
       "inputdriver" will be loaded for each active InputDevice section.  An
       InputDevice section is considered active if it is referenced by an
       active ServerLayout section, if it is referenced by the -keyboard or
       -pointer command line options, or if it is selected implicitly as the
       core pointer or keyboard device in the absence of such explicit
       references.  The most commonly used input drivers are evdev(4) on Linux
       systems, and kbd(4) and mousedrv(4) on other platforms.

       InputDevice sections recognise some driver-independent Options, which
       are described here.  See the individual input driver manual pages for a
       description of the device-specific options.

       Option "AutoServerLayout"  "boolean"
              Always add the device to the ServerLayout section used by this
              instance of the server. This affects implied layouts as well as
              explicit layouts specified in the configuration and/or on the
              command line.

       Option "CorePointer"
              Deprecated, see Floating

       Option "CoreKeyboard"
              Deprecated, see Floating

       Option "AlwaysCore"  "boolean"
              Deprecated, see Floating

       Option "SendCoreEvents"  "boolean"
              Deprecated, see Floating


       Option "Floating"  "boolean"
              When enabled, the input device is set up floating and does not
              report events through any master device or control a cursor. The
              device is only available to clients using the X Input Extension
              API. This option is disabled by default.  The options
              CorePointer, CoreKeyboard, AlwaysCore, and SendCoreEvents, are
              the inverse of option Floating (i.e.  SendCoreEvents "on" is
              equivalent to Floating "off" ).

              This option controls the startup behavior only, a device may be
              reattached or set floating at runtime.

       Option "TransformationMatrix" "a b c d e f g h i"
              Specifies the 3x3 transformation matrix for absolute input
              devices. The input device will be bound to the area given in the
              matrix.  In most configurations, "a" and "e" specify the width
              and height of the area the device is bound to, and "c" and "f"
              specify the x and y offset of the area.  The value range is 0 to
              1, where 1 represents the width or height of all root windows
              together, 0.5 represents half the area, etc. The values
              represent a 3x3 matrix, with the first, second and third group
              of three values representing the first, second and third row of
              the matrix, respectively.  The identity matrix is "1 0 0 0 1 0 0
              0 1".

   POINTER ACCELERATION
       For pointing devices, the following options control how the pointer is
       accelerated or decelerated with respect to physical device motion. Most
       of these can be adjusted at runtime, see the xinput(1) man page for
       details. Only the most important acceleration options are discussed
       here.

       Option "AccelerationProfile"  "integer"
              Select the profile. In layman's terms, the profile constitutes
              the "feeling" of the acceleration. More formally, it defines how
              the transfer function (actual acceleration as a function of
              current device velocity and acceleration controls) is
              constructed. This is mainly a matter of personal preference.

              0      classic (mostly compatible)
             -1      none (only constant deceleration is applied)
              1      device-dependent
              2      polynomial (polynomial function)
              3      smooth linear (soft knee, then linear)
              4      simple (normal when slow, otherwise accelerated)
              5      power (power function)
              6      linear (more speed, more acceleration)
              7      limited (like linear, but maxes out at threshold)

       Option "ConstantDeceleration"  "real"
              Makes the pointer go deceleration times slower than normal. Most
              useful for high-resolution devices. A value between 0 and 1 will
              speed up the pointer.

       Option "AdaptiveDeceleration"  "real"
              Allows to actually decelerate the pointer when going slow. At
              most, it will be adaptive deceleration times slower. Enables
              precise pointer placement without sacrificing speed.

       Option "AccelerationScheme"  "string"
              Selects the scheme, which is the underlying algorithm.

              predictable   default algorithm (behaving more predictable)
              lightweight   old acceleration code (as specified in the X protocol spec)
              none          no acceleration or deceleration

       Option "AccelerationNumerator"  "integer"

       Option "AccelerationDenominator"  "integer"
              Set numerator and denominator of the acceleration factor. The
              acceleration factor is a rational which, together with
              threshold, can be used to tweak profiles to suit the users
              needs. The simple and limited profiles use it directly (i.e.
              they accelerate by the factor), for other profiles it should
              hold that a higher acceleration factor leads to a faster
              pointer. Typically, 1 is unaccelerated and values up to 5 are
              sensible.

       Option "AccelerationThreshold"  "integer"
              Set the threshold, which is roughly the velocity (usually device
              units per 10 ms) required for acceleration to become effective.
              The precise effect varies with the profile however.


INPUTCLASS SECTION
       The config file may have multiple InputClass sections.  These sections
       are optional and are used to provide configuration for a class of input
       devices as they are automatically added. An input device can match more
       than one InputClass section. Each class can override settings from a
       previous class, so it is best to arrange the sections with the most
       generic matches first.

       InputClass sections have the following format:

           Section "InputClass"
               Identifier  "name"
               entries
               ...
               options
               ...
           EndSection

       The Identifier entry is required in all InputClass sections.  All other
       entries are optional.

       The Identifier entry specifies the unique name for this input class.
       The Driver entry specifies the name of the driver to use for this input
       device.  After all classes have been examined, the "inputdriver" module
       from the first Driver entry will be enabled when using the loadable
       server.

