.TH VGA 8
.SH NAME
vga \- configure a VGA card
.SH SYNOPSIS
.B aux/vga
[
.B -BcdilpvV
]
[
.B -b
.I bios-string
]
[
.B -m
.I monitor
]
[
.B -x
.I file
]
[
.I mode
[
.I size
]
]
.SH DESCRIPTION
.I Vga
configures a VGA controller for various display sizes and depths.
Using the monitor type specified in
.B /env/monitor
(default
.BR vga )
and the
.I mode
given as argument
(default
.BR 640x480x1 ), 
.I vga
uses the database of known VGA controllers and monitors in
.B /lib/vgadb
(see
.IR vgadb (6))
to configure
the display via the devices provided by
.IR vga (3).
The options are:
.TP
.BI -b " bios-string"
use the VGA database entry corresponding to
.I bios-string
(e.g. 
\fL0xC0045="Stealth 64 DRAM Vers. 2.02"\fR)
rather than looking for identifying strings in the BIOS
memory.
.TP
.B -B
dump the BIOS memory (in hex) to standard output and exit.
.TP
.B -c
disable the use of the hardware graphics cursor.
.TP
.B -d
include the color palette in whatever actions are performed,
usually printing the contents.
.TP
.B -i
when used with
.B -p
display the register values that will be loaded.
.TP
.B -l
load the desired mode.
.TP
.BI -m " monitor"
override the
.B /env/monitor
value.
.B /env/monitor
is usually set by including it in the
.B plan9.ini
file read by the PC boot program
.IR 9boot (8).
.TP
.B -p
print the current or expected register values at appropriate points depending on
other options.
.TP
.B -v
print a trace of the functions called.
.TP
.B -V
print a verbose trace of the functions called.
.TP
.BI -x " file"
use 
.I file
as the VGA database rather than
.BR /lib/vgadb .
.PP
.I Mode
is of the form
.IB X x Y x Z
, where
.IR X ,
.IR Y ,
and
.I Z
are numbers specifying the display height, width, and depth respectively.
The mode must appear in 
.B /lib/vgadb
as a value for one of the monitor entries.
The usual modes are
.BR 640x480x[18] ,
.BR 800x600x[18] ,
.BR 1024x768x[18][i] ,
.BR 1280x1024x[18][i] ,
.BR 1376x1024x8 ,
and
.BR 1600x1200x8 .
A trailing
.L i
indicates interlaced operation.
The default mode is
.BR 640x480x8 .
.I Size
is of the form
.I X x Y
and configures the display to have a virtual
screen of the given size.
The physical screen will pan to follow the mouse.
This is useful on displays with small screens,
such as laptops, but can be confusing.
.PP
Using the monitor name
.B vesa
instructs
.I vga
to use VESA BIOS calls to configure the display.
Also, if our VGA controller can't be found in
.IR vgadb ,
.I vga
will try the VESA calls.
There are no entries for the
.B vesa
monitor in 
.IR vgadb .
For a list of available VESA modes, use
.IP
.EX
aux/vga -m vesa -p
.EE
.PP
Loading the special mode
.BR text :
.IP
.EX
aux/vga -l text
.EE
.PP
switches out of graphics mode back into text mode.
It uses the VESA BIOS.
.SH EXAMPLES
Change the display resolution:
.IP
.EX
aux/vga -l 1600x1200x8
.EE
.PP
Print the current VGA controller registers.
It is usually best to redirect the output of a
.B -p
command to a file to prevent confusion caused by using the VGA
controller while trying to dump its state:
.IP
.EX
aux/vga -p >/tmp/x
.EE
.PP
Force the VGA controller to a known state:
.IP
.EX
aux/vga -m vga -l
.EE
.PP
Print the current VGA controller state and what would be loaded
into it for a new resolution, but don't do the load:
.IP
.EX
aux/vga -ip 1376x1024x8 >/tmp/x
.EE
.PP
.SH FILES
.TF /env/monitor
.TP
.B /env/monitor
display type (default
.IR vga ).
.TP
.B /lib/vgadb
VGA configuration file.
.SH SOURCE
.B /sys/src/cmd/aux/vga
.SH SEE ALSO
.IR vga (3),
.IR vgadb (6),
.IR 9boot (8)
.SH BUGS
.B Aux/vga
makes every effort possible to verify that the mode it is about
to load is valid and will bail out with an error message 
before setting any registers if it encounters a problem.
However, things can go wrong, especially when playing with a
new VGA controller or monitor setting.
It is useful in such cases to have
the above command for setting the controller to a known state
at your fingertips.