Configure /dev/i2c-* devices

Note

/dev/i2c-* devices are only working with kernel 2.6 or greater.

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.

On systems not using devfs, even after loading framebuffer and i2c-dev modules, the devices /dev/i2c/* or /dev/i2c-* does not exists. On Debian, these devices are created using this command :

# /sbin/MAKEDEV i2c

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-*

Kernel configuration options

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):

  • Devices drivers->I2C support.
  • Devices drivers->I2C support->I2C device interface.
  • Devices drivers->Graphics support->Framebuffer support.
  • and a specific driver for your graphic card (see Appendix C, Supported graphics cards).

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