The "5-6 stale monitors that never tear down" failure (also seen with SudoVDA):
an orphan from a crashed/killed previous host lingers because the driver watchdog
is kept reset by a still-pinging new session, so it never fires for the orphan.
- Driver (pf-vdisplay control.rs): new IOCTL_CLEAR_ALL (0x804) -> tear down every
monitor. A pf-vdisplay extension; SudoVDA returns invalid for it (ignored), so
the host can issue it unconditionally.
- Host (vdisplay/sudovda.rs): send IOCTL_CLEAR_ALL once on startup (best-effort)
to reap orphans before creating ours; and surface a failing keepalive PING (the
old `let _ =` swallowed it, masking a lost control handle).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
enricobuehler
e27abc065e