$ sudo ddccontrol -p -r 0x10 -w 50
ddccontrol version 0.4.2
Copyright 2004-2005 Oleg I. Vdovikin (oleg@cs.msu.su)
Copyright 2004-2006 Nicolas Boichat (nicolas@boichat.ch)
This program comes with ABSOLUTELY NO WARRANTY.
You may redistribute copies of this program under the terms of the GNU General Public License.

Probing for available monitors....I/O warning : failed to load external entity "/usr/share/ddccontrol-db/monitor/LGD046F.xml"
Document not parsed successfully.
....
Detected monitors :
 - Device: dev:/dev/i2c-3
   DDC/CI supported: No
   Monitor Name: VESA standard monitor
   Input type: Digital
No monitor supporting DDC/CI available.
If your graphics card need it, please check all the required kernel modules are loaded (i2c-dev, and your framebuffer driver).