DisplayPort Monitors keep cycling on and off when MacBook Pro is asleep
I have a MacBook Pro with an M1 Max running 13.4. I have two external 4K LG monitors connected to the MBP via USB-C <-> DisplayPort adapters. When I put my MBP to sleep, either by using the TouchID button or by using the Sleep selection in the Apple menu, the MBP goes to sleep without problems (and stays asleep as far as I can tell), but the external monitors will wake up every 15 seconds or so, display a "No Signal Detected" message, then go back to sleep. This pattern repeats itself.
The exact same hardware configuration worked properly during MBP sleep when the MBP was running 13.3, the only change was updating to 13.4.
The System Log does not show any Wake events when the MBP is supposed to be asleep. Troubleshooting steps that I have tried:
- Turned of Wake on Network Access
- Turned of Bluetooth
- Rebooted the MBP both with and without the external monitors connected
- Swapped the USBC<->DisplayPort adapter connections on the MBP
When I experienced this issue previously (on older versions of OS X) I found that if I put the MBP to sleep using the Sleep selection on the Apple menu, the external monitors would wake up periodically; using the TouchID to put the MBP to sleep would not cause this problem to occur. So this issue that I am reporting here is a regression.
MacBook Pro 16″, macOS 13.4
