fbset - show and modify frame buffer device settings
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<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).
If no option is given, fbset will display the current frame
buffer settings.
General options:
- --help, -h
- display an usage information
- --test
- don't change, just test whether the mode is valid
- --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:
- --all, -a
- change all virtual consoles on this device
- -fb <device>
- device gives the frame buffer device node. If no device via
-fb is given, /dev/fb0 is used
Video mode database:
Display bitfield colors:
Display geometry:
Display timings:
Display flags:
- -accel {false|true}
- set hardware text acceleration enable
- -hsync {low|high}
- set the horizontal sync polarity
- -vsync {low|high}
- set the vertical sync polarity
- -csync {low|high}
- set the composite sync polarity
- -gsync {false|true}
- set synch on green
- -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
- -sync <value>
- set custom sync flags. If specified, this value is bitwise or-ed to the
other sync flags. This is useful for drivers that use custom sync
flags
- -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
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 horizontally or 2
pixel lines vertically
To set the used video mode for X insert the following in
rc.local:
fbset -fb /dev/fb0 640x480-60
and make the used frame buffer device known to X:
export FRAMEBUFFER=/dev/fb0