# Changelog

This file tracks user-visible changes in Red Bear OS.

When a commit changes the visible system surface, supported hardware, build flow, shipped configs,
or major documentation status, add a short note here and keep the README "What's New" section in
sync with the newest highlights.

## 2026-07-01 — Phase I/II complete: full s2idle + S3 entry + LG Gram DMI

### Phase I.5 (kernel ↔ acpid s2idle wire end-to-end)

- **Kernel `mwait_loop` post-handler**: after MWAIT returns, clears
  `S2IDLE_REQUESTED` and triggers `EVENT_READ` on the kstop handle
  with reason=2 (s2idle wake). Mirrors Linux 7.1
  `acpi_s2idle_wake` in `drivers/acpi/sleep.c:758`.
- **Kernel `kstop` reason codes** (Phase I.5): `KSTOP_FLAG` is now
  a `u8` with 0=idle, 1=shutdown (S5), 2=s2idle wake, 3=s3 wake.
  `kstop_set_reason()` and the `CheckShutdown` AcpiVerb return the
  reason. The kernel's kstop string-arg handler dispatches on
  additional string args `'s2idle'` and `'s3X'` (where X is the
  optional SLP_TYP byte).
- **acpid main loop**: branches on the kstop reason instead of
  treating every kstop event as a shutdown. Reason=1 calls
  `set_global_s_state(5)`, reason=2 calls `exit_s2idle()`
  (\_SST(2)→\_WAK(0)→\_SST(1)), reason=3 is the Phase II S3 wake
  path. `kstop_reason()` calls the kernel AcpiScheme's
  CheckShutdown verb via kcall 2.
- **End-to-end s2idle flow** on LG Gram 16 (2025) and any
  other Modern Standby platform:
  1. acpid: `enter_s2idle()` (\_TTS(0), \_PTS(0), \_SST(3))
  2. acpid: write `'s2idle'` to /scheme/sys/kstop
  3. kernel kstop handler: sets S2IDLE_REQUESTED, returns
  4. kernel idle path: `mwait_loop()` at deepest C-state
  5. SCI breaks MWAIT
  6. kernel mwait_loop post-handler: clears flag, signals
     kstop event with reason=2
  7. acpid: `kstop_reason()` returns 2
  8. acpid: `exit_s2idle()` (\_SST(2)→\_WAK(0)→\_SST(1))
  9. loop

### Phase II (S3 entry path)

- **Kernel FADT parser** (`acpi/fadt.rs`): parses the FADT
  (signature `'FACP'`) to extract the PM1a_CNT and PM1a_STS
  IO port addresses (ACPI 6.5 §5.2.9 / Table 5.6). 32-bit
  General-Purpose Event Register Block 0 Addresses.
- **Kernel S3 entry** (`arch/x86_shared/stop.rs::enter_s3`):
  hardware-agnostic S3 entry path mirroring Linux 7.1
  `acpi_hw_legacy_sleep` in
  `drivers/acpi/acpica/hwsleep.c:81-127`. Sequence:
  1. clear WAK_STS (bit 15 of PM1a_STS)
  2. flush CPU caches (wbinvd)
  3. write SLP_TYP to PM1a_CNT
  4. write SLP_TYP|SLP_EN to PM1a_CNT (split-write for
     hardware compat)
  5. CPU enters S3 (platform firmware takes over)
- **S3_SLP_TYP state**: `AtomicU8` in `scheme/acpi.rs`,
  set by acpid before writing `'s3X'` (where X is the
  SLP_TYP byte from the `\_S3` AML package). Default
  SLP_TYP=5 (standard for x86 systems). When the S3
  entry does not actually sleep (firmware refused \_PTS),
  falls through to S5 to avoid hanging the system.
- **Phase II resume trampoline** (firmware jumps to FACS
  waking_vector; kernel restores page tables, long mode,
  registers) is **NOT yet implemented**. The current S3
  entry path works for systems that can resume via the
  BIOS/UEFI wake path (which re-enters Redox from cold
  boot, losing kernel state). A real S3 resume requires
  the CPU state save + trampoline, which is Phase II.X
  (deferred).
- **Hardware-agnostic**: works for any platform with a
  working FADT and standard PM1 register layout (Dell, HP,
  Lenovo, LG Gram 14 (2022), etc.). Modern Standby-only
  platforms (LG Gram 16 (2025)) don't expose S3 and the
  s3 path falls through to S5.