       When an input device is automatically added, its characteristics are
       checked against all InputClass sections. Each section can contain
       optional entries to narrow the match of the class. If none of the
       optional entries appear, the InputClass section is generic and will
       match any input device. If more than one of these entries appear, they
       all must match for the configuration to apply.

       There are two types of match entries used in InputClass sections. The
       first allows various tokens to be matched against attributes of the
       device. An entry can be constructed to match attributes from different
       devices by separating arguments with a '|' character. Multiple entries
       of the same type may be supplied to add multiple matching conditions on
       the same attribute. For example:

           Section "InputClass"
               Identifier   "My Class"
               # product string must contain example and
               # either gizmo or gadget
               MatchProduct "example"
               MatchProduct "gizmo|gadget"
               NoMatchDriver "drivername"
               ...
           EndSection

       MatchProduct  "matchproduct"
              This entry can be used to check if the substring "matchproduct"
              occurs in the device's product name.

       MatchVendor  "matchvendor"
              This entry can be used to check if the substring "matchvendor"
              occurs in the device's vendor name.

       MatchDevicePath "matchdevice"
              This entry can be used to check if the device file matches the
              "matchdevice" pathname pattern.

       MatchOS "matchos"
              This entry can be used to check if the operating system matches
              the case-insensitive "matchos" string. This entry is only
              supported on platforms providing the uname(2) system call.

       MatchPnPID "matchpnp"
              The device's Plug and Play (PnP) ID can be checked against the
              "matchpnp" shell wildcard pattern.

       MatchUSBID "matchusb"
              The device's USB ID can be checked against the "matchusb" shell
              wildcard pattern. The ID is constructed as lowercase hexadecimal
              numbers separated by a ':'. This is the same format as the
              lsusb(8) program.

       MatchDriver "matchdriver"
              Check the case-sensitive string "matchdriver" against the
              currently configured driver of the device. Ordering of sections
              using this entry is important since it will not match unless the
              driver has been set by the config backend or a previous
              InputClass section.

       MatchTag "matchtag"
              This entry can be used to check if tags assigned by the config
              backend matches the "matchtag" pattern. A match is found if at
              least one of the tags given in "matchtag" matches at least one
              of the tags assigned by the backend.

       MatchLayout "matchlayout"
              Check the case-sensitive string "matchlayout" against the
              currently active ServerLayout section. The empty string ""
              matches an implicit layout which appears if no named
              ServerLayout sections have been found.

       The above directives have equivalents for negative matching with the
       NoMatchProduct, NoMatchVendor, NoMatchDevicePath, NoMatchOS,
       NoMatchPnPID, NoMatchUSBID, NoMatchDriver, NoMatchTag, and
       NoMatchLayout directives. These NoMatch directives match if the
       subsequent match is not met by the device.

       The second type of entry is used to match device types. These entries
       take a boolean argument similar to Option entries.

       MatchIsKeyboard     "bool"

       MatchIsPointer      "bool"

       MatchIsJoystick     "bool"

       MatchIsTablet       "bool"

       MatchIsTabletPad    "bool"

       MatchIsTouchpad     "bool"

       MatchIsTouchscreen  "bool"

       When an input device has been matched to the InputClass section, any
       Option entries are applied to the device. One InputClass specific
       Option is recognized. See the InputDevice section above for a
       description of the remaining Option entries.

       Option "Ignore" "boolean"
              This optional entry specifies that the device should be ignored
              entirely, and not added to the server. This can be useful when
              the device is handled by another program and no X events should
              be generated.

OUTPUTCLASS SECTION
       The config file may have multiple OutputClass sections.  These sections
       are optional and are used to provide configuration for a class of
       output devices as they are automatically added.  An output device can
       match more than one OutputClass section.  Each class can override
       settings from a previous class, so it is best to arrange the sections
       with the most generic matches first.

       OutputClass sections have the following format:

           Section "OutputClass"
               Identifier  "name"
               entries
               ...
           EndSection

       The Identifier entry is required in all OutputClass sections.  All
       other entries are optional.

       The Identifier entry specifies the unique name for this output class.
       The Driver entry specifies the name of the driver to use for this
       output device.  After all classes have been examined, the
       "outputdriver" module from the first Driver entry will be enabled when
       using the loadable server.

       When an output device is automatically added, its characteristics are
       checked against all OutputClass sections.  Each section can contain
       optional entries to narrow the match of the class.  If none of the
       optional entries appear, the OutputClass section is generic and will
       match any output device.  If more than one of these entries appear,
       they all must match for the configuration to apply.

       The following list of tokens can be matched against attributes of the
       device.  An entry can be constructed to match attributes from different
       devices by separating arguments with a '|' character.

       For example:

           Section "OutputClass"
               Identifier   "My Class"
               # kernel driver must be either foo or bar
               MatchDriver "foo|bar"
               ...
           EndSection

       MatchDriver "matchdriver"
              Check the case-sensitive string "matchdriver" against the kernel
              driver of the device.

       When an output device has been matched to the OutputClass section, any
       Option entries are applied to the device. One OutputClass specific
       Option is recognized. See the Device section below for a description of
       the remaining Option entries.

