3 vga \- VGA controller device
13 The VGA device allows configuration of a graphics controller
16 allows control over higher-level settings such as display height, width, depth,
17 controller and hardware-cursor type.
18 Along with the I/O-port registers
21 it is used to implement configuration and setup of VGA controller cards.
22 This is usually performed by
27 configures the VGA device.
28 The following are valid commands.
30 .BI size " X" x Y x "Z chan"
31 Set the size of the screen image to be
41 whose format is described in
44 .BI actualsize " X" x Y
45 Set the physical size of the display to be
50 This message is optional;
51 it is used to implement panning and to accommodate
52 displays that require the in-memory screen image
53 to have certain alignment properties.
54 For example, a 1400x1050 screen with a 1408x1050 in-memory image
58 .BR "actualsize 1400x1050" .
67 enable or disable panning in a virtual screen.
68 If panning is on and the screen's
72 the displayed portion of the screen will pan to follow the mouse.
73 Setting the panning mode after the first attach of the
78 Set the type of VGA controller being used.
103 Note that this list does not indicate the full set of VGA chips
104 supported. For example,
106 includes the 86C801/5, 86C928, Vision864, and Vision964.
109 to recognize which particular chip is being used and to initialize it
113 Set the type of hardware graphics cursor being used.
145 .BI palettedepth " d"
146 Set the number of bits of precision used by the
161 enable or disable whether hardware acceleration
162 (currently for rectangle filling and moving)
163 used by the graphics engine.
164 The default setting is
167 .BI softscreen " mode"
174 enable or disable shadow framebuffer to reduce
175 slow bus reads. Enabling
177 disables hardware acceleration. The default setting is
190 enable or disable the use of DPMS blanking
194 .BI linear " size align"
195 Use a linear screen aperture of size
202 Initialize the graphics hardware.
203 This must be sent after setting the
208 returns the current settings, one per line.
210 Some VGA cards support overlay graphics.
213 configures such cards.
214 The following are valid overlay control commands:
217 opens the overlay device.
219 .BI configure " w h format"
220 allocates resources inside the driver to support an overlay area
225 pixels. Currently, the only supported
232 two pixels are encoded by their separate Y values
233 and their combined U and V values.
234 The size of the two pixels is 32 bits.
236 .BI enable " x y w h"
237 enables drawing data on the display through the overlay mode. The data
240 and has a width and height of
245 terminates overlay control.
247 Overlay data can be written to
250 The following disables hardware acceleration.
253 echo hwaccel off > /dev/vgactl
256 .B /sys/src/9/pc/devvga.c
261 The hardware graphics cursor on the
263 does not work in 2x8-bit mode.