Problem w/ dual LG 5k monitors

[rob_payne]

Shout out to see if others have had the problem when connecting two LG ultrafine 5k monitors to a MBP using the top most ports either side (as directed) where the brightness controls only control the last screen connected using either the keyboard or system preferences.

When adjusting the brightness the adjustment icon appears to show it reducing on the correct screen but the actual brightness changes on the other one. Looks like a bug to me.

Called Apple which was a complete waste of an hour as their expert suggested re-installing the OS ?

This is a real shame as the screens are great for development but the unequal brightness and in fact seems to reset itself to maximum after sleep/wake/hibernate each time.

Any suggestions from anyone?

 

[tommiy]

Sounds abut right for Catalina. There are alot of problems with Catalina handling external monitors. Depending upon your MAC I'd suggest going to High Sierra as it was the last stable OS with external monitors that I am aware of. You could try Mojave but it had a Window Server/Kernel bug with Night Shift with external monitors and also externally polling them when asleep. I suppose the very short answer is if possible try an earlier OS.

 

[rob_payne]

Thanks for the idea. I’ll reserve that for last resort though. Wouldn’t be such a problem if LG monitors had some form of physical controls but all software controlled.

 

[ducknalddon]

It might be worth trying to set it from the Display section of System Preferences.

 

[rob_payne]

It might be worth trying to set it from the Display section of System Preferences.

Thanks - but I tried this - with two external lg monitors, haven’t tried other makes, the brightness controller slider appears on the respective preferences panel for each screen but whichever one you choose they only adjust the last connected screen, same as with the Fn keys option.