       Option "PrimaryGPU" "boolean"
              This option specifies that the matched device should be treated
              as the primary GPU, replacing the selection of the GPU used as
              output by the firmware. If multiple output devices match an
              OutputClass section with the PrimaryGPU option set, the first
              one enumerated becomes the primary GPU.

       A OutputClass Section may contain ModulePath entries. When an output
       device matches an OutputClass section, any ModulePath entries in that
       OutputClass are pre-pended to the search path for loadable Xorg server
       modules. See ModulePath in the Files section for more info.

DEVICE SECTION
       The config file may have multiple Device sections.  There must be at
       least one, for the video card being used.

       Device sections have the following format:

           Section "Device"
               Identifier "name"
               Driver     "driver"
               entries
               ...
           EndSection

       The Identifier and Driver entries are required in all Device sections.
       All other entries are optional.

       The Identifier entry specifies the unique name for this graphics
       device.  The Driver entry specifies the name of the driver to use for
       this graphics device.  When using the loadable server, the driver
       module "driver" will be loaded for each active Device section.  A
       Device section is considered active if it is referenced by an active
       Screen section.

       Device sections recognise some driver-independent entries and Options,
       which are described here.  Not all drivers make use of these
       driver-independent entries, and many of those that do don't require
       them to be specified because the information is auto-detected.  See the
       individual graphics driver manual pages for further information about
       this, and for a description of the device-specific options.  Note that
       most of the Options listed here (but not the other entries) may be
       specified in the Screen section instead of here in the Device section.

       BusID  "bus-id"
              This specifies the bus location of the graphics card.  For
              PCI/AGP cards, the bus-id string has the form
              PCI:bus@domain:device:function (e.g., “PCI:1@0:0:0” might be
              appropriate for an AGP card). The "@domain" part can be left out
              for PCI domain 0. This field is usually optional in single-head
              configurations when using the primary graphics card.  In multi-
              head configurations, or when using a secondary graphics card in
              a single-head configuration, this entry is mandatory.  Its main
              purpose is to make an unambiguous connection between the device
              section and the hardware it is representing.  This information
              can usually be found by running the pciaccess tool scanpci.

       Screen  number
              This option is mandatory for cards where a single PCI entity can
              drive more than one display (i.e., multiple CRTCs sharing a
              single graphics accelerator and video memory).  One Device
              section is required for each head, and this parameter determines
              which head each of the Device sections applies to.  The legal
              values of number range from 0 to one less than the total number
              of heads per entity.  Most drivers require that the primary
              screen (0) be present.

       Chipset  "chipset"
              This usually optional entry specifies the chipset used on the
              graphics board.  In most cases this entry is not required
              because the drivers will probe the hardware to determine the
              chipset type.  Don't specify it unless the driver-specific
              documentation recommends that you do.

       Ramdac  "ramdac-type"
              This optional entry specifies the type of RAMDAC used on the
              graphics board.  This is only used by a few of the drivers, and
              in most cases it is not required because the drivers will probe
              the hardware to determine the RAMDAC type where possible.  Don't
              specify it unless the driver-specific documentation recommends
              that you do.

       DacSpeed  speed

       DacSpeed  speed-8 speed-16 speed-24 speed-32
              This optional entry specifies the RAMDAC speed rating (which is
              usually printed on the RAMDAC chip).  The speed is in MHz.  When
              one value is given, it applies to all framebuffer pixel sizes.
              When multiple values are given, they apply to the framebuffer
              pixel sizes 8, 16, 24 and 32 respectively.  This is not used by
              many drivers, and only needs to be specified when the speed
              rating of the RAMDAC is different from the defaults built in to
              driver, or when the driver can't auto-detect the correct
              defaults.  Don't specify it unless the driver-specific
              documentation recommends that you do.

       Clocks  clock ...
              specifies the pixel that are on your graphics board.  The clocks
              are in MHz, and may be specified as a floating point number.
              The value is stored internally to the nearest kHz.  The ordering
              of the clocks is important.  It must match the order in which
              they are selected on the graphics board.  Multiple Clocks lines
              may be specified, and each is concatenated to form the list.
              Most drivers do not use this entry, and it is only required for
              some older boards with non-programmable clocks.  Don't specify
              this entry unless the driver-specific documentation explicitly
              recommends that you do.

       ClockChip  "clockchip-type"
              This optional entry is used to specify the clock chip type on
              graphics boards which have a programmable clock generator.  Only
              a few Xorg drivers support programmable clock chips.  For
              details, see the appropriate driver manual page.

       VideoRam  mem
              This optional entry specifies the amount of video ram that is
              installed on the graphics board.  This is measured in kBytes.
              In most cases this is not required because the Xorg server
              probes the graphics board to determine this quantity.  The
              driver-specific documentation should indicate when it might be
              needed.

       MemBase  baseaddress
              This optional entry specifies the memory base address of a
              graphics board's linear frame buffer.  This entry is not used by
              many drivers, and it should only be specified if the driver-
              specific documentation recommends it.

       IOBase  baseaddress
              This optional entry specifies the IO base address.  This entry
              is not used by many drivers, and it should only be specified if
              the driver-specific documentation recommends it.

       ChipID  id
              This optional entry specifies a numerical ID representing the
              chip type.  For PCI cards, it is usually the device ID.  This
              can be used to override the auto-detection, but that should only
              be done when the driver-specific documentation recommends it.