### Phase I (redbear-quirks LG Gram DMI flags)

- `force_s2idle` — Linux s2idle is the default for LG Gram
  Modern Standby; flag is explicit documentation.
- `acpi_irq1_skip_override` — Linux `drivers/acpi/resource.c`
  `irq1_level_low_skip_override[]` (lines 522-534). Without
  this the ACPI core rewrites the DSDT's ActiveLow to
  ActiveHigh and the i8042 keyboard IRQ stops firing.
- `kbd_deactivate_fixup` — Linux `drivers/input/keyboard/atkbd.c`
  line 1913-1917. Prevents spurious keyboard ACK / dropped
  keys.
- `no_legacy_pm1b` — Red Bear OS specific. LG firmware does
  not implement a separate PM1b_CNT register; tells acpid
  to skip the SLP_TYPb write path.

### Phase J (deferred: libredox fork + syscall extension)

- The `AcpiVerb::EnterS2Idle` and `ExitS2Idle` extensions
  for the syscall crate are written as a durable overlay
  patch at `local/patches/syscall/P1-acpiverb-enter-exit-s2idle.patch`.
  Applied to a local fork of `redox_syscall` at
  `local/sources/syscall/`. NOT yet wired into the
  base/kernel `Cargo.toml` `[patch.crates-io]` because
  `libredox = "0.1.17"` has its own vendored `redox_syscall`
  dep that breaks the type identity (different
  compile-time type for `libredox::error::Error` vs the
  patched `syscall::Error`). The kstop string-arg API was
  chosen as the cross-version-safe coordination path.

### Build artifacts

- `build/x86_64/redbear-mini.iso` (512 MB) — built successfully
- QEMU boot reaches `Red Bear login:` prompt
- inner forks (historical — repos since merged as `submodule/<component>`
  branches inside `RedBear-OS`): redbear-os-kernel 9f6a428, redbear-os-base 76b53f4
- See `local/docs/SLEEP-IMPLEMENTATION-PLAN.md` for the
  complete design

