Power Management State (pmset) on the A2780
On the 16-inch M2 Max (A2780), deep sleep transitions (hibernatemode 3 / 25) invoke an intensive handshake between the Apple Silicon Secure Enclave Processor (SEP), the PMU, and the T-CON display controller.
When third-party USB-C hubs, external monitors, or low-voltage chargers interfere with the power rail handoff:
- The GPU enters low-power idle.
- The T-CON controller fails to receive the waking high-speed clock signal.
- The laptop appears "dead" with a black screen, even though SSH and AirDrop still work in the background!
Install DisplayGuard to enforce persistent display assertions (PreventUserIdleDisplaySleep).