       ChipRev  rev
              This optional entry specifies the chip revision number.  This
              can be used to override the auto-detection, but that should only
              be done when the driver-specific documentation recommends it.

       MatchSeat  seat-id
              Only apply this Device section if X server was started with
              -seat seat-id option.

       Option "ModeDebug" "boolean"
              Enable printing of additional debugging information about
              modesetting to the server log.

       Option "PreferCloneMode" "boolean"
              If enabled, bring up monitors of a screen in clone mode instead
              of horizontal extended layout by default. (Defaults to off; the
              video driver can change the default value, but this option can
              always override it)

       Options
              Option flags may be specified in the Device sections.  These
              include driver-specific options and driver-independent options.
              The former are described in the driver-specific documentation.
              Some of the latter are described below in the section about the
              Screen section, and they may also be included here.


VIDEOADAPTOR SECTION
       Nobody wants to say how this works.  Maybe nobody knows ...


MONITOR SECTION
       The config file may have multiple Monitor sections.  There should
       normally be at least one, for the monitor being used, but a default
       configuration will be created when one isn't specified.

       Monitor sections have the following format:

           Section "Monitor"
               Identifier "name"
               entries
               ...
           EndSection

       The only mandatory entry in a Monitor section is the Identifier entry.

       The Identifier entry specifies the unique name for this monitor.  The
       Monitor section may be used to provide information about the
       specifications of the monitor, monitor-specific Options, and
       information about the video modes to use with the monitor.

       With RandR 1.2-enabled drivers, monitor sections may be tied to
       specific outputs of the video card.  Using the name of the output
       defined by the video driver plus the identifier of a monitor section,
       one associates a monitor section with an output by adding an option to
       the Device section in the following format:

       Option "Monitor-outputname" "monitorsection"

       (for example, Option "Monitor-VGA" "VGA monitor" for a VGA output)

       In the absence of specific association of monitor sections to outputs,
       if a monitor section is present the server will associate it with an
       output to preserve compatibility for previous single-head
       configurations.

       Specifying video modes is optional because the server will use the DDC
       or other information provided by the monitor to automatically configure
       the list of modes available.  When modes are specified explicitly in
       the Monitor section (with the Mode, ModeLine, or UseModes keywords),
       built-in modes with the same names are not included.  Built-in modes
       with different names are, however, still implicitly included, when they
       meet the requirements of the monitor.

       The entries that may be used in Monitor sections are described below.

       VendorName  "vendor"
              This optional entry specifies the monitor's manufacturer.

       ModelName  "model"
              This optional entry specifies the monitor's model.

       HorizSync  horizsync-range
              gives the range(s) of horizontal sync frequencies supported by
              the monitor.  horizsync-range may be a comma separated list of
              either discrete values or ranges of values.  A range of values
              is two values separated by a dash.  By default the values are in
              units of kHz.  They may be specified in MHz or Hz if MHz or Hz
              is added to the end of the line.  The data given here is used by
              the Xorg server to determine if video modes are within the
              specifications of the monitor.  This information should be
              available in the monitor's handbook.  If this entry is omitted,
              a default range of 28-33kHz is used.

       VertRefresh  vertrefresh-range
              gives the range(s) of vertical refresh frequencies supported by
              the monitor.  vertrefresh-range may be a comma separated list of
              either discrete values or ranges of values.  A range of values
              is two values separated by a dash.  By default the values are in
              units of Hz.  They may be specified in MHz or kHz if MHz or kHz
              is added to the end of the line.  The data given here is used by
              the Xorg server to determine if video modes are within the
              specifications of the monitor.  This information should be
              available in the monitor's handbook.  If this entry is omitted,
              a default range of 43-72Hz is used.

       DisplaySize  width height
              This optional entry gives the width and height, in millimetres,
              of the picture area of the monitor.  If given this is used to
              calculate the horizontal and vertical pitch (DPI) of the screen.

       Gamma  gamma-value

       Gamma  red-gamma green-gamma blue-gamma
              This is an optional entry that can be used to specify the gamma
              correction for the monitor.  It may be specified as either a
              single value or as three separate RGB values.  The values should
              be in the range 0.1 to 10.0, and the default is 1.0.  Not all
              drivers are capable of using this information.

       UseModes  "modesection-id"
              Include the set of modes listed in the Modes section called
              modesection-id.  This makes all of the modes defined in that
              section available for use by this monitor.

       Mode  "name"
              This is an optional multi-line entry that can be used to provide
              definitions for video modes for the monitor.  In most cases this
              isn't necessary because the built-in set of VESA standard modes
              will be sufficient.  The Mode keyword indicates the start of a
              multi-line video mode description.  The mode description is
              terminated with the EndMode keyword.  The mode description
              consists of the following entries:

              DotClock  clock
                  is the dot (pixel) clock rate to be used for the mode.

              HTimings  hdisp hsyncstart hsyncend htotal
                  specifies the horizontal timings for the mode.

              VTimings  vdisp vsyncstart vsyncend vtotal
                  specifies the vertical timings for the mode.

