After a session ends, the Mutter backend (with PUNKTFUNK_MUTTER_VIRTUAL_PRIMARY=1)
re-asserted the physical monitor layout with an explicit ApplyMonitorsConfig. On
Mutter 50 + NVIDIA that monitor reconfig — issued while the just-removed high-refresh
virtual output is still tearing down — SIGSEGVs gnome-shell. Observed live on
home-worker-3: the teardown ApplyMonitorsConfig returns "recipient disconnected from
message bus" (the shell died mid-call), GDM's crash-loop guard then drops to the
greeter and STAYS there, so org.gnome.Mutter.RemoteDesktop/DisplayConfig vanish and
every subsequent reconnect fails with RemoteDesktop.CreateSession ServiceUnknown —
i.e. "after a disconnect I can't reconnect anymore."
make_virtual_primary applies an APPLY_TEMPORARY config, which Mutter reverts on its
own once the virtual output disappears and our DisplayConfig connection closes. So the
explicit restore was both redundant and the crash trigger: drop it, drop the dc_pre
connection at teardown, and let Mutter revert the temporary config itself. Setup is
unchanged (the virtual output is still made primary so the desktop lands on the
streamed surface). Removes the now-unused to_apply_logicals/apply_config helpers.
Verified live on home-worker-3 (5120x1440@240, VIRTUAL_PRIMARY=1): 6/6 back-to-back
connect/disconnect cycles streamed cleanly with gnome-shell holding the same PID
throughout (previously it crashed within the first few disconnects).
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
enricobuehler
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