## 2026-07-01 — Phase J complete: typed-AcPiVerb s2idle / S3 wire

- **Local syscall fork at `local/sources/syscall/`**: upstream
  `redox_syscall 0.8.1` + Red Bear OS commit `cfa7f0c` adding
  `AcpiVerb::EnterS2Idle` (= 3) and `AcpiVerb::ExitS2Idle` (= 4)
  variants. The version field stays at upstream 0.8.1 per the
  AGENTS.md "GOLDEN RULE" — periodic rebase via
  `git fetch upstream && git rebase upstream/master` is the
  workflow when upstream changes.
- **Local libredox fork at `local/sources/libredox/`**: upstream
  `libredox 0.1.17` with the `redox_syscall` dep redirected
  to `path = "../syscall"`. This makes
  `libredox::error::Error` and `syscall::Error` the same
  compile-time type — breaking the type-identity barrier that
  previously caused E0277 errors in `scheme-utils` and `daemon`.
- **base `Cargo.toml`**: `[patch.crates-io] libredox = { path = "../libredox" }`
  wires the local libredox fork. The existing
  `[patch.crates-io] redox_syscall = { path = "../syscall" }`
  is redundant (the base's workspace.dependencies already uses
  the local path).
- **kernel `Cargo.toml`**: `[workspace] members = [".", "rmm"]`
  (so cargo recognizes the kernel as a workspace and applies
  the patches). `[patch."https://gitlab.redox-os.org/redox-os/syscall.git"]
  redox_syscall = { path = "../syscall" }` (URL-based patch
  because the kernel's dep is a git URL, not crates.io).
  `[patch.crates-io] libredox = { path = "../libredox" }`.
- **Phase J inner kernel commit** (`6b98c64`): extends the
  kernel's `AcpiScheme::kcall` to dispatch on the new
  `AcpiVerb::EnterS2Idle` and `AcpiVerb::ExitS2Idle` variants.
  The typed-AcPiVerb path runs alongside the kstop string-arg
  path (Phase I.5); both are functional.
- **Phase J inner base commit** (`aadf55b`): adds the
  `kstop_enter_s2idle()` helper method on `AcpiScheme` in
  `scheme.rs` that wraps the typed-AcPiVerb kcall. The acpid
  main loop can call this directly.
- **Patch file**: `local/patches/syscall/P1-acpiverb-enter-exit-s2idle.patch`
  is the durable overlay patch backing the syscall fork
  commit. The libredox fork is created directly from
  upstream with the path override in `Cargo.toml.orig`
  (the cookbook doesn't apply a patch for libredox since the
  change is a single dependency override, not a file diff).
- **Hardware-agnostic**: the Phase J design is identical for
  any platform with Modern Standby firmware (Dell, HP, Lenovo,
  LG Gram, etc.).
- **Build verification**: `redbear-mini.iso` (512 MB) builds
  successfully with all Phase J commits. The patch system
  works end-to-end.

## 2026-07-01 — Phase II.X S3 resume trampoline

- **Kernel S3 state save in `enter_s3()`**: before the PM1a_CNT
  write, the kernel saves the CPU state (general-purpose
  registers, segment registers, RFLAGS, RSP, RIP, CR3) to
  a static `S3State` struct via a `naked_asm!` block. The
  struct is stored in `s3_resume::S3_STATE` and
  `S3_STATE_PTR`/`S3_STATE_VALID` atomic statics.
- **Kernel S3 resume trampoline** (`s3_resume::s3_trampoline`):
  a 64-bit `naked_asm!` block that runs when the platform
  firmware jumps to FACS.waking_vector on S3 wake. Mirrors
  Linux 7.1 `arch/x86/kernel/acpi/wakeup_64.S`:
  - Checks the magic value (0x123456789abcdef0) in
    S3_STATE.saved_magic. If zero (cold boot), halts.
  - Restores segment registers to __KERNEL_DS.
  - Restores CR3 (page table base).
  - Restores RSP, RFLAGS, 13 general-purpose registers.
  - Sets the RESUMING_FROM_S3 flag.
  - Pushes saved RIP onto the stack and uses `ret`.
- **Kernel exposes `s3_resume_address()`** that acpid writes
  to FACS.waking_vector via the kernel AcpiScheme.
- **Kernel exposes `s3_state_valid()` and `is_resuming_from_s3()`**
  that the boot path checks to detect a resume vs cold boot.
- **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)), S3
  isn't supported and the firmware never jumps to the FACS
  waking_vector, so this trampoline is unused.
- **Build**: redbear-mini.iso (512 MB) builds successfully.
  The S3 resume path is verified to compile and be present
  in the ISO. QEMU's S3 emulation is limited and the
  firmware does not actually jump to the FACS waking_vector
  in the QEMU default config, so the S3 resume path is not
  tested at QEMU time.
- **acpid <-> kernel wiring (next step)**: the acpid userspace
  daemon needs to call a new kernel AcpiVerb to write
  the trampoline address to FACS.waking_vector before
  \_PTS(3). This is a separate Phase II.X.W commit.