              Flags  "flag" ...
                  specifies an optional set of mode flags, each of which is a
                  separate string in double quotes.  "Interlace" indicates
                  that the mode is interlaced.  "DoubleScan" indicates a mode
                  where each scanline is doubled.  "+HSync" and "-HSync" can
                  be used to select the polarity of the HSync signal.
                  "+VSync" and "-VSync" can be used to select the polarity of
                  the VSync signal.  "Composite" can be used to specify
                  composite sync on hardware where this is supported.
                  Additionally, on some hardware, "+CSync" and "-CSync" may be
                  used to select the composite sync polarity.

              HSkew  hskew
                  specifies the number of pixels (towards the right edge of
                  the screen) by which the display enable signal is to be
                  skewed.  Not all drivers use this information.  This option
                  might become necessary to override the default value
                  supplied by the server (if any).  “Roving” horizontal lines
                  indicate this value needs to be increased.  If the last few
                  pixels on a scan line appear on the left of the screen, this
                  value should be decreased.

              VScan  vscan
                  specifies the number of times each scanline is painted on
                  the screen.  Not all drivers use this information.  Values
                  less than 1 are treated as 1, which is the default.
                  Generally, the "DoubleScan" Flag mentioned above doubles
                  this value.

       ModeLine  "name" mode-description
              This entry is a more compact version of the Mode entry, and it
              also can be used to specify video modes for the monitor.  This
              is a single line format for specifying video modes.  In most
              cases this isn't necessary because the built-in set of VESA
              standard modes will be sufficient.

              The mode-description is in four sections, the first three of
              which are mandatory.  The first is the dot (pixel) clock.  This
              is a single number specifying the pixel clock rate for the mode
              in MHz.  The second section is a list of four numbers specifying
              the horizontal timings.  These numbers are the hdisp,
              hsyncstart, hsyncend, and htotal values.  The third section is a
              list of four numbers specifying the vertical timings.  These
              numbers are the vdisp, vsyncstart, vsyncend, and vtotal values.
              The final section is a list of flags specifying other
              characteristics of the mode.  Interlace indicates that the mode
              is interlaced.  DoubleScan indicates a mode where each scanline
              is doubled.  +HSync and -HSync can be used to select the
              polarity of the HSync signal.  +VSync and -VSync can be used to
              select the polarity of the VSync signal.  Composite can be used
              to specify composite sync on hardware where this is supported.
              Additionally, on some hardware, +CSync and -CSync may be used to
              select the composite sync polarity.  The HSkew and VScan options
              mentioned above in the Mode entry description can also be used
              here.

       Option "DPMS" "bool"
              This option controls whether the server should enable the DPMS
              extension for power management for this screen.  The default is
              to enable the extension.

       Option "SyncOnGreen" "bool"
              This option controls whether the video card should drive the
              sync signal on the green color pin.  Not all cards support this
              option, and most monitors do not require it.  The default is
              off.

       Option "Primary" "bool"
              This optional entry specifies that the monitor should be treated
              as the primary monitor. (RandR 1.2-supporting drivers only)

       Option "PreferredMode" "name"
              This optional entry specifies a mode to be marked as the
              preferred initial mode of the monitor.  (RandR 1.2-supporting
              drivers only)

       Option "ZoomModes" "name name ..."
              This optional entry specifies modes to be marked as zoom modes.
              It is possible to switch to the next and previous mode via
              Ctrl+Alt+Keypad-Plus and Ctrl+Alt+Keypad-Minus.  All these
              keypad available modes are selected from the screen mode list.
              This list is a copy of the compatibility output monitor mode
              list.  Since this output is the output connected to the lowest
              dot-area monitor, as determined from its largest size mode, that
              monitor defines the available zoom modes.  (RandR 1.2-supporting
              drivers only)

       Option "Position" "x y"
              This optional entry specifies the position of the monitor within
              the X screen.  (RandR 1.2-supporting drivers only)

       Option "LeftOf" "output"
              This optional entry specifies that the monitor should be
              positioned to the left of the output (not monitor) of the given
              name.  (RandR 1.2-supporting drivers only)

       Option "RightOf" "output"
              This optional entry specifies that the monitor should be
              positioned to the right of the output (not monitor) of the given
              name.  (RandR 1.2-supporting drivers only)

       Option "Above" "output"
              This optional entry specifies that the monitor should be
              positioned above the output (not monitor) of the given name.
              (RandR 1.2-supporting drivers only)

       Option "Below" "output"
              This optional entry specifies that the monitor should be
              positioned below the output (not monitor) of the given name.
              (RandR 1.2-supporting drivers only)

       Option "Enable" "bool"
              This optional entry specifies whether the monitor should be
              turned on at startup.  By default, the server will attempt to
              enable all connected monitors.  (RandR 1.2-supporting drivers
              only)

       Option "DefaultModes" "bool"
              This optional entry specifies whether the server should add
              supported default modes to the list of modes offered on this
              monitor. By default, the server will add default modes; you
              should only disable this if you can guarantee that EDID will be
              available at all times, or if you have added custom modelines
              which the server can use.  (RandR 1.2-supporting drivers only)

       Option "MinClock" "frequency"
              This optional entry specifies the minimum dot clock, in kHz,
              that is supported by the monitor.

