The high-refresh teardown SIGSEGV was caused by ApplyMonitorsConfig disabling the
still-actively-captured high-refresh virtual output. Reorder teardown: Stop the screencast
FIRST (Mutter removes the virtual + auto-reverts the temporary config), then re-assert the
physical layout once the virtual is gone. Never reconfigure a live virtual CRTC.
With this, PUNKTFUNK_MUTTER_VIRTUAL_REFRESH=1 is stable: validated at 5120x1440@240 on
Mutter 50 + NVIDIA — virtual output Meta-0@240, real 240fps, gnome-shell survives back-to-back
sessions + teardowns, physical (HDMI-1) restored each time.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
enricobuehler
5f0306f073