Description:

ddcutil is a program for querying and changing monitor settings, such
as brightness and color levels.

ddcutil uses DDC/CI 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. There
is also support for monitors (such as Apple Cinema and Eizo
ColorEdge) that implement MCCS using a USB connection.

A particular use case for ddcutil 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.