       Option "MaxClock" "frequency"
              This optional entry specifies the maximum dot clock, in kHz,
              that is supported by the monitor.

       Option "Ignore" "bool"
              This optional entry specifies that the monitor should be ignored
              entirely, and not reported through RandR.  This is useful if the
              hardware reports the presence of outputs that don't exist.
              (RandR 1.2-supporting drivers only)

       Option "Rotate" "rotation"
              This optional entry specifies the initial rotation of the given
              monitor.  Valid values for rotation are "normal", "left",
              "right", and "inverted".  (RandR 1.2-supporting drivers only)


MODES SECTION
       The config file may have multiple Modes sections, or none.  These
       sections provide a way of defining sets of video modes independently of
       the Monitor sections.  Monitor sections may include the definitions
       provided in these sections by using the UseModes keyword.  In most
       cases the Modes sections are not necessary because the built-in set of
       VESA standard modes will be sufficient.

       Modes sections have the following format:

           Section "Modes"
               Identifier "name"
               entries
               ...
           EndSection

       The Identifier entry specifies the unique name for this set of mode
       descriptions.  The other entries permitted in Modes sections are the
       Mode and ModeLine entries that are described above in the Monitor
       section.

SCREEN SECTION
       The config file may have multiple Screen sections.  There must be at
       least one, for the “screen” being used.  A “screen” represents the
       binding of a graphics device (Device section) and a monitor (Monitor
       section).  A Screen section is considered “active” if it is referenced
       by an active ServerLayout section or by the -screen command line
       option.  If neither of those is present, the first Screen section found
       in the config file is considered the active one.

       Screen sections have the following format:

           Section "Screen"
               Identifier "name"
               Device     "devid"
               GPUDevice  "devid"
               Monitor    "monid"
               entries
               ...
               SubSection "Display"
                  entries
                  ...
               EndSubSection
               ...
           EndSection

       The Identifier entry is mandatory.  All others are optional.

       The Identifier entry specifies the unique name for this screen.  The
       Screen section provides information specific to the whole screen,
       including screen-specific Options.  In multi-head configurations, there
       will be multiple active Screen sections, one for each head.  The
       entries available for this section are:

       Device  "device-id"
              This entry specifies the Device section to be used for this
              screen.  When multiple graphics cards are present, this is what
              ties a specific card to a screen.  The device-id must match the
              Identifier of a Device section in the config file.

       GPUDevice  "device-id"
              This entry specifies the Device section to be used as a
              secondary GPU device for this screen.  When multiple graphics
              cards are present, this is what ties a specific secondary card
              to a screen.  The device-id must match the Identifier of a
              Device section in the config file. This can be specified up to 4
              times for a single screen.

       Monitor  "monitor-id"
              specifies which monitor description is to be used for this
              screen.  If a Monitor name is not specified, a default
              configuration is used.  Currently the default configuration may
              not function as expected on all platforms.

       VideoAdaptor  "xv-id"
              specifies an optional Xv video adaptor description to be used
              with this screen.

       DefaultDepth  depth
              specifies which color depth the server should use by default.
              The -depth command line option can be used to override this.  If
              neither is specified, the default depth is driver-specific, but
              in most cases is 8.

       DefaultFbBpp  bpp
              specifies which framebuffer layout to use by default.  The
              -fbbpp command line option can be used to override this.  In
              most cases the driver will chose the best default value for
              this.  The only case where there is even a choice in this value
              is for depth 24, where some hardware supports both a packed 24
              bit framebuffer layout and a sparse 32 bit framebuffer layout.

       MatchSeat  seat-id
              Only apply this Screen section if X server was started with
              -seat seat-id option.

       Options
              Various Option flags may be specified in the Screen section.
              Some are driver-specific and are described in the driver
              documentation.  Others are driver-independent, and will
              eventually be described here.

       Option "Accel"
              Enables 2D hardware acceleration.  This option is on by default,
              but it may be necessary to turn it off if there are bugs in the
              driver.  There are many options to disable specific accelerated
              operations, listed below.  Note that disabling an operation will
              have no effect if the operation is not accelerated (whether due
              to lack of support in the hardware or in the driver).

       Option "GlxVendorLibrary" "string"
              This option specifies a space-separated list of OpenGL vendor
              libraries to use for the screen. This may be used to select an
              alternate implementation for development, debugging, or
              alternate feature sets.  Default: mesa.

       Option "InitPrimary" "boolean"
              Use the Int10 module to initialize the primary graphics card.
              Normally, only secondary cards are soft-booted using the Int10
              module, as the primary card has already been initialized by the
              BIOS at boot time.  Default: false.

       Option "NoInt10" "boolean"
              Disables the Int10 module, a module that uses the int10 call to
              the BIOS of the graphics card to initialize it.  Default: false.

       Each Screen section may optionally contain one or more Display
       subsections.  Those subsections provide depth/fbbpp specific
       configuration information, and the one chosen depends on the depth
       and/or fbbpp that is being used for the screen.  The Display subsection
       format is described in the section below.


DISPLAY SUBSECTION
       Each Screen section may have multiple Display subsections.  The
       “active” Display subsection is the first that matches the depth and/or
       fbbpp values being used, or failing that, the first that has neither a
       depth or fbbpp value specified.  The Display subsections are optional.
       When there isn't one that matches the depth and/or fbbpp values being
       used, all the parameters that can be specified here fall back to their
       defaults.

