If your graphics card is supported by /dev/i2c-* devices (see Appendix C, Supported graphics cards), you must load the i2c-dev module by typing, as root:
# modprobe i2c-dev
You must also load your graphics card framebuffer driver (for card-specific instructions see Appendix C, Supported graphics cards).
If you want to automatically load these modules when Linux starts, see your distribution's documentation.
To allow standard (i.e. non-root) users to use DDCcontrol, you must change permissions on /dev/i2c-*. This is done by typing, as root:
# chmod a+rw /dev/i2c-*
If i2c-dev or your graphics card's framebuffer modules are not available with your kernel, you can build your own kernel with the following options turned on (with recommend to build them as modules):