3 vga \- VGA controller device
14 The VGA device allows configuration of a graphics controller
17 allows control over higher-level settings such as display height, width, depth,
18 controller and hardware-cursor type.
19 Along with the I/O-port registers
22 it is used to implement configuration and setup of VGA controller cards.
23 This is usually performed by
27 provides read-only access to the low 640kB of memory,
28 where the VGA and other BIOS ROMs are located.
32 configures the VGA device.
33 The following are valid commands.
35 .BI size " X" x Y x "Z chan"
36 Set the size of the screen image to be
46 whose format is described in
49 .BI actualsize " X" x Y
50 Set the physical size of the display to be
55 This message is optional;
56 it is used to implement panning and to accommodate
57 displays that require the in-memory screen image
58 to have certain alignment properties.
59 For example, a 1400x1050 screen with a 1408x1050 in-memory image
63 .BR "actualsize 1400x1050" .
72 enable or disable panning in a virtual screen.
73 If panning is on and the screen's
77 the displayed portion of the screen will pan to follow the mouse.
78 Setting the panning mode after the first attach of the
83 Set the type of VGA controller being used.
100 Note that this list does not indicate the full set of VGA chips
101 supported. For example,
103 includes the 86C801/5, 86C928, Vision864, and Vision964.
106 to recognize which particular chip is being used and to initialize it
110 Set the type of hardware graphics cursor being used.
133 There is no software cursor.
135 .BI palettedepth " d"
136 Set the number of bits of precision used by the
146 This consists of setting the hardware
147 color map to all black as well as, on some controllers, setting the
148 VGA hsync and vsync signals so as to turn off
149 VESA DPMS-compliant monitors.
150 The screen also blanks after 30 minutes of inactivity.
151 The screen can be unblanked by moving the mouse.
153 .BI blanktime " minutes"
154 Set the timeout before the
155 screen blanks; the default is 30 minutes.
158 is zero, blanking is disabled.
167 enable or disable whether hardware acceleration
168 (currently for rectangle filling and moving)
169 used by the graphics engine.
170 The default setting is
173 .BI softscreen " mode"
180 enable or disable shadow framebuffer to reduce
181 slow bus reads. Enabling
183 disables hardware acceleration. The default setting is
196 enable or disable the use of DPMS blanking
201 .BI linear " size align"
202 Use a linear screen aperture of size
209 Initialize the graphics hardware.
210 This must be sent after setting the
215 returns the current settings, one per line.
217 Some VGA cards support overlay graphics.
220 configures such cards.
221 The following are valid overlay control commands:
224 opens the overlay device.
226 .BI configure " w h format"
227 allocates resources inside the driver to support an overlay area
232 pixels. Currently, the only supported
239 two pixels are encoded by their separate Y values
240 and their combined U and V values.
241 The size of the two pixels is 32 bits.
243 .BI enable " x y w h"
244 enables drawing data on the display through the overlay mode. The data
247 and has a width and height of
252 terminates overlay control.
254 Overlay data can be written to
257 The following disables hardware acceleration.
260 echo hwaccel off > /dev/vgactl
263 .B /sys/src/9/pc/devvga.c
268 The hardware graphics cursor on the
270 does not work in 2x8-bit mode.