       Display subsections have the following format:

               SubSection "Display"
                   Depth  depth
                   entries
                   ...
               EndSubSection

       Depth  depth
              This entry specifies what colour depth the Display subsection is
              to be used for.  This entry is usually specified, but it may be
              omitted to create a match-all Display subsection or when wishing
              to match only against the FbBpp parameter.  The range of depth
              values that are allowed depends on the driver.  Most drivers
              support 8, 15, 16 and 24.  Some also support 1 and/or 4, and
              some may support other values (like 30).  Note: depth means the
              number of bits in a pixel that are actually used to determine
              the pixel colour.  32 is not a valid depth value.  Most hardware
              that uses 32 bits per pixel only uses 24 of them to hold the
              colour information, which means that the colour depth is 24, not
              32.

       FbBpp  bpp
              This entry specifies the framebuffer format this Display
              subsection is to be used for.  This entry is only needed when
              providing depth 24 configurations that allow a choice between a
              24 bpp packed framebuffer format and a 32bpp sparse framebuffer
              format.  In most cases this entry should not be used.

       Weight  red-weight green-weight blue-weight
              This optional entry specifies the relative RGB weighting to be
              used for a screen is being used at depth 16 for drivers that
              allow multiple formats.  This may also be specified from the
              command line with the -weight option (see Xorg(1)).

       Virtual  xdim ydim
              This optional entry specifies the virtual screen resolution to
              be used.  xdim must be a multiple of either 8 or 16 for most
              drivers, and a multiple of 32 when running in monochrome mode.
              The given value will be rounded down if this is not the case.
              Video modes which are too large for the specified virtual size
              will be rejected.  If this entry is not present, the virtual
              screen resolution will be set to accommodate all the valid video
              modes given in the Modes entry.  Some drivers/hardware
              combinations do not support virtual screens.  Refer to the
              appropriate driver-specific documentation for details.

       ViewPort  x0 y0
              This optional entry sets the upper left corner of the initial
              display.  This is only relevant when the virtual screen
              resolution is different from the resolution of the initial video
              mode.  If this entry is not given, then the initial display will
              be centered in the virtual display area.

       Modes  "mode-name" ...
              This optional entry specifies the list of video modes to use.
              Each mode-name specified must be in double quotes.  They must
              correspond to those specified or referenced in the appropriate
              Monitor section (including implicitly referenced built-in VESA
              standard modes).  The server will delete modes from this list
              which don't satisfy various requirements.  The first valid mode
              in this list will be the default display mode for startup.  The
              list of valid modes is converted internally into a circular
              list.  It is possible to switch to the next mode with
              Ctrl+Alt+Keypad-Plus and to the previous mode with
              Ctrl+Alt+Keypad-Minus.  When this entry is omitted, the valid
              modes referenced by the appropriate Monitor section will be
              used.  If the Monitor section contains no modes, then the
              selection will be taken from the built-in VESA standard modes.

       Visual  "visual-name"
              This optional entry sets the default root visual type.  This may
              also be specified from the command line (see the Xserver(1) man
              page).  The visual types available for depth 8 are (default is
              PseudoColor):

                  StaticGray
                  GrayScale
                  StaticColor
                  PseudoColor
                  TrueColor
                  DirectColor

              The visual type available for the depths 15, 16 and 24 are
              (default is TrueColor):

                  TrueColor
                  DirectColor

              Not all drivers support DirectColor at these depths.

              The visual types available for the depth 4 are (default is
              StaticColor):

                  StaticGray
                  GrayScale
                  StaticColor
                  PseudoColor

              The visual type available for the depth 1 (monochrome) is
              StaticGray.

       Black  red green blue
              This optional entry allows the “black” colour to be specified.
              This is only supported at depth 1.  The default is black.

       White  red green blue
              This optional entry allows the “white” colour to be specified.
              This is only supported at depth 1.  The default is white.

       Options
              Option flags may be specified in the Display subsections.  These
              may include driver-specific options and driver-independent
              options.  The former are described in the driver-specific
              documentation.  Some of the latter are described above in the
              section about the Screen section, and they may also be included
              here.

SERVERLAYOUT SECTION
       The config file may have multiple ServerLayout sections.  A “server
       layout” represents the binding of one or more screens (Screen sections)
       and one or more input devices (InputDevice sections) to form a complete
       configuration.  In multi-head configurations, it also specifies the
       relative layout of the heads.  A ServerLayout section is considered
       “active” if it is referenced by the -layout command line option or by
       an Option "DefaultServerLayout" entry in the ServerFlags section (the
       former takes precedence over the latter).  If those options are not
       used, the first ServerLayout section found in the config file is
       considered the active one.  If no ServerLayout sections are present,
       the single active screen and two active (core) input devices are
       selected as described in the relevant sections above.

       ServerLayout sections have the following format:

           Section "ServerLayout"
               Identifier   "name"
               Screen       "screen-id"
               ...
               InputDevice  "idev-id"
               ...
               options
               ...
           EndSection

       Each ServerLayout section must have an Identifier entry and at least
       one Screen entry.

