VGA(4) BSD Kernel Interfaces Manual VGA(4)NAMEvga — VGA graphics driver for wscons
SYNOPSIS
options VGA_CONSOLE_SCREENTYPE="??x??"
options VGA_CONSOLE_ATI_BROKEN_FONTSEL
vga0 at isa?
vga* at pci?
wsdisplay* at vga? console ?
DESCRIPTION
This driver handles VGA graphics hardware within the wscons(4) console
framework. It doesn't provide direct device driver entry points but
makes its functions available via the internal wsdisplay(4) interface.
The vga driver supports text-mode hardware acceleration on the VGA hard‐
ware. Currently, the driver runs the display with a 720×400 pixel reso‐
lution. The VGA text-mode accelerator divides the display into fixed-
size character cells. The size of the character cells specifies the num‐
ber of characters available on the screen and the resolution of the font.
The wsdisplay screen “types” supported by the vga driver are described by
the number of character cells available on the screen. See below for a
complete list of supported screen modes in the vga driver.
Each screen mode requires a suitable font to be loaded into the kernel by
the wsfontload(8) utility, before the screen can be used. The size of
the font and the screen mode must match for use on the 720×400 display.
For example, a screen mode with 80 columns and 40 rows requires a font
where each character is 8 pixels wide and 10 pixels high. The vga driver
can display fonts of the original IBM type and ISO-8859-1 encoded fonts.
A builtin font of 256 characters and 8×16 pixels is always present on the
VGA hardware.
The colour VGA hardware supports the display of 16 different colours at
the same time. It is possible with VGA colour systems to use fonts with
512 characters at any one time. This is due to the fact that with VGA
adapters one can specify an alternate font to be used instead of bright
letters (used for highlighting on the screen). As an experimental fea‐
ture, the “higher half” fonts of the former NetBSD/i386 pcvt driver dis‐
tribution can be used too if the kernel option “WSCONS_SUPPORT_PCVTFONTS”
was set at compile time. This is only useful with the “*bf” screen
types; a font containing the ASCII range of characters must be available
too on this screen.
Currently, the following screen types are supported:
80x25 This is the standard VGA text mode with 80 columns and 25 rows.
Sixteen different colors can be displayed at the same time.
Characters are 8×16 pixels, and a font consists of 256 charac‐
ters.
80x25bf is a modified version of the previous. It only allows 8 colors
to be displayed. In exchange, it can access two fonts at the
same time, so that 512 different characters can be displayed.
80x40 A text mode with 80 columns and 40 rows. Similar to the standard
mode, 16 colors and 256 characters are available. Characters are
8×10 pixels. For this mode to be useful, a font of that charac‐
ter size must be downloaded.
80x40bf is analogously to “80x25bf” a version with 512 displayable char‐
acters but 8 colors only.
80x50 A text mode with 80 columns and 50 rows. Similar to the standard
mode, 16 colors and 256 characters are available. Characters are
8×8 pixels. For this mode to be useful, a font of that character
size must be downloaded.
80x50bf is analogously to “80x25bf” a version with 512 displayable char‐
acters but 8 colors only.
80x24 is a variant of the “80x25” screen type which displays 24 lines
only. It uses the standard 8x16 VGA font. This mode might be
useful for applications which depend on closer DEC VT100 compati‐
bility.
80x24bf Analogously, like “80x24” but with 512 character slots and 8 col‐
ors.
If you have an Ati videocard and you are experiencing problems with fonts
other than 80x25, you can try to set options
VGA_CONSOLE_ATI_BROKEN_FONTSEL in you kernel configuration and see if it
helps.
The vga driver supports multiple virtual screens on one physical display.
The screens allocated on one display can be of different “types”. The
type is determined at the time the virtual screen is created and can't be
changed later. Screens are either created at kernel startup (then the
default type is used) or later with help of the wsconscfg(8) utility.
SEE ALSOisa(4), pcdisplay(4), pci(4), wscons(4), wsconscfg(8), wsfontload(8)BUGS
Only a subset of the possible text modes is supported.
VGA cards are supposed to emulate an MDA if a monochrome display is con‐
nected. In this case, the device will naturally not support colors at
all, but offer the capability to display underlined characters instead.
The “80x25bf”, “80x40bf”, “80x50bf” and “80x24bf” screen types will not
be available. This mode of operation has not been tested.
BSD May 4, 2003 BSD
