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 720×400 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 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 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 8×16 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
8×10 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
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 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.