NAME

vga − VGA controller device

SYNOPSIS

­bind #v /dev
 ­/dev/vgactl

DESCRIPTION

The VGA device allows configuration of a graphics controller on a PC.  ­Vgactl allows control over higher-level settings such as display height, width, depth, controller and hardware-cursor type.  Along with the I/O-port registers provided by arch(3), it is used to implement configuration and setup of VGA controller cards. This is usually performed by vga(8).

Writing strings to ­vgactl configures the VGA device.  The following are valid commands. 

size XxYxZ chan
Set the size of the screen image to be ­X pixels wide and ­Y pixels high.  Each pixel is ­Z bits as specified by chan, whose format is described in image(6).

actualsize XxY
Set the physical size of the display to be ­X pixels wide by ­Y pixels high.  This message is optional; if this size is smaller than that specified in the ­size message, the screen will pan to follow the mouse.  This is useful on systems with small displays, such as laptops. 

type ctlr
Set the type of VGA controller being used. ­Ctlr is one of ark200pv, clgd542x, clgd546x, ct65545, cyber938x, hiqvideo, mach64xx, mga2164w, neomagic, s3, and t2r4. 

Note that this list does not indicate the full set of VGA chips supported. For example, ­s3 includes the 86C801/5, 86C928, Vision864, and Vision964.  It is the job of vga(8) to recognize which particular chip is being used and to initialize it appropriately.

hwgc gc
Set the type of hardware graphics cursor being used. ­Gc is one of ark200pvhwgc, bt485hwgc, clgd542xhwgc, clgd546xhwgc, ct65545hwgc, cyber938xhwgc, hiqvideohwgc, mach64xxhwgc, mga2164whwgc, neomagichwgc, rgb524hwgc, s3hwgc, t2r4hwgc, tvp3020hwgc, and tvp3026hwgc.  A value of ­off disables the cursor.  There is no software cursor. 

palettedepth d
Set the number of bits of precision used by the VGA palette to d, which must be either ­6 or 8. 

­blank
Blank the screen. This consists of setting the hardware color map to all black as well as, on some controllers, setting the VGA hsync and vsync signals so as to turn off VESA DPMS-compliant monitors. The screen also blanks after 30 minutes of inactivity. The screen can be unblanked by moving the mouse.

blanktime minutes
Set the timeout before the screen blanks; the default is 30 minutes. If ­minutes is zero, blanking is disabled. 

hwaccel mode
Depending on whether ­mode is ­on or off, enable or disable whether hardware acceleration (currently for rectangle filling and moving) used by the graphics engine.  The default setting is on. 

hwblank mode
Depending on whether ­mode is ­on or off, enable or disable the use of DPMS blanking (see ­blank above). 

linear size align
Use a linear screen aperture of size ­size aligned on an align-byte boundary.

­drawinit
Initialize the graphics hardware. This must be sent after setting the type. 

Reading ­vgactl returns the current settings, one per line. 

EXAMPLES

The following disables hardware acceleration. 

echo -n ’hwaccel off’ >/dev/vgactl

SOURCE

­/sys/src/9/pc/devvga.c

SEE ALSO

arch(3), vga(8)

BUGS

There should be support for the hardware graphics cursor on the ­clgd54[23]x VGA controller chips. 

The hardware graphics cursor on the ­et4000 does not work in 2x8-bit mode. 

Plan 9  —  March 27, 2001