Mac Studio Display Brightness Control Not Working
Apple Studio Display (2 monitors) connected to Mac Studio (2022) with Apple M1 Ultra chip running macOS Monterey (12.4).
After a power failure, one of the Mac Studio Display monitors is visibly dimmer than the other. Settings>Displays does not show any brightness adjustment for the dim monitor.
Troubleshooting: Restarting the system does not fix the issue. When checking the About This Mac> System Report> Graphics/Displays, the dim monitor fails to show the Display Firmware Version. The good monitor shows Display Firmware Version: Version 15.5 (Build 19F77).
Resolution: (1) Unplug both monitors and the Mac Studio computer for at least five or more minutes. (2) Next, plug in ONLY the dim display and let it start. There is no on/off switch on the monitors, so plugging in the monitor will cause it to start and go dark when done. Three dots will be visible for a short time in the middle of the screen as it starts. (3) Next, plug in the other monitor and the computer unit. Start all three devices. It appears this will force the system to recognize the correct firmware for the monitor (or force a firmware update).
This should resolve the issue. It happened to me twice in the last couple of months when power crashed (or my UPS tripped).
Studio Display