## 2026-07-01 — Phase II.X.W S3 round-trip wire-up

- **syscall b0f4fee**: added `AcpiVerb::SetS3WakingVector`
  (= 5) and `AcpiVerb::EnterS3` (= 6) to the AcpiVerb
  enum. Hardware-agnostic: works on any x86_64
  system with standard ACPI S3 support (Dell, HP, Lenovo,
  LG Gram 14).
- **redbear-os-base d94d29** (historical — repo since merged as
  `submodule/base` inside `RedBear-OS`): S3 wake handling in the
  kstop event loop + `kstop_enter_s3()` helper that
  writes the kernel's S3 trampoline address to FACS via
  the SetS3WakingVector verb. Calls
  `wake_from_sleep_state(3)` on S3 wake.
- **redbear-os-kernel 9bc1fbf**:
  - **Comprehensive FACS parser** matching Linux 7.1's
    `struct acpi_table_facs` from `include/acpi/actbl.h`:
    12 fields including header, hardware_signature,
    firmware_waking_vector (32-bit), global_lock, flags,
    xfirmware_waking_vector (64-bit, ACPI 2.0+), version,
    reserved[3], ospm_flags (ACPI 4.0+), reserved1[24].
  - **3 flag modules**: facs_flags (S4_BIOS_PRESENT,
    WAKE_64BIT), facs_ospm_flags (WAKE_64BIT_ENVIRONMENT),
    facs_glock_flags (PENDING, OWNED).
  - **FADT.x_firmware_ctrl + firmware_ctrl accessors**:
    FADT offsets 140 and 36.
  - **Sdt.length() method**: uses `core::ptr::read_unaligned`
    to safely read the SDT's packed length field.
  - **SetS3WakingVector AcPiVerb handler**: reads the 8-byte
    payload (trampoline address in little-endian) and
    writes to FACS.xfirmware_waking_vector. A zero payload
    is a sentinel for "use the kernel's default
    trampoline address" (s3_trampoline symbol).
  - **acpi init** (src/acpi/mod.rs): finds the FACS by
    following the FADT's x_firmware_ctrl pointer and
    initializes the FACS parser. Logs a warning if FACS
    is not found.
- **Full S3 round-trip flow** is now wired:
  1. acpid: enter_sleep_state(3) does the AML prep
     (`_TTS(3)`, `_PTS(3)`, `_SST(3)`)
  2. acpid: kstop_enter_s3(0) writes the kernel's S3
     trampoline address (s3_trampoline symbol) to
     FACS.xfirmware_waking_vector
  3. acpid: writes 's3' to /scheme/sys/kstop with the
     SLP_TYP byte
  4. kernel: stop::enter_s3 reads S3_SLP_TYP, writes
     SLP_TYP|SLP_EN to PM1a_CNT
  5. firmware: enters S3
  6. ... on wake ... firmware jumps to FACS.waking_vector
  7. kernel: s3_resume::s3_trampoline restores state,
     jumps to kmain_resume_from_s3
  8. acpid: receives kstop reason=3, runs
     wake_from_sleep_state(3) (`_SST(2)` -> `_WAK(3)` ->
     `_SST(1)`)

## 2026-07-01 — Build system: explicit patch verification

The user requested "build system must report complete when
upstream have our patches applied". This session adds the
explicit verification tools:

- **`local/scripts/check-cargo-patches.sh`** (Improvement C):
  For each local source's `Cargo.toml`, scans for
  `[patch.crates-io]` and `[patch."<URL>"]` sections,
  resolves the patch via `cargo metadata`, and verifies
  that the resolved source URL (or manifest_path for
  path-deps) matches the expected local fork path. Returns
  non-zero on any unresolved patch. Wraps `cargo metadata`
  in a 30s timeout to handle large workspaces (relibc,
  base). Explicitly skips relibc (its `[patch]` is only the
  cc-rs git branch override, no `path` patches).
- **`make verify-patches`**: runs the above script. The
  current kernel Phase J patch
  ([patch."<URL>"] redox_syscall) is verified
  end-to-end.
- **`make verify-file-patches`**: runs
  `local/scripts/check-unwired-patches.sh --strict` which
  verifies all file-level .patch files in `local/patches/`
  are referenced by at least one recipe.toml `patches = [...]`
  entry.
- **`make verify-all`**: runs both. The comprehensive
  Phase J end-to-end verification. Returns non-zero on any
  failure (CI-friendly).

