INC-2026-06-25-002: P16g Complete Freeze on External Monitor Disconnect

Detected

2026-06-25 (total system freeze after disconnecting external monitor)

Mitigated

TBD

Resolved

TBD

Duration

Single occurrence — investigating

Severity

P2 (High) — Complete system lockup. No tty switch (Ctrl+Alt+F2), no SSH access, no network. Required hard power cycle (hold power button). All running applications and unsaved work lost.

Impact

After physically disconnecting an external monitor from the ThinkPad P16g, the entire system froze. No input method produced any response. The machine was unreachable over the network, ruling out a compositor-only hang. This is a kernel-level lockup, not a display-pipe issue like INC-2026-05-23-002.

Root Cause

TBD — likely NVIDIA DRM or i915 fault on monitor hot-unplug event. The i915.enable_psr=0 kernel parameter (applied for INC-2026-05-23-002) was already active, so PSR is not the cause. Suspect: DRM atomic commit deadlock during hot-unplug reconfiguration, possibly involving both i915 and nvidia-open in the hybrid GPU topology.

Machine

modestus-p16g.inside.domusdigitalis.dev (ThinkPad P16 Gen 1)

OS

Arch Linux

Kernel

7.0.12-arch1-1

Intel iGPU

Arrow Lake-S [Intel Graphics] (rev 06) — i915 driver

NVIDIA dGPU

NVIDIA GeForce RTX 5090 Laptop GPU (nvidia-open)

Compositor

Hyprland (Wayland)

Kernel parameters

nvidia_drm.modeset=1 mem_sleep_default=s2idle i915.enable_psr=0

Known display issues

WAYLAND-1 phantom headless output (unresolved), PSR hang (mitigated)

2026-06-25

External monitor connected to P16g via USB-C/Thunderbolt. System operating normally with dual displays.

2026-06-25

User physically disconnects external monitor cable.

2026-06-25

System freezes completely within seconds of disconnect. Screen frozen on last frame. No cursor movement, no keyboard response.

2026-06-25

Ctrl+Alt+F2 (tty switch) — no response.

2026-06-25

SSH from another machine — connection refused / unreachable. Network stack is dead.

2026-06-25

Hard power cycle (hold power button ~10s). System reboots cleanly.

2026-06-25

Incident report opened. Investigation pending — previous boot journal is the primary evidence source.

INC-2026-05-23-002

i915 PSR hang on idle — eDP-1 fails to wake from DPMS

Same machine, same hybrid GPU. Fix (i915.enable_psr=0) already applied — rules out PSR as cause.

INC-2026-05-23-001

Power button triggers shutdown instead of suspend

Same machine. Triggered during the PSR hang incident when user attempted to wake display.

WAYLAND-1

Phantom headless monitor output respawning

Same machine. Unknown source. May be related to DRM hot-unplug handling.

Incident ID

INC-2026-06-25-002

Author

Evan Rosado

Created

2026-06-25

Last Updated

2026-06-25

Status

Open (investigating)

Trigger

Physical disconnect of external monitor (USB-C/Thunderbolt)

Fix Location

TBD

Post-Incident Review

Pending