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:
Section "InputDevice" Identifier "Keyboard0" Driver "kbd" Option "XkbModel" "pc105" Option "XkbLayout" "us" EndSection
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.
Option — Specifies necessary options pertaining to 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.conf:
Protocol — Specifies the protocol used by the mouse, such as IMPS/2.
Device — Specifies the location of the physical device.
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.conf man page for a list of valid options for this section.