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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 mecha-
       nisms 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 param-
       eters, with their defaults, are described below. Driver and module spe-
       cific  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 op-
       tion (which may be absolute or relative), $XORGCONFIG is the path spec-
       ified by that environment variable (absolute or relative), $HOME is the
       path specified by that environment variable (usually  the  home  direc-
       tory), and <hostname> is the machine's hostname as reported by gethost-
       name(3).

       Additional configuration files are searched for in the following direc-
       tories 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  direc-
       tory 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 sec-
       tions which may be present in any order, or omitted to use default con-
       figuration 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 compati-
       bility 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 usu-
       ally 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  ServerLay-
       out 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 ig-
       nored.  Most strings (including Option names)  are  also  case-insensi-
       tive, 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 op-
       tional 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 cat-
                  alogue: before the directory name. The directory can then be
                  populated  with  symlinks pointing to the real font directo-
                  ries, using the following syntax in the symlink name:

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

                  where <identifier> is an  alphanumeric  identifier,  [attri-
                  bute] 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 ma-
                  chine 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 cat-
              alogue 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 speci-
              fied.  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

                  /usr/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  compati-
       bility  purposes  some  of  the old style entries are still recognised.
       Those old style entries are not documented here, and using them is dis-
       couraged.  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  "Default-
       ServerLayout" Option) may be overridden by Options specified in the ac-
       tive 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  de-
              bugging  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 "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 operat-
              ing  systems  that  have  this feature.  When this option is en-
              abled, 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 (usu-
              ally on Ctrl+Alt+Backspace, depending on XKB options).  This ac-
              tion  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.  De-
              fault: 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 screen-
              saver.  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  visu-
              als.   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  dis-
              abled 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".  En-
              abled 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  au-
       tomatically when they are needed via other mechanisms.  The Module sec-
       tion 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 com-
       monly 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 follow-
              ing entry:

                  Load "dri"

       Disable  "modulename"
              This instructs the server to not load the module called  module-
              name.   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 in-
              struction, the standard name is case-sensitive, and does not in-
              clude the "lib" prefix, or the ".a", ".o", or ".so" suffixes.

       The  second form of entry is a SubSection, with the subsection name be-
       ing 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  dis-
       abled 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  mul-
       timedia  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 sub-
       directory under:

           /usr/lib/xorg/modules

       The “extmod”, “dbe”, “dri”, “dri2”, “glx”, and “record” extension  mod-
       ules  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 sec-
       ond.  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 follow-
              ing 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  ei-
       ther  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 sec-
       tions.  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  "in-
       putdriver"  will be loaded for each active InputDevice section.  An In-
       putDevice 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 Core-
              Pointer, CoreKeyboard, AlwaysCore, and SendCoreEvents,  are  the
              inverse of option Floating (i.e.  SendCoreEvents "on" is equiva-
              lent 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 de-
              vices. 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 repre-
              sent 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 de-
       tails. 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 cur-
              rent  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 thresh-
              old, can be used to tweak profiles to suit the users needs.  The
              simple  and limited profiles use it directly (i.e. they acceler-
              ate 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 op-
       tional entries to narrow the match of the class. If  none  of  the  op-
       tional 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 de-
       vice.  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  sup-
              ported 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 cur-
              rently configured driver of the device. Ordering of sections us-
              ing  this  entry is important since it will not match unless the
              driver has been set by the config backend or a  previous  Input-
              Class 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  cur-
              rently  active ServerLayout section. The empty string "" matches
              an implicit layout which appears if no named  ServerLayout  sec-
              tions have been found.

       The  above  directives  have equivalents for negative matching with the
       NoMatchProduct, NoMatchVendor, NoMatchDevicePath, NoMatchOS, NoMatchPn-
       PID,  NoMatchUSBID, NoMatchDriver, NoMatchTag, and NoMatchLayout direc-
       tives. 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 Op-
       tion 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 out-
       put devices as they are automatically  added.   An  output  device  can
       match  more than one OutputClass section.  Each class can override set-
       tings 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 out-
       put device.  After all classes have been examined,  the  "outputdriver"
       module from the first Driver entry will be enabled when using the load-
       able server.