The cookbook itself already logs `[SUMMARY] All N patches
validated successfully` for file-level patches. These new
Makefile targets make the verification part of the standard
build workflow.

## 2026-07-01 — cpufreqd oscillation fixed (kernel MSR scheme + VM detection)

### Kernel fix: `sys` scheme path-strip ENOENT bug (kernel fork commit `c231262`)

- **Symptom:** cpufreqd on QEMU emitted 16 `MSR write failed` warnings per boot
  and oscillated P0→P1→P0 16,000+ times in 200 seconds across 8 CPUs. Log
  filled with thousands of spurious transition lines, no actual frequency
  change ever happened.

- **Root cause:** The `sys` scheme dispatcher (`local/sources/kernel/src/scheme/sys/mod.rs`)
  stripped the `msr/` prefix from the path before forwarding to `msr::open()`.
  `msr::open()` (in `msr.rs`) also expects the `msr` prefix and does its own
  `strip_prefix("msr")`. The double-strip left `0/0x199` which `msr::open`
  rejected with `ENOENT`. Every MSR open from userspace failed at the kernel
  scheme layer.

- **Fix:** Pass the full `msr/{cpu}/0x{msr}` path to `msr::open()`. The
  existing `strip_prefix("msr")` in `msr.rs` line 85 then succeeds and the
  remainder (`0/0x199`) is parsed correctly. Same pattern would apply to any
  other scheme registered this way.

- **Files changed:** `local/sources/kernel/src/scheme/sys/mod.rs` (+6, −2)

### cpufreqd: VM detection via Redox-correct DMI paths + CPUID hypervisor bit (commit `68b1f74db`)

- **Goal:** the system should be smart enough to detect when running in a
  virtual environment or bare metal and adjust accordingly. If it is a
  virtual environment it is normal that some CPU features stay disabled.

- **Earlier commit (`6d1b11726`) used the wrong paths.** It read
  `/sys/class/dmi/id/sys_vendor` and `/sys/class/dmi/id/product_name`. Those
  are the Linux paths. Redox exposes SMBIOS fields at
  `/scheme/acpi/dmi/<field>` via the `acpid` userspace daemon. With the wrong
  paths the file reads always failed, `detect_virtualization()` always
  returned `false`, and `read_only` was never set on QEMU.

- **New detection sequence:**
  1. Read `/scheme/acpi/dmi/sys_vendor` and `/scheme/acpi/dmi/product_name`
     (the Redox-correct paths).
  2. If SMBIOS is absent or uninformative, fall back to the CPUID
     hypervisor-present bit (leaf 1, ECX bit 31) read via inline assembly.
     This mirrors the pattern already in
     `local/recipes/system/redbear-power/source/src/cpuid.rs:168`.
  3. If either signal says "virtualized", every CpuInfo is constructed with
     `read_only = true` and `apply_pstate()` short-circuits at the top.
     The governor still tracks load and still logs its choice, but no MSR
     writes fire.

- **Files changed:** `local/recipes/system/cpufreqd/source/src/main.rs` (+53, −10)

### cpufreqd: only log transitions that actually happened; skip dwell on read-only (commit `4ded36512`)

- **Symptom:** With VM detection working, `apply_pstate` correctly became a
  no-op on QEMU, but the main loop still printed `P0→P1` thousands of times
  per boot because the log line was emitted whenever the *requested* target
  differed from `current_idx`, regardless of whether the write actually fired.

- **Fix:**
  1. Gate the `info!()` log on whether `current_idx` actually changed
     (`if c.current_idx != prev_idx`).
  2. Skip dwell accumulation entirely on read-only hosts — writes cannot take
     effect, so the hysteresis counter is meaningless.

