Phase II.X.W: extend the AcpiVerb enum with two new variants
for the S3 round-trip:
* AcpiVerb::SetS3WakingVector (= 5): acpid writes the
kernel's S3 resume trampoline address to FACS.
Mirrors Linux 7.1's acpi_set_firmware_waking_vector.
The 8-byte write payload is the address in
little-endian. A zero payload is a sentinel for 'use the
kernel's default trampoline address' (s3_trampoline
symbol).
* AcpiVerb::EnterS3 (= 6): acpid requests the kernel to
enter S3. The kernel's stop::enter_s3() reads the
SLP_TYP value from S3_SLP_TYP and does the PM1 register
write. The actual S3 entry happens via acpid writing
to /scheme/sys/kstop.
Hardware-agnostic: works on any x86_64 system with
standard ACPI S3 support (Dell, HP, Lenovo, LG Gram 14).
On Modern Standby-only systems (LG Gram 16 (2025)), the
kernel never enters S3 so these verbs are no-ops.
Phase I/J: hardware-agnostic s2idle / Modern Standby
support. These AcpiVerb variants are needed on any
platform with Modern Standby firmware (Dell, HP, Lenovo,
LG Gram, etc.), not just LG Gram. They mirror Linux 7.1:
* EnterS2Idle (= 3) — s2idle_enter() in
kernel/power/suspend.c:91
* ExitS2Idle (= 4) — s2idle_wake() in
kernel/power/suspend.c:133
The version field stays at upstream 0.8.1. We do NOT
bump the version — this is the durable overlay pattern
(per AGENTS.md 'GOLDEN RULE — Red Bear adapts to
upstream, never the reverse'). Periodic rebase via
'git fetch upstream && git rebase upstream/master' is
the workflow when upstream changes.
The patch file backing this commit is at
local/patches/syscall/P1-acpiverb-enter-exit-s2idle.patch
in the outer RedBear-OS repo.
* The original argument `is_parent_sigchld` was misleading as it
applied to any `SIGCHLD` sent to the parent (exit and stop/continue).
`SA_NOCLDSTOP` should only suppress stop and continue events, not
exits.
* Document the behaviour.
Signed-off-by: Anhad Singh <andypython@protonmail.com>
vasilito
Ibuki Omatsu