Where to find xorg.conf

ModulePath — An optional parameter which specifies alternate directories which store X server modules. The default directory for loading these modules can be changed by specifying a different directory with the optional ModulePath parameter in the Files section. Each InputDevice section configures one input device for the X server. Systems typically have at least one InputDevice section for the keyboard.

It is perfectly normal to have no entry for a mouse, as most mouse settings are automatically detected. The following example illustrates a typical InputDevice section for a keyboard:. The following entries are commonly used in the InputDevice section:. Identifier — Specifies a unique name for this InputDevice section. This is a required entry. Driver — Specifies the name of the device driver X must load for the device.

A mouse may also be specified to override any autodetected defaults for the device. The following options are typically included when adding a mouse in the xorg. Emulate3Buttons — Specifies whether to allow a two-button mouse to act like a three-button mouse when both mouse buttons are pressed simultaneously.

Consult the xorg. Each Monitor section configures one type of monitor used by the system. This is an optional entry as well, as most monitors are now automatically detected. The easiest way to configure a monitor is to configure X during the installation process or by using the X Configuration Tool.

Inappropriate values can damage or destroy a monitor. Consult the monitor's documentation for a listing of safe operating parameters. Identifier — Specifies a unique name for this Monitor section. VendorName — An optional parameter which specifies the vendor of the monitor. ModelName — An optional parameter which specifies the monitor's model name. DisplaySize — An optional parameter which specifies, in millimeters, the physical size of the monitor's picture area.

HorizSync — Specifies the range of horizontal sync frequencies compatible with the monitor in kHz. These values help the X server determine the validity of built-in or specified Modeline entries for the monitor. 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. The Identifier entry specifies the unique name for this input class. 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.

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. 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.

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. 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.

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.

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. If none of the optional entries appear, the OutputClass section is generic and will match any output device. The following list of tokens can be matched against attributes of the device. 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. 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. 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 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. 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.

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. 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. 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. Clocks clock 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. 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. Maybe nobody knows 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. 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. You can also generate a skeleton for xorg. This should create a xorg.

For input devices the X server defaults to the libinput driver xfinput-libinput , but xfinput-evdev and related drivers are available as alternative. Udev , which is provided as a systemd dependency, will detect hardware and both drivers will act as hotplugging input driver for almost all devices, as defined in the default configuration files quirks.

After starting X server, the log file will show which driver hotplugged for the individual devices note the most recent log file name may vary :. If both do not support a particular device, install the needed driver from the xorg-drivers group.

The same applies, if you want to use another driver. For specific instructions, see also the libinput article, the following pages below, or Fedora:Input device configuration for more examples. See Keyboard input Identifying keycodes in Xorg. See libinput or Synaptics. See Keyboard configuration in Xorg. For a headless configuration, the xfvideo-dummy driver is necessary; install it and create a configuration file, such as the following:. See main article Multihead for general information.

You must define the correct driver to use and put the bus ID of your graphic cards in decimal notation. The factual accuracy of this article or section is disputed. In order to get correct dots per inch DPI set, the display size must be recognized or set. Having the correct DPI is especially necessary where fine detail is required like font rendering.

Previously, manufacturers tried to create a standard for 96 DPI a These days, screen DPIs vary and may not be equal horizontally and vertically. To be able to set the DPI, the Xorg server attempts to auto-detect your monitor's physical screen size through the graphic card with DDC. When the Xorg server knows the physical screen size, it will be able to set the correct DPI depending on resolution size.

Check that the dimensions match your display size. If the Xorg server is not able to correctly calculate the screen size, it will default to 75x75 DPI and you will have to calculate it yourself. If you have specifications on the physical size of the screen, they can be entered in the Xorg configuration file so that the proper DPI is calculated adjust identifier to your xrandr output :.

If you only want to enter the specification of your monitor without creating a full xorg. If you do not have specifications for physical screen width and height most specifications these days only list by diagonal size , you can use the monitor's native resolution or aspect ratio and diagonal length to calculate the horizontal and vertical physical dimensions.

Using the Pythagorean theorem on a This will give the pixel diagonal length and with this value you can discover the physical horizontal and vertical lengths and convert them to millimeters :.

To make it permanent, see Autostarting On Xorg startup. To find out whether this is happening to you, check with:. With GTK library versions since 3. Note Manually creating xorg. It is typically desirable to run the X server without any special configuration.

If you still can't get a working configuration, then read on. Section "Monitor" Identifier "My Monitor" Category : X. Enables or disables the automatic detection of input devices using udev. Specify the input device driver, see the input device articles.