xvidtune - video mode tuner for Xorg
xvidtune [ -show | -prev | -next | -unlock ]
  [ -toolkitoption ... ]
Xvidtune is a client interface to the X server video mode extension
  (XFree86-VidModeExtension).
When given one of the non-toolkit options, xvidtune provides a
    command line interface to either print or switch the video mode.
Without any options (or with only toolkit options) it presents the
    user with various buttons and sliders that can be used to interactively
    adjust existing video modes. It will also print the settings in a format
    suitable for inclusion in an xorg.conf file.
Normally the Xorg X servers only allow changes to be made with the
    XFree86-VidModeExtension from clients connected via a local connection
  type.
Note: The original mode settings can be restored by pressing the
    `R' key, and this can be used to restore a stable screen in situations where
    the screen becomes unreadable.
The available buttons are:
Left
Right
Up
Down
Adjust the video mode so that the display will be moved
  in the appropriate direction.
Wider
Narrower
Shorter
Taller
Adjust the video mode so that the display size is altered
  appropriately.
  - Quit
- Exit the program.
- Apply
- Adjust the current video mode to match the selected settings.
- Auto
- Cause the Up/Down/Right/Left, Wider/Narrower/Shorter/Taller, Restore, and
      the special S3 buttons to be applied immediately. This button can be
      toggled.
- Test
- Temporarily switch to the selected settings.
- Restore
- Return the settings to their original values.
- Fetch
- Query the server for its current settings.
- Show
- Print the currently selected settings to stdout in xorg.conf
      "Modeline" format. The primary selection is similarly set.
- Next
- Switch the Xserver to the next video mode.
- Prev
- Switch the Xserver to the previous video mode.
For some S3-based cards (964 and 968) the following are also
    available:
  - InvertVCLK
- Change the VCLK invert/non-invert state.
- EarlySC
- Change the Early SC state. This affects screen wrapping.
BlankDelay1
BlankDelay2
Set the blank delay values. This affects screen wrapping.
  Acceptable values are in the range 0-7. The values may be incremented or
  decremented with the `+' and `-' buttons, or by pressing the `+' or `-' keys
  in the text field.
For S3-864/868 based cards InvertVCLK and
    BlankDelay1 may be useful. For S3 Trio32/Trio64 cards only
    InvertVCLK is available. At the moment there are no default settings
    available for these chips in the video mode extension and thus this feature
    is disabled in xvidtune. It can be enabled by setting any of the optional S3
    commands in the screen section of xorg.conf, e.g. using
blank_delay "∗" 0
xvidtune accepts the standard X Toolkit command line options as well as
  the following:
  - -show
- Print the current settings to stdout in xorg.conf "Modeline"
      format and exit.
- -prev
- Switch the Xserver to the previous video mode.
- -next
- Switch the Xserver to the next video mode.
- -unlock
- Normally, xvidtune will disable the switching of video modes via
      hot-keys while it is running. If for some reason the program did not exit
      cleanly and they are still disabled, the program can be re-run with this
      option to re-enable the mode switching key combinations.
xrandr(1), Xorg(1), xorg.conf(5).
Kaleb S. Keithley, X Consortium.
Additions and modifications by Jon Tombs, David Dawes, and Joe Moss.
X Error handling, i.e. when the server does not allow xvidtune clients to write
  new modes, could be better.