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
209 to either disable scaling, scale to full screen, or
210 to scale while preserving aspect ratio.
212 .BI linear " size align"
213 Use a linear screen aperture of size
220 Initialize the graphics hardware.
221 This must be sent after setting the
226 returns the current settings, one per line.
228 Some VGA cards support overlay graphics.
231 configures such cards.
232 The following are valid overlay control commands:
235 opens the overlay device.
237 .BI configure " w h format"
238 allocates resources inside the driver to support an overlay area
243 pixels. Currently, the only supported
250 two pixels are encoded by their separate Y values
251 and their combined U and V values.
252 The size of the two pixels is 32 bits.
254 .BI enable " x y w h"
255 enables drawing data on the display through the overlay mode. The data
258 and has a width and height of
263 terminates overlay control.
265 Overlay data can be written to
268 The following disables hardware acceleration.
271 echo hwaccel off > /dev/vgactl
274 .B /sys/src/9/pc/devvga.c
279 The hardware graphics cursor on the
281 does not work in 2x8-bit mode.