Twin cinema hd on an M1 mini

[Danwilderspin]

Hi all - proud owner of an M1 Mini I love it!

mans woth the addition of a collection of adapters I have my twin 27 cinema monitors working… there is one small issue though…

my setup is - usb-c to Mini DisplayPort and HDMI to Mini DisplayPort.

everything works as expected on the usbc connected screen on the hdmi however everything works except brightness control? If I adjust the brightness control on the hdmi screen it adjusts the other usbc screen. If I adjust usbc screen it updates usbc brightness as expected. I have plugged both USB ports (one from each screen) into the mac but can’t work this out - any ideas?

 

[joevt]

What method are you using to adjust brightness control on each display?

Is there a brightness control in the Displays preferences panel for each display? If so, does those brightness controls work?

 

[Danwilderspin]

Well there is a development - I just use the widget sliders on the top or the f1 f2 or shift f1 f2

development is that sometimes it works sometimes sometime sit doesn’t I need to look more but it may stop working after a sleep

 

[Danwilderspin]

so the is so weird. it is random which monitor will work with the brightness sliders - both sliders do the same monitor however if I unplug the usb plugs from both screen and plug them in again while the mini is on it works as it should with both sliders until I power off?