My monitor is a Dell P2715Q, and it does support DDC/CI (presumably). It's connected to my computer with a DisplayPort, and I'm trying to change the brightness from my computer, but it neither works on Windows nor Ubuntu.
I'm using Intel HD 530 integrated graphics, and supposedly, the drivers should support DDC/CI over DisplayPort. The "DDC/CI" option in the monitor's OSD is set to "enabled".
When I try to change the brightness on either Windows or Ubuntu, there is no option to do so where it would normally be. On Linux, I'm also testing with a program called
ddccontrol, and when I run
ddccontrol -p, it says: "No monitor supporting DDC/CI available".