Graphics Administration Guide (July 2008)

Display subsection
The Screen sections include one or more Display subsections. One Display subsection
may be provided for each depth that the server supports. The size of the Xserver’s
virtual screen may also be specified. The virtual screen allows you to have a “root
window” larger than what can be displayed on the monitor. (e.g. the monitor may be
a 800x600 display, but have a 1280x1024 virtual size). The Virtual keyword is used to
specify this size. Note that many of the new accelerated graphics drivers use
non-displayed memory for caching. It is not desirable to use all available memory for
the virtual display, as this leaves none for caching, and this can decrease server
performance. Display subsections have the following format:
SubSection "Display"
Depth <depth>
Visual <visual>
Modes "ModeName"
ViewPort <x0> <y0>
Option ...
...
EndSubSection
The Depth entry specifies what color depth the Display subsection is to be used for.
Only depths of 8 and 24 are supported.
The Modes entry specifies the list of video modes to use. Each ModeName specified
must be in double quotes. They must correspond to those specified or referenced in
the appropriate Monitor section. The server will delete modes from this list which don't
satisfy various requirements. The first valid mode in this list will be the default display
mode for startup. The list of valid modes is converted internally into a circular list. It
is possible to switch to the next mode with Ctrl+Alt+Keypad-Plus and to the previous
mode with Ctrl+Alt+Keypad-Minus. When this entry is omitted, the largest valid mode
referenced by the appropriate Monitor section will be used.
The Visual entry is optional and sets the default root visual type.
The visual type available for the depth 8 is: PseudoColor
The visual type available for depth 24 is: TrueColor
The ViewPort optional entry sets the upper left corner of the initial display. This is only
relevant when the virtual screen resolution is different from the resolution of the initial
video mode. If this entry is not given, then the initial display will be centered in the
virtual display area. Source: XF86Config man page.
Option flags may be specified in the Display subsections. These may include
driver-specific options or driver-independent options. The former are described in the
driver-specific documentation. Some of the latter are described above in the section
about the Screen section, and they may also be included here. However, options set in
the Display subsection may be “overridden” in the Screen section.
the XF86Config file 21