Round 2 follow-up to lid-closed → enter_s2idle wiring. Without
the symmetric lid-open → exit_s2idle call, the system stays in
'wake devices armed' state after the lid opens (until the kernel
kstop reason=2 path fires, which only happens if MWAIT actually
engaged).
Lid-open now runs the AML wake sequence (_SST(2) → _WAK(0) →
_SST(1) + wake-device disarming). The kernel-side MWAIT-return
path also calls exit_s2idle(); the double-call is safe because
AML _WAK/_SST methods are spec-required to be idempotent in the
working state (ACPI 6.5 §3.5.3).
External-display detection (Linux's HandleLidSwitchDocked=ignore)
is still not wired — every lid-close triggers s2idle. Documented
as a follow-up in the LG Gram assessment doc.
Red Bear OS
887718da49