Phase I: extends acpid with the full Linux 7.1 S-state AML
method sequence (\\_TTS / \\_PTS / \\_SI._SST / \\_WAK) plus
enter_s2idle / exit_s2idle methods for Modern Standby. The
FACS set_waking_vector / set_x_waking_vector methods prepare
the S3 resume path. Hardware-agnostic — the same AML
sequence applies to any platform with ACPI S3 or Modern
Standby (Dell, HP, Lenovo, LG Gram, etc.), not just LG Gram.
The kernel-side wire for s2idle is a follow-up. The current
commit does not add new AcpiVerb variants to the syscall
crate (that would require patching libredox too, which is
deferred to Phase J). Instead, s2idle coordination will go
through the existing kstop handle with new string args
('s2idle', 's3'), keeping the syscall crate ABI stable.
vasilito
4191b8543e