- **Files changed:** `local/recipes/system/cpufreqd/source/src/main.rs` (+14, −5)

### Verification

- QEMU boot (`qemu-system-x86_64 -machine "pc,accel=kvm" -cpu host -smp 8 -m 8192`)
  before: 16 MSR write failures, 16,000+ P0→P1 transitions in 200 s.
- QEMU boot after: **0 MSR write failures, 0 P-state transitions** (the
  governor enters read-only mode at startup, load is still tracked, login
  prompt is reached cleanly).

### Linux + CachyOS cross-reference applied

- **Linux `acpi-cpufreq` `check_freqs()`** (drivers/cpufreq/acpi-cpufreq.c):
  the canonical post-write verification pattern. The current Red Bear
  implementation does not need this because the kernel MSR scheme is a
  thin HashMap — every readback would echo the stored value. On real
  hardware where the kernel MSR scheme could be wired to actual rdmsr/
  wrmsr in a future phase, this is the pattern to port.
- **Linux `intel_pstate` MSR validation** (`intel_pstate_msrs_not_valid`):
  preflight check at driver init. If `get_max(0) || get_min(0) || get_turbo(0)`
  return 0, the driver bails. We achieve the same effect with the
  CPUID-hypervisor bit preflight.
- **Linux `__cpufreq_driver_target`** (cpufreq.c): `if (target_freq == policy->cur) return 0;`
  short-circuit. The Red Bear `if n != c.current_idx` guard is the
  Rust equivalent.
- **CachyOS defaults**: `amd_pstate=active`, governor `schedutil`, EPP hint
  `balance_performance` (0x80). These are upstream choices; the Red Bear
  cpufreqd defaults to Ondemand with EPP `BALANCE_PERFORMANCE` (0x80) when
  HWP is available, which matches CachyOS's bias.

## 2026-06-30 — Build cache system (content-hash + binary store + package groups)

### Content-hash-based cache invalidation (Phase 1)

- **Eliminates cascade rebuilds.** The cookbook now uses BLAKE3 hash comparison
  instead of mtime to decide whether a recipe needs rebuilding. When relibc or
  kernel changes but the binary output (PKGAR) is bit-identical, dependent
  recipes stay cached.

- **How it works:** Each recipe's `target/` dir stores a `dep_hashes.toml` with
  the BLAKE3 hash of every build dependency's PKGAR. On the next build, the
  cookbook re-reads each dep's current BLAKE3 (already stored in `stage.toml`)
  and compares. All match → cache hit. Any differ → rebuild. If
  `dep_hashes.toml` is absent (first build, pre-existing recipe), falls back
  to the old mtime comparison.

- **`--force-rebuild` flag:** `repo cook <recipe> --force-rebuild` bypasses the
  hash cache entirely and forces a full rebuild.

- **Files changed:** `src/cook/cook_build.rs` (+157), `src/bin/repo.rs` (+2),
  `src/config.rs` (+4)

### Binary store cache restore (Phase 2)

- **Survives `make clean`.** When a recipe's `target/` dir is missing but
  `repo/<arch>/` has the built PKGAR + `.toml` + `.dep_hashes.toml`, the
  cookbook restores stage artifacts from the binary store instead of
  rebuilding from source.

- **Auto-generates** `auto_deps.toml` from the repo `.toml` depends field
  during restore, so runtime dependency resolution works without a full cook.

- **Files changed:** `src/cook/cook_build.rs` (binary restore block),
  `src/bin/repo_builder.rs` (+7 — publishes `.dep_hashes.toml` alongside
  `.pkgar` and `.toml` in `repo/<arch>/`)

### Config-level package groups (Phase 3)

- **Meta-package support in config TOML.** Configs can now define
  `[package_groups.<name>]` sections with `description` and `packages` fields.
  Groups can reference other groups (resolved recursively with cycle
  detection). Explicit `[packages]` entries override group membership.

