TH VGA 3
SH NAME
vga \- VGA controller device
SH SYNOPSIS
nf
B bind #v /dev
B /dev/vgactl
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
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;
if this size is smaller than that specified in the
I size
message, the screen will pan to follow the mouse.
This is useful on systems with small displays, such as laptops.
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 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 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 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.
SH EXAMPLES
The following disables hardware acceleration.
IP
EX
echo -n '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
There should be support for the hardware graphics cursor on the
B clgd54[23]x
VGA controller chips.
PP
The hardware graphics cursor on the
B et4000
does not work in 2x8-bit mode.
