The
driver is a generic video card driver which provides access to
video cards.
This driver is required for the console driver
syscons(4).
The console driver will call the
driver to manipulate video hardware (changing video modes, loading font, etc).
The
driver supports the standard video cards: MDA, CGA, EGA and VGA.
In
addition, the driver can utilize VESA BIOS extensions if the video card
supports them.
VESA support can either be statically included in the kernel
or can be loaded as a separate module.
In order to statically link the VESA support to the kernel, the
VESA
option (see below) must be defined in the kernel configuration file.
The
vesa
module can be dynamically loaded into the kernel using
kldload(8).
DRIVER CONFIGURATION
Kernel Configuration Options
The following kernel configuration options
(see
config(8))
can be used to control the
driver.
These options provide compatibility with certain VGA cards.
VGA_ALT_SEQACCESS
You may want to try this option if the mouse pointer is not drawn correctly
or the font does not seem to be loaded properly on the VGA card.
However, it may cause flicker on some systems.
VGA_SLOW_IOACCESS
Older VGA cards may require this option for proper operation.
It makes the driver perform byte-wide I/O to VGA registers and
slow down a little.
VGA_WIDTH90
This option enables 90 column modes: 90x25, 90x30, 90x43, 90x50, 90x60.
These modes are not always supported by the video card and the display.
It is highly likely that LCD display cannot work with these modes.
The following options add optional features to the driver.
VESA
Add VESA BIOS support to the driver.
If the VGA card has the VESA BIOS extension 1.2 or later,
this option will utilize the VESA BIOS service to switch to high
resolution modes.
VESA_DEBUG=N
Set the VESA support debug level to
Fa N .
The default value is zero, which suppresses all debugging output.
The following options will remove some features from the
driver and save kernel memory.
VGA_NO_FONT_LOADING
The
driver can load software font to EGA and VGA cards.
This option removes this feature.
Note that if you use this option and
still wish to use the mouse on the console then you must also use the
SC_ALT_MOUSE_IMAGE
option.
See
syscons(4).
VGA_NO_MODE_CHANGE
This option prevents the driver from changing video modes.
EXAMPLES
Your kernel configuration should normally have:
"device vga"
And you need the following line in
/boot/device.hints
hint.vga.0.at="isa"
The following lines should be included in the kernel configuration file
in order to enable the VESA BIOS Extension support.
"options VESA"
"device vga"
If you do not want VESA support included in the kernel, but
want to use occasionally, do not add the
VESA
option.
And load the
vesa
module as desired:
"VESA BIOS Extension (VBE)"
Video Electronics Standards Association
HISTORY
The
driver first appeared in
Fx 3.1 .
AUTHORS
An -nosplit
The
driver was written by
An S/oren Schmidt Aq sos@FreeBSD.org
and
An Kazutaka Yokota Aq yokota@FreeBSD.org .
This manual page was written by
An Kazutaka Yokota .