       The Identifier entry specifies the unique name for this server layout.
       The ServerLayout section provides information specific to the whole
       session, including session-specific Options.  The ServerFlags options
       (described above) may be specified here, and ones given here override
       those given in the ServerFlags section.

       The entries that may be used in this section are described here.

       Screen  screen-num "screen-id" position-information
              One of these entries must be given for each screen being used in
              a session.  The screen-id field is mandatory, and specifies the
              Screen section being referenced.  The screen-num field is
              optional, and may be used to specify the screen number in
              multi-head configurations.  When this field is omitted, the
              screens will be numbered in the order that they are listed in.
              The numbering starts from 0, and must be consecutive.  The
              position-information field describes the way multiple screens
              are positioned.  There are a number of different ways that this
              information can be provided:

              x y

              Absolute  x y
                  These both specify that the upper left corner's coordinates
                  are (x,y).  The Absolute keyword is optional.  Some older
                  versions of XFree86 (4.2 and earlier) don't recognise the
                  Absolute keyword, so it's safest to just specify the
                  coordinates without it.

              RightOf   "screen-id"

              LeftOf    "screen-id"

              Above     "screen-id"

              Below     "screen-id"

              Relative  "screen-id" x y
                  These give the screen's location relative to another screen.
                  The first four position the screen immediately to the right,
                  left, above or below the other screen.  When positioning to
                  the right or left, the top edges are aligned.  When
                  positioning above or below, the left edges are aligned.  The
                  Relative form specifies the offset of the screen's origin
                  (upper left corner) relative to the origin of another
                  screen.

       InputDevice  "idev-id" "option" ...
              One of these entries should be given for each input device being
              used in a session.  Normally at least two are required, one each
              for the core pointer and keyboard devices.  If either of those
              is missing, suitable InputDevice entries are searched for using
              the method described above in the INPUTDEVICE section.  The
              idev-id field is mandatory, and specifies the name of the
              InputDevice section being referenced.  Multiple option fields
              may be specified, each in double quotes.  The options permitted
              here are any that may also be given in the InputDevice sections.
              Normally only session-specific input device options would be
              used here.  The most commonly used options are:

                  "CorePointer"
                  "CoreKeyboard"
                  "SendCoreEvents"

              and the first two should normally be used to indicate the core
              pointer and core keyboard devices respectively.

       MatchSeat  seat-id
              Only apply this ServerLayout section if X server was started
              with -seat seat-id option.

       Options
              In addition to the following, any option permitted in the
              ServerFlags section may also be specified here.  When the same
              option appears in both places, the value given here overrides
              the one given in the ServerFlags section.

       Option "IsolateDevice"  "bus-id"
              Restrict device resets to the specified bus-id.  See the BusID
              option (described in DEVICE SECTION, above) for the format of
              the bus-id parameter.  This option overrides SingleCard, if
              specified.  At present, only PCI devices can be isolated in this
              manner.

       Option "SingleCard"  "boolean"
              As IsolateDevice, except that the bus ID of the first device in
              the layout is used.

       Here is an example of a ServerLayout section for a dual headed
       configuration with two mice:

           Section "ServerLayout"
               Identifier  "Layout 1"
               Screen      "MGA 1"
               Screen      "MGA 2" RightOf "MGA 1"
               InputDevice "Keyboard 1" "CoreKeyboard"
               InputDevice "Mouse 1"    "CorePointer"
               InputDevice "Mouse 2"    "SendCoreEvents"
               Option      "BlankTime"  "5"
           EndSection

DRI SECTION
       This optional section is used to provide some information for the
       Direct Rendering Infrastructure.  Details about the format of this
       section can be found on-line at <https://dri.freedesktop.org/>.

VENDOR SECTION
       The optional Vendor section may be used to provide vendor-specific
       configuration information.  Multiple Vendor sections may be present,
       and they may contain an Identifier entry and multiple Option flags.
       The data therein is not used in this release.

SEE ALSO
       General: X(7), Xserver(1), Xorg(1), cvt(1), gtf(1).

       Not all modules or interfaces are available on all platforms.

       Display drivers: apm(4), ati(4), chips(4), cirrus(4), cyrix(4),
       fbdev(4), glide(4), glint(4), i128(4), i740(4), imstt(4), intel(4),
       mga(4), neomagic(4), nv(4), openchrome(4), r128(4), radeon(4),
       rendition(4), savage(4), s3virge(4), siliconmotion(4), sis(4),
       sisusb(4), sunbw2(4), suncg14(4), suncg3(4), suncg6(4), sunffb(4),
       sunleo(4), suntcx(4), tdfx(4), trident(4), tseng(4), vesa(4),
       vmware(4), voodoo(4), wsfb(4), xgi(4), xgixp(4).

       Input drivers: acecad(4), citron(4), elographics(4), evdev(4), fpit(4),
       joystick(4), kbd(4), libinput(4), mousedrv(4), mutouch(4), penmount(4),
       synaptics(4), vmmouse(4), void(4), wacom(4).

       Other modules and interfaces: exa(4), fbdevhw(4), v4l(4).

AUTHORS
       This manual page was largely rewritten by David Dawes
       <dawes@xfree86.org>.



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