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       fbset - show and modify frame buffer device settings


       fbset [options] [mode]


       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>
       or 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

       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

              --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/fb/0 or /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 bitfield colors:

              -rgba <red,green,blue,alpha>
                     each in length or length/offset color format

       Display geometry:

              -xres <value>
                     set visible horizontal resolution (in pixels)

              -yres <value>
                     set visible vertical resolution (in pixels)

              -vxres <value>
                     set virtual horizontal resolution (in pixels)

              -vyres <value>
                     set virtual vertical resolution (in pixels)

              -depth <value>
                     set display depth (in bits per pixel)

              -nonstd <value>
                     select nonstandard video mode

              --geometry, -g ...
                     set all geometry parameters at once in  the
                     order   <xres>   <yres>   <vxres>   <vyres>
                     <depth>, e.g.  -g 640 400 640 400 4

                     make  the  physical  resolution  match  the
                     virtual resolution

       Display timings:

              -pixclock <value>
                     set   the   length   of   one   pixel   (in
                     picoseconds). Note that  the  frame  buffer
                     device may only support some pixel lengths

              -left <value>
                     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.  -t 35242 64
                     96 35 12 112 2

       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

              -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

              -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

              -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

              fbset -fb /dev/fb0 vga

       and make the used frame buffer device known to X:

              export FRAMEBUFFER=/dev/fb0




       fb.modes(5), fbdev(4), /usr/share/doc/fbset/FAQ


       Geert Uytterhoeven <>

       Roman Zippel <>
              man files