X Server Configuration

Device-independent server options, and

For each screen:

[ServerOptions

{Screen 〈device_name〉} ||

{SingleLogicalScreen 〈nRows〉 〈nCols〉 〈device_name1〉...〈device_nameN〉}

[DefaultVisual

[MonitorSize 〈diagonal_length〉 〈units〉]

[MinimumMonitorPowerSaveLevel 〈level〉]

[ScreenOptions

This is the minimum legal X*screens file, the "Screen" keyword followed by the screen device. Since no other information is given, the X server will assume default values for other options and settings.

Screen /dev/crt

Figure 5-1 Results of Minimal Legal X*screens File

This is the minimum specification for a two-screen configuration. The maximum number of screens supported on the X server is four. Here, the displays associated with /dev/crt0 and /dev/crt1 are referred to as "〈host〉:0.0" and "〈host〉:0.1", respectively.

Screen /dev/crt0
Screen /dev/crt1

Figure 5-2 Two Physical Displays, Two Separate Screens

This sample X*screens file could be used on a system using Internal Color Graphics with a 17-inch monitor. In this example, the GraphicsSharedMemorySize is decreased to 1 Mbyte in order to reduce the swap space requirements of the system. Decreasing GraphicsSharedMemorySize is appropriate when you do not intend to run any 3D graphics applications.

ServerOptions
    GraphicsSharedMemorySize 0x100000
Screen /dev/crt
    MonitorSize 17 inches

The display diagram would be the same as that of the "Results of Minimal Legal X*screens File" configuration, above.

This sample X*screens file could be used on a system with a CRX24 graphics device. The overlay visual is selected as the default. There are 255 overlay colormap entries available on the CRX24. The 256th entry is hard-wired to transparent. Having less than 256 colormap entries should not cause a problem for most applications, but for those applications that require 256 colormap entries, the CountTransparentInOverlayVisual screen option should be used as shown below. Note that any attempts to modify the 256th entry will have no effect on the colormap.

Screen /dev/crt
    ScreenOptions
        CountTransparentInOverlayVisual

The display diagram would be the same as that of the "Results of Minimal Legal X*screens File" configuration, above.

This sample X*screens file could be used on a system with a HCRX-24 graphics device. The default visual on the HCRX-24 is the opaque overlay visual. All 256 colormap entries are opaque and allocable. If an application requires transparency in the default visual, the "Transparent" keyword can be used to select the transparent overlay visual as shown below.

Screen /dev/crt
    DefaultVisual
        Transparent

The display diagram would be the same as that of the "Results of Minimal Legal X*screens File" configuration, above.

This sample X*screens file could be used on a system with a HCRX-8 graphics device. By default on the HCRX-8, the overlay visual does not have a transparent entry available to applications for rendering transparency. If an application requires overlay transparency, an optional X server mode is available, but it is restrictive. In this optional mode, only one hardware colormap is available in the overlays (instead of two) and only one hardware colormap is available in the image planes (instead of two). The optional X server mode can be set via the EnableOverlayTransparency screen option as shown below.

Screen /dev/crt
    ScreenOptions
        EnableOverlayTransparency

The display diagram would be the same as that of the "Results of Minimal Legal X*screens File" configuration, above.

This sample X*screens file could be used on a system using either a PVRX or TVRX graphics device. The server will run in combined mode with the default visual residing in the overlay planes. All visual depths which are supported by the graphics device will be available.

Screen /dev/ocrt
    ScreenOptions
        VRXSecondaryDevice /dev/crt

Figure 5-3 PVRX/TVRX Display with Overlays

This sample X*screens file could also be used on a system using PVRX or TVRX graphics. The server will run in combined mode with the default visual in the overlay planes and an 8/8 double-buffered visual in the image planes. In general, specify VRXDoubleBuffer if applications will be using DHA (Direct Hardware Access) double-buffer functionality (e.g., Starbase double buffering).

Screen /dev/ocrt
    ScreenOptions
        VRXSecondaryDevice  /dev/crt
        VRXDepth            16
        VRXDoubleBuffer

The display diagram would be the same as that of the "PVRX/TVRX Display with Overlays" configuration, above.

These sample X*screens file entries could be used on a system with two homogeneous graphics devices. Assuming the first device is associated with the device file "/dev/crt0" and the second device is associated with the device file "/dev/crt1", both examples specify a horizontal Single Logical Screen configuration.

SingleLogicalScreen 1 2
    /dev/crt0 /dev/crt1
        or
SingleLogicalScreen 1 2
    /dev/crt0
    /dev/crt1

Figure 5-4 Two Physical Displays, Single Logical Screen (1×2)

These sample X*screens entries could be used on a system with four homogeneous graphics devices. Assuming the first device is associated with the device file "/dev/crt0", the second device is associated with the device file "/dev/crt1", etc. The following examples specify valid Single Logical Screen configurations.

It is possible to include a Screen Entry and an SLS Screen Entry in the same X*screens File. This creates a situation where there are two X Screens (e.g. 〈host〉:0.0 and 〈host〉:1.0), one of which happens to be a Single Logical Screen. Below is an example of this:

Screen /dev/crt0
SingleLogicalScreen 1 2
    /dev/crt1 /dev/crt2

Figure 5-8 Three Physical Displays, Screen plus Single Logical Screen (1×2)