u/sixtyfootersdude

Hardware:

• MacBook Pro (Mac17,2), Apple M5, 16 GB RAM
• macOS 26.2 (Build 25C56)
• Display Pilot 2 (latest version)

Display configuration:

• Built-in Liquid Retina XDR Display (3024×1964) — internal display
• BenQ MA320U (5120×2880, UI: 2560×1440) — primary/main external display
• Dell U2719D (1440×2560, portrait) — secondary external display

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Bug description:

When Display Pilot 2 puts the internal MacBook display to sleep, it causes two severe and unrecoverable side effects:

1. Internal display cannot be woken without a full session reset

After Display Pilot 2 sleeps the internal display, no standard macOS wake mechanism recovers it. Confirmed failed approaches include:

• Mouse/keyboard input
• caffeinate -u (user activity assertion)
• Writing IORequestIdle = false to IODisplayWrangler via IOKit (both as user and as root via sudo)
• Opening System Settings > Displays
• Closing and reopening the MacBook lid
• Force-quitting Display Pilot 2

The display remains stuck in Display Asleep: Yes state (confirmed via system_profiler SPDisplaysDataType and CGDisplayIsAsleep() via CoreGraphics) until a full system restart or WindowServer reset.

2. macOS menu bar disappears from all external displays

When the internal display is put to sleep by Display Pilot 2, macOS corrupts the display coordinate space for the BenQ (the main/primary display). The WindowServer Menubar window is repositioned to Y=-30, Height=30 — 30 pixels above the physical top edge of the BenQ display — making it completely invisible. This was confirmed by inspecting the window list via CGWindowListCopyWindowInfo.

The BenQ's visible display area starts at Y=0, so the menu bar is rendered entirely off-screen. The menu bar process (SystemUIServer) continues running normally — the issue is the window coordinates, not the process.

Attempted recovery steps that failed:

• killall SystemUIServer (restarts the menu bar process — menu bar reappears at same off-screen position)
• killall Dock
• Activating Finder to shift menu bar focus
• Swapping the main display assignment between BenQ and Dell and back (via CGBeginDisplayConfiguration / CGCompleteDisplayConfiguration)

Root cause hypothesis:

Display Pilot 2 appears to put the internal display to sleep using a private macOS API that sets a persistent display power state. When the internal display (which has a notch) goes to sleep while an external display is set as primary, macOS fails to recalculate the display coordinate geometry for the external display. The menu bar coordinate space retains an offset corresponding to the MacBook's notch geometry (30px), placing it above the visible area of the notch-free external display.

Steps to reproduce:

1. Connect a MacBook Pro (M-series, with notch) to one or more external displays
2. Set an external display as the primary/main display
3. Allow Display Pilot 2 to sleep the internal display (or trigger it manually)
4. Observe that the internal display cannot be woken and the menu bar vanishes from the primary external display

Recovery:

The only reliable recovery is:

sudo rm /Library/Preferences/com.apple.windowserver.displays.plist
sudo killall -KILL WindowServer

This deletes the persisted corrupted display layout and restarts the WindowServer, forcing macOS to rebuild the display configuration from scratch. A full system restart also works.

Expected behavior: Display Pilot 2 should either (a) not put the internal display into a sleep state that macOS cannot recover from without a session reset, or (b) restore the internal display to an active state when Display Pilot 2 is quit.

Impact: This issue requires a destructive session reset to recover from, causing loss of all open window positions and requiring applications to be relaunched. It has occurred repeatedly across multiple days of normal use.