fbset - show and modify frame buffer device settings
SYNOPSIS
fbset [options] [mode]
DESCRIPTION
This documentation is out of date!!
fbset is a system utility to show or change the settings
of the frame buffer device. The frame buffer device pro
vides a simple and unique interface to access different
kinds of graphic displays.
Frame buffer devices are accessed via special device nodes
located in the /dev directory. The naming scheme for these
nodes is always fb<n>, where n is the number of the used
frame buffer device.
fbset uses an own video mode database located in
/etc/fb.modes. An unlimited number of video modes can be
defined in this database. For further information see
fb.modes(5).
OPTIONS
If no option is given, fbset will display the current
frame buffer settings.
General options:
--help, -h
display an usage information
--now, -n
change the video mode immediately. If no
frame buffer device is given via -fb , then
this option is activated by default
--show, -s
display the video mode settings. This is
default if no further option or only a frame
buffer device via -fb is given
--info, -i
display all available frame buffer informa
tion
--verbose, -v
display information what fbset is currently
doing
--version, -V
display the version information about fbset
display the timing information as it's
needed by XFree86
Frame buffer device nodes:
-fb <device>
device gives the frame buffer device node.
If no device via -fb is given, /dev/fb0 is
used
Video mode database:
-db <file>
set an alternative video mode database file
(default is /etc/fb.modes), see also
fb.modes(5)
Display geometry:
-xres <value>
set visible horizontal resolution (in pix
els)
-yres <value>
set visible vertical resolution (in pixels)
-vxres <value>
set virtual horizontal resolution (in pix
els)
-vyres <value>
set virtual vertical resolution (in pixels)
-depth <value>
set display depth (in bits per pixel)
--geometry, -g ...
set all geometry parameters at once in the
order <xres> <yres> <vxres> <vyres> <depth>,
e.g. -g 640 400 640 400 4
-match
make the physical resolution match the vir
tual resolution
Display timings:
-pixclock <value>
set the length of one pixel (in picosec
onds). Note that the frame buffer device may
only support some pixel lengths
set left margin (in pixels)
-right <value>
set right margin (in pixels)
-upper <value>
set upper margin (in pixel lines)
-lower <value>
set lower margin (in pixel lines)
-hslen <value>
set horizontal sync length (in pixels)
-vslen <value>
set vertical sync length (in pixel lines)
--timings, -t ...
set all timing parameters at once in the
order <pixclock> <left> <right> <upper>
<lower> <hslen> <vslen>, e.g. -g 35242 64
96 35 12 112 2
Display flags:
-hsync {low|high}
set the horizontal sync polarity
-vsync {low|high}
set the vertical sync polarity
-csync {low|high}
set the composite sync polarity
-extsync {false|true}
enable or disable external resync. If
enabled the sync timings are not generated
by the frame buffer device and must be pro
vided externally instead. Note that this
option may not be supported by every frame
buffer device
-bcast {false|true}
enable or disable broadcast modes. If
enabled the frame buffer generates the exact
timings for several broadcast modes (e.g.
PAL or NTSC). Note that this option may not
be supported by every frame buffer device
-laced {false|true}
enable or disable interlace. If enabled the
display will be split in two frames, each
frame contains only even and odd lines
played alternating, this way twice the lines
can be displayed and the vertical frequency
for the monitor stays the same, but the vis
ible vertical frequency gets halved
-double {false|true}
enable or disable doublescan. If enabled
every line will be displayed twice and this
way the horizontal frequency can easily be
doubled, so that the same resolution can be
displayed on different monitors, even if the
horizontal frequency specification differs.
Note that this option may not be supported
by every frame buffer device
Display positioning:
-move {left|right|up|down}
move the visible part of the display in the
specified direction
-step <value>
set step size for display positioning (in
pixels or pixel lines), if -step is not
given display will be moved 8 pixels hori
zontally or 2 pixel lines vertically
EXAMPLE
To set the used video mode for X insert the following in
rc.local:
fbset -fb /dev/fb0 vga
and make the used frame buffer device known to X:
export FRAMEBUFFER=/dev/fb0
FILES
/dev/fb*
/etc/fb.modes
SEE ALSO
fb.modes(5), fbdev(4)
AUTHORS
Geert Uytterhoeven <Geert.Uytterhoeven@cs.kuleuven.ac.be>
Roman Zippel <zippel@fh-brandenburg.de>
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