Reading Contrast & Brighness doesn't work on Sierra

[paxl13]

Hi,

Title says it all, it used to work on El Capitain, doesn't work on Sierra anymore.

[xlarue@SYS0758 ddcctl (master %)]$ ./ddcctl -d 1 -c ?
D: NSScreen #724069582 (1920x1080 0°) HiDPI
I: found 1 display
I: polling display 1's EDID
I: got edid.serial: G3D7F62J0NCL
I: got edid.name: DELL P2415Q
D: action: c: ?
D: querying VCP control: #18 =?
E: No data after 10 tries!
E: DDC send command failed!
E: VCP control #18 (0x12) = current: 0, max: 0
[xlarue@SYS0758 ddcctl (master %)]$ ./ddcctl -d 1 -b ?
D: NSScreen #724069582 (1920x1080 0°) HiDPI
I: found 1 display
I: polling display 1's EDID
I: got edid.serial: G3D7F62J0NCL
I: got edid.name: DELL P2415Q
D: action: b: ?
D: querying VCP control: #16 =?
E: No data after 10 tries!
E: DDC send command failed!
E: VCP control #16 (0x10) = current: 0, max: 0
[xlarue@SYS0758 ddcctl (master %)]$

Any idea?

[kfix]

I use master on both Sierra and El Cap & I can't reproduce.