06 December 2019

ddcutil release 0.9.8 contains two changes of general interest:
- A new command line option, --sleep-multiplier, adjusts the time ddcutil pauses between sending a request to the monitor and reading from the monitor.
- A fix for the bug that certain mice would lock up during display detection.

The libddcutil shared library API has some minor extensions. For details, see Library Changes for Release 0.9.8.

Graphical user interface ddcui has reached beta status. Release 0.1.0 contains numermous improvements in the handling of particular VCP feature codes and the user interface generally. Prebuilt packages now exist for many platforms. See ddcui Overview.

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


ddcutil is a Linux program for managing monitor settings, such as brightness, color levels, and input source. Generally speaking, any settings 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 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.
  • Operation with AMD's proprietary video driver fglrx requires a specially built version of ddcutil. See Building with ADL Support.
  • 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 alpha 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:

Installation and Configuration:



Sanford Rockowitz rockowitz@minsoft.com