       When an output device is automatically added, its  characteristics  are
       checked against all OutputClass sections.  Each section can contain op-
       tional entries to narrow the match of the class.  If none  of  the  op-
       tional  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 Op-
       tion 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 Out-
              putClass 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  de-
       vice.   The  Driver  entry  specifies the name of the driver to use for
       this graphics device.  When using the loadable server, the driver  mod-
       ule  "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-in-
       dependent  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:de-
              vice: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 configura-
              tions, 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 sin-
              gle 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  be-
              cause  the  drivers  will  probe  the  hardware to determine the
              chipset type.  Don't specify it unless the driver-specific docu-
              mentation 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 rat-
              ing of the RAMDAC is different from the  defaults  built  in  to
              driver,  or  when  the  driver can't auto-detect the correct de-
              faults.  Don't specify it unless the driver-specific  documenta-
              tion 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  de-
              tails, 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-spe-
              cific 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 mode-
              setting to the server log.

       Option "NoOutputInitialSize" "width height"
              Normally, the X server infers the initial screen size  based  on
              any  connected  outputs.   However, if no outputs are connected,
              the X server picks a default screen size of 1024  x  768.   This
              option  overrides the default screen size to use when no outputs
              are connected.  In contrast to the "Virtual" Display  SubSection
              entry,  which  applies unconditionally, "NoOutputInitialSize" is
              only used if no outputs are detected when the X server starts.

       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 in-
              clude 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 nor-
       mally be at least one, for the monitor being used, but a  default  con-
       figuration 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 specifica-
       tions  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  spe-
       cific  outputs of the video card.  Using the name of the output defined
       by the video driver plus the identifier of a monitor section, one asso-
       ciates  a monitor section with an output by adding an option to the De-
       vice 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  configura-
       tions.

       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 spec-
              ifications 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 spec-
              ifications 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 mod-
              esection-id.  This makes all of the modes defined in  that  sec-
              tion 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 ter-
              minated 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 com-
                  posite sync on hardware where this is supported.   Addition-
                  ally, 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 sup-
                  plied by the server (if any).  “Roving” horizontal lines in-
                  dicate  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.  Gener-
                  ally, 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, hsync-
              start, 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 fi-
              nal  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 po-
              larity of the VSync signal.  Composite can be  used  to  specify
              composite  sync  on hardware where this is supported.  Addition-
              ally, on some hardware, +CSync and -CSync may be used to  select
              the  composite  sync polarity.  The HSkew and VScan options men-
              tioned 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 pre-
              ferred initial mode of the monitor.  (RandR 1.2-supporting driv-
              ers 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 key-
              pad 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  posi-
              tioned  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  posi-
              tioned  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  posi-
              tioned 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  posi-
              tioned 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 sup-
              ported default modes to the list of modes offered on this  moni-
              tor.  By  default, the server will add default modes; you should
              only disable this if you can guarantee that EDID will be  avail-
              able  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 sec-
       tions 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 de-
       scriptions.  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  op-
       tion.   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, in-
       cluding screen-specific Options.  In multi-head  configurations,  there
       will  be  multiple  active Screen sections, one for each head.  The en-
       tries 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 sec-
              ondary 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 configu-
              ration 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  docu-
              mentation.   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 alter-
              nate 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  subsec-
       tions.   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 de-
       scribed in the section below.

DISPLAY SUBSECTION
       Each Screen section may have multiple Display  subsections.   The  “ac-
       tive”  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 subsec-
              tion is to be used for.  This entry is only needed when  provid-
              ing 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 al-
              low  multiple formats.  This may also be specified from the com-
              mand 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 combina-
              tions 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  resolu-
              tion 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+Key-
              pad-Minus.   When  this entry is omitted, the valid modes refer-
              enced 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 (de-
              fault is TrueColor):

                  TrueColor
                  DirectColor

              Not all drivers support DirectColor at these depths.

              The visual types available for the depth 4 are (default is Stat-
              icColor):

                  StaticGray
                  GrayScale
                  StaticColor
                  PseudoColor

              The  visual type available for the depth 1 (monochrome) is Stat-
              icGray.

       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 op-
              tions.  The former are described in the driver-specific documen-
              tation.   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  con-
       sidered  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  op-
              tional,  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 posi-
              tion-information  field  describes  the way multiple screens are
              positioned.  There are a number of different ways that this  in-
              formation 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 coordi-
                  nates 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  posi-
                  tioning  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 Input-
              Device 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 configu-
       ration 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 Di-
       rect Rendering Infrastructure.  Details about the format of  this  sec-
       tion can be found on-line at <https://dri.freedesktop.org/>.

VENDOR SECTION
       The optional Vendor section may be used to provide vendor-specific con-
       figuration 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),  fb-
       dev(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),  rendi-
       tion(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>.

X Version 11                  xorg-server 21.1.7                  xorg.conf(5)

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