I can’t say for sure what the problem is in your case, but it’s definitely not a problem in Lunar.
All the app does is call a macOS function called IOAVServiceWriteI2C to send a standard DDC message to the monitor (something like “set brightness to 30”)
In your case, either the dongle or the monitor reacts unexpectedly to that message. What should happen is that the dongle should simply forward that message as it is to the monitor and the monitor should have firmware logic to interpret it correctly and either set the brightness to the sent value, or not do anything.
That’s why Apple will never implement native brightness changing using DDC.
They can’t risk having users come with problems like this one in the press, because the monitor or hub/dock does something funny with the DDC message and crashes.
Lunar can also function in software mode using gamma by following the instructions here: https://lunar.fyi/faq#bad-ddc
That mode will never crash a monitor because it doesn’t send any data to it.
I've tinkered around a bit and found that with another dongle that uses displayport everything works fine. Changing volume and brightness from the keyboard not having to fiddle with monitor menus is a godsend :)
The dongle that's having problems is a "Selore&S-Global USB-C HDMI + DP" if that's something you want to keep on file.
Thanks for the detailed response and all your work making the app possible!
All the app does is call a macOS function called IOAVServiceWriteI2C to send a standard DDC message to the monitor (something like “set brightness to 30”)
In your case, either the dongle or the monitor reacts unexpectedly to that message. What should happen is that the dongle should simply forward that message as it is to the monitor and the monitor should have firmware logic to interpret it correctly and either set the brightness to the sent value, or not do anything.
That’s why Apple will never implement native brightness changing using DDC.
They can’t risk having users come with problems like this one in the press, because the monitor or hub/dock does something funny with the DDC message and crashes.
Lunar can also function in software mode using gamma by following the instructions here: https://lunar.fyi/faq#bad-ddc
That mode will never crash a monitor because it doesn’t send any data to it.