ref: a37a13074c443c7104016187daad1e8171f0adc8
dir: /sys/man/3/vga/
.TH VGA 3 .SH NAME vga \- VGA controller device .SH SYNOPSIS .nf .B bind #v /dev .B /dev/vgabios .B /dev/vgactl .B /dev/vgaovl .B /dev/vgaovlctl .fi .SH DESCRIPTION The VGA device allows configuration of a graphics controller on a PC. .B 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 .IR arch (3), it is used to implement configuration and setup of VGA controller cards. This is usually performed by .IR vga (8). .PP .B Vgabios provides read-only access to the low 640kB of memory, where the VGA and other BIOS ROMs are located. .PP Writing strings to .B vgactl configures the VGA device. The following are valid commands. .TP .BI size " X" x Y x "Z chan" Set the size of the screen image to be .I X pixels wide and .I Y pixels high. Each pixel is .I Z bits as specified by .IR chan , whose format is described in .IR image (6). .TP .BI actualsize " X" x Y Set the physical size of the display to be .I X pixels wide by .I Y pixels high. This message is optional; it is used to implement panning and to accommodate displays that require the in-memory screen image to have certain alignment properties. For example, a 1400x1050 screen with a 1408x1050 in-memory image will use .B "size 1408x1050 but .BR "actualsize 1400x1050" . .TP .BI panning " mode" Depending on whether .I mode is .B on or .BR off , enable or disable panning in a virtual screen. If panning is on and the screen's .B size is larger than its .BR actualsize , the displayed portion of the screen will pan to follow the mouse. Setting the panning mode after the first attach of the .B #i driver has no effect. .TP .BI type " ctlr" Set the type of VGA controller being used. .I Ctlr is one of .BR ark200pv , .BR clgd542x , .BR clgd546x , .BR ct65545 , .BR cyber938x , .BR hiqvideo , .BR mach64xx , .BR mga2164w , .BR neomagic , .BR nvidia , .BR s3 , and .BR t2r4 . .IP Note that this list does not indicate the full set of VGA chips supported. For example, .B s3 includes the 86C801/5, 86C928, Vision864, and Vision964. It is the job of .IR vga (8) to recognize which particular chip is being used and to initialize it appropriately. .TP .BI hwgc " gc" Set the type of hardware graphics cursor being used. .I Gc is one of .BR ark200pvhwgc , .BR bt485hwgc , .BR clgd542xhwgc , .BR clgd546xhwgc , .BR ct65545hwgc , .BR cyber938xhwgc , .BR hiqvideohwgc , .BR mach64xxhwgc , .BR mga2164whwgc , .BR neomagichwgc , .BR nvidiahwgc , .BR rgb524hwgc , .BR s3hwgc , .BR t2r4hwgc , .BR tvp3020hwgc , and .BR tvp3026hwgc . A value of .B off disables the cursor. There is no software cursor. .TP .BI palettedepth " d" Set the number of bits of precision used by the VGA palette to .IR d , which must be either .B 6 or .BR 8 . .TP .B 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. .TP .BI blanktime " minutes" Set the timeout before the screen blanks; the default is 30 minutes. If .I minutes is zero, blanking is disabled. .TP .BI hwaccel " mode" Depending on whether .I mode is .B on or .BR off , enable or disable whether hardware acceleration (currently for rectangle filling and moving) used by the graphics engine. The default setting is .BR on . .TP .BI softscreen " mode" Depending on whether .I mode is .B on or .BR off , enable or disable shadow framebuffer to reduce slow bus reads. Enabling .BI softscreen disables hardware acceleration. The default setting is .BR off except for the .BR vesa driver. .TP .BI hwblank " mode" Depending on whether .I mode is .B on or .BR off , enable or disable the use of DPMS blanking (see .B blank above). .TP .BI linear " size align" Use a linear screen aperture of size .I size aligned on an .IR align -byte boundary. .TP .B drawinit Initialize the graphics hardware. This must be sent after setting the .BR type . .PP Reading .B vgactl returns the current settings, one per line. .PP Some VGA cards support overlay graphics. Writing strings to .B vgaovlctl configures such cards. The following are valid overlay control commands: .TP .BI openctl opens the overlay device. .TP .BI configure " w h format" allocates resources inside the driver to support an overlay area of width .I w and height .I h pixels. Currently, the only supported .I format is .B YUYV packed. In .B YUYV two pixels are encoded by their separate Y values and their combined U and V values. The size of the two pixels is 32 bits. .TP .BI enable " x y w h" enables drawing data on the display through the overlay mode. The data is drawn at position .IR x , y and has a width and height of .IR w , h respectively. .TP .BI closectl terminates overlay control. .PP Overlay data can be written to .BR vgaovl . .SH EXAMPLES The following disables hardware acceleration. .IP .EX echo hwaccel off > /dev/vgactl .EE .SH SOURCE .B /sys/src/9/pc/devvga.c .SH SEE ALSO .IR arch (3), .IR vga (8) .SH BUGS The hardware graphics cursor on the .B et4000 does not work in 2x8-bit mode.