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Command: vga | Section: 4 | Source: NetBSD | File: vga.4
VGA(4) FreeBSD Kernel Interfaces Manual VGA(4)
NAME
vga - 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
hardware. Currently, the driver runs the display with a 720x400 pixel
resolution. The VGA text-mode accelerator divides the display into
fixed-size character cells. The size of the character cells specifies
the number 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 720x400 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 8x16 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
feature, the "higher half" fonts of the former NetBSD/i386 pcvt driver
distribution 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 8x16 pixels, and a font consists of 256
characters.
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
8x10 pixels. For this mode to be useful, a font of that
character size must be downloaded.
80x40bf is analogously to "80x25bf" a version with 512 displayable
characters 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
8x8 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
characters 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
compatibility.
80x24bf Analogously, like "80x24" but with 512 character slots and 8
colors.
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 ALSO
isa(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
connected. 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.
FreeBSD 14.1-RELEASE-p8 May 4, 2003 FreeBSD 14.1-RELEASE-p8