09 July 2020

Branch master on github was out of sync with the reference tarball and prebuilt packages on launchpad, COPR, and the openSUSE Build Service. The missing changes have been pushed to the master branch. If you have already built release 0.9.9 from the github master branch, pull the changes and rebuild.

28 June 2020

ddcui release 0.1.2 is an emergency bug fix release.

  • Combo boxes for simple Non-Continous features were empty instead of showing the currently selected value and list of allowed values.

24 June 2020

ddcutil release 0.9.9 contains two changes of general interest:

  • A new command line option, --less-sleep eliminates many of the delays between the time that ddcutil receives a DDC response from a display and sends the next request, improving performance.
  • Support for AMD's old proprietary fglrx driver has been dropped.

The libddcutil shared libray has non-upwardly compatible changes. For details, see Shared Library Changes for Release 0.9.9.

ddcui release 0.1.1 adds additional features and has numerous changes in the "fit and finish" category. In particular:

  • Command line options for starting ddcui, corresponding to settings in the Option dialogs, and (if multiple monitors) the initlal monitor selected.
  • The Feature Selection Dialog, along with command line option --custom-feature-set, enable the user to specify the VCP features to be shown.
  • Better handling of error conditions
  • Better Help text

ddcui release 0.1.1 requires ddcutil 0.9.9.

For general information about the graphical user interface, see ddcui.

For a complete list of ddcutil changes and bug fixes, see Release Notes.
For ddcui changes and bug fixes, see ddcui Release Notes.
Prior announcements can be found here.

Lastly, this website has been extensively revised to reflect the current state of ddcutil and ddcui.

Note: Prebuilt packages are now available for ddcutil 0.9.9.


ddcutil is a Linux program for managing monitor settings, such as brightness, color levels, and input source. Generally speaking, any setting that can be changed by pressing buttons on the monitor can be modified by ddcutil.

ddcutil primarily uses DDC/CI (Display Data Channel Command Interface) to communicate with monitors implementing MCCS (Monitor Control Command Set) over I2C. Normally, the video driver for the monitor exposes the I2C channel as devices named /dev/i2c-n. Alternatively, there is support for monitors (such as Eizo ColorEdge displays) that implement MCCS using a USB connection. See USB Connected Monitors.

A particular use case for ddcutil, and the one that inspired its development, is as part of color profile management. Monitor calibration is relative to the monitor color settings currently in effect, e.g. red gain. ddcutil allows color related settings to be saved at the time a monitor is calibrated, and then restored when the calibration is applied.


  • ddcutil does not support laptop displays, which are controlled using a special API, not I2C.
  • Generally speaking, ddcutil can be built in a virtual machine, but will not run in a VM. This is because the virtual video drivers do not implement I2C. However, if the VM is connected to a separate video card and is running a non-virtualized driver for the card in passthru mode, then ddcutil will work.
  • Nvidia's proprietary video driver may require special configuration. See Special Nvidia Driver Settings.
  • Reading and writing Table type features is implemented but untested. See Table Features

ddcutil is released under the GNU Public License, V2 (GPLV2). The source is hosted on Github.

General support questions are best directed to the issue tracker on Github. Use of that forum allows everyone to benefit from individual questions and ideas. For details, see Technical Support.


ddcui is a graphical user interface to ddcutil, built using Qt. It is currently beta level code. For further information, see ddcui Overview.

ddcui is released under the GNU Public License, V2 (GPLV2). The source is hosted on Github.

ddcui questions should also be directed the to the ddcutil issue tracker on Github.


Using ddcutil:

Commands and Options: - Detailed command and option documentation(command_detail.md)

Installation and Configuration:



Sanford Rockowitz rockowitz@minsoft.com