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CGTHREE(4) Device Drivers Manual (sparc) CGTHREE(4)

cgthree8-bit color frame buffer

cgthree* at sbus?
cgthree* at obio0 (some sun4m models)
wsdisplay* at cgthree?

The cgthree is a color frame buffer, available as an SBus card or on-board on some sun4c and sun4m workstations. A small number of frame buffer SBus cards, not manufactured by Sun, are cgthree-compatible and will also be recognized by the cgthree driver.

The cgthree driver interfaces the frame buffer with the wscons(4) console framework. It does not provide direct device driver entry points but makes its functions available via the internal wsdisplay(4) interface.

If the cgthree frame buffer is used as the console display, it is possible, for some models, to select a different resolution than the default 1152x900 or 1024x768 by changing the OpenPROM environment. To change the default resolution, type the following:

  ok setenv screen:r1152x900x66

to change to a 66Hz 1152x900 resolution.

If the cgthree frame buffer is a secondary display, or a serial console is used, the display resolution cannot be changed without using an OpenPROM script. Refer to the for details.

The cgthree frame buffer accepts the following resolutions:

Super VGA 1024x768, with a refresh rate of 77Hz. This is the default setting on model 501-2691.
Standard 1152x900, with a refresh rate of 66Hz. This is the default setting on older models (501-1415 and 501-8044).
Standard 1152x900, with a refresh rate of 76Hz. This is the default setting on more recent models (501-1718 and 501-1909).

Note that not all models support settings other than their default setting.

These frame buffers are cgthree-compatible cards with a VGA-compatible video connector. There are only two resolutions supported, selected by jumper JP2 on the card:

1024x768, 60Hz
1152x900, 66Hz

intro(4), sbus(4), wscons(4), wsdisplay(4)

Sun Frame Buffer FAQ,

November 1, 2015 OpenBSD-5.9