Macbook Pro Retina (Late 2013), ADC with i1Profiler w/i1PhotoPro2

[rxchaos]

On my MacBookProRetina (Late2013 model) ADC stopped working when used with i1Profiler (v. 1.66) and i1PhotoPro2.  On the Measurement screen under Display Hardware Setup I've enabled Automatic Display Control (ADC). When I start start the measurement process i1Profiler reverts to requiring you to manually adjust the brightness levels.  In i1Profiler I set the Luminance to 120 and with the manually adjusting the brightness it's hard to achieve the desired luminance. 

I'm running MacOS 10.11.6 (ElCapitan), i1Profiler version is 1.66.  ADC used to work and somehow stopped working. Not sure if this happened after a MacOS udate some months ago.

Any thoughts?

[rxchaos]

From posts on other user groups it appears that Apple have broken 'DDC/CI'  communications that enable calibration devices to control the display brightness. This apparently has been broken since MacOS version10.5.5.  There have been many OS releases since and it appears Apple have no intention of fixing this.

[GWGill]

From posts on other user groups it appears that Apple have broken 'DDC/CI'  communications that enable calibration devices to control the display brightness.

If true, that would also mean that calibration software can't upload in-display calibration curves via DDC/CI either.