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fbset(8) Linux frame buffer utils fbset(8)
NAME
fbset - show and modify frame buffer device settings
SYNOPSIS
fbset [options] [mode]
DESCRIPTION
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fbset is a system utility to show or change the settings of the frame
buffer device. The frame buffer device provides 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,
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 information
--verbose, -v
display information what fbset is currently doing
--version, -V
display the version information about fbset
--xfree86, -x
display the timing information as it's needed by XFree86
Frame buffer device nodes:
-fb
device gives the frame buffer device node. If no device
via -fb is given, /dev/fb0 is used
Video mode database:
-db
set an alternative video mode database file (default is
/etc/fb.modes), see also fb.modes(5)
Display geometry:
-xres
set visible horizontal resolution (in pixels)
-yres
set visible vertical resolution (in pixels)
-vxres
set virtual horizontal resolution (in pixels)
-vyres
set virtual vertical resolution (in pixels)
-depth
set display depth (in bits per pixel)
--geometry, -g ...
set all geometry parameters at once in the order
, e.g. -g 640 400 640 400
4
-match
make the physical resolution match the virtual resolu-
tion
Display timings:
-pixclock
set the length of one pixel (in picoseconds). Note that
the frame buffer device may only support some pixel
lengths
-left
set left margin (in pixels)
-right
set right margin (in pixels)
-upper
set upper margin (in pixel lines)
-lower
set lower margin (in pixel lines)
-hslen
set horizontal sync length (in pixels)
-vslen
set vertical sync length (in pixel lines)
--timings, -t ...
set all timing parameters at once in the order clock> ,
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 provided 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 respectively. These two frames will be
displayed alternating, this way twice the lines can be
displayed and the vertical frequency for the monitor
stays the same, but the visible 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 horizon-
tal 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
set step size for display positioning (in pixels or
pixel lines), if -step is not given display will be
moved 8 pixels horizontally 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
Roman Zippel
man files
local July 1998 fbset(8)
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