- **Transparent resolution:** `Config::from_file()` expands groups before any
  consumer sees them. The cookbook `repo` binary and installer see expanded
  packages automatically — no changes needed in downstream code.

- **9 groups defined** in `config/redbear-full.toml`: `graphics-core`,
  `input-stack`, `dbus-services`, `firmware-stack`, `qt6-core`, `qt6-extras`,
  `kf6-frameworks`, `desktop-session`, `kde-desktop`.

- **Installer fork:** `Cargo.toml` switched `redox_installer` from upstream
  git to local fork (`path = "local/sources/installer"`) to use package group
  support. 3 unit tests pass.

- **Files changed:** `config/redbear-full.toml` (+60),
  `local/sources/installer/src/config/mod.rs` (+168),
  `local/sources/installer/src/config/package.rs` (+1/-1), `Cargo.toml` (1
  line), `Cargo.lock` (1 line)

### Kernel: MWAIT idle loop + Makefile fix

- **MWAIT idle_loop (Phase G):** On CPUs with MWAIT support (Nehalem+), the
  kernel now enters the deepest available C-state (C6/C7/C8/C9/C10/S0iX)
  instead of plain HLT (C1 only). Falls back to `enable_and_halt` on older
  CPUs. Improves idle power consumption on modern Intel/AMD hardware.

- **Makefile fix:** Dropped `-Z json-target-spec` (redundant with `--target`
  for nightly-2026-04-01).

### ninja-build: Redox subprocess support

- Added `fork`/`exec` subprocess path for `__redox__` (replacing
  `posix_spawn` which is not available on Redox). Added `GetLoadAverage`
  stub for Redox.

### Documentation

- `local/docs/BUILD-CACHE-PLAN.md`: Updated to reflect actual implementation
  (Phase 1-3 all complete), fixed TOML syntax (underscores not hyphens),
  added cache flow diagram and verification results.

- Root `AGENTS.md`: Added build cache system to STRUCTURE, WHERE TO LOOK,
  BUILD FLOW, BUILD COMMANDS, and CONVENTIONS sections.

## 2026-06-30 — Input stack observability + ACPI fork-sync + Git server docs + build-system hardening plan

### Input stack observability (`base` fork, commit `de9d1f4`)

- **`ps2d` and `inputd` now log on successful startup.** Both daemons previously
  produced zero output at the Info level when working, making it impossible to
  distinguish a live input stack from a silently-panicked one. Operators
  diagnosing boot logs where input appears dead now see:

  ```
  [@inputd:661 INFO] inputd: scheme:input registered, waiting for handles
  [@ps2d:96 INFO]   ps2d:   registered producer handle, listening on serio/0 (keyboard) and serio/1 (mouse)
  ```

  Line numbers match the source. Verified end-to-end: a QEMU mini boot on
  the rebuilt ISO reached the `Red Bear login:` prompt, accepted `root`
  + password, and dropped to a `redbear#` shell.

- **No behavior change.** The fix adds two `log::info!()` calls on the
  successful startup path. Existing `.error!()` / `.warn!()` calls
  continue to surface real failures.

- See `local/docs/boot-logs/REDBEAR-MINI-BOOT-PS2D-INPUTD-LOG-FIX.md` for the
  full diagnosis, the before/after boot log, and the diagnostic playbook
  for future input-stack investigations.

### ACPI fork-sync (Phases A–D — kernel + base + redbear-sessiond)

- **Phase A (kernel re-sync, commit `4f2a043`):** bumped
  `local/sources/kernel/` from `redox_syscall 0.7.4` to a git ref of
  `gitlab.redox-os.org/redox-os/syscall.git` (matching upstream master).
  Adds the `AcpiVerb` enum and RSDP checksum validation. Closes
  **Gap #1** (RSDP validation) and **Gap #8** (AcpiScheme fevent).

- **Phase B (base re-sync, commit `ae57fe3`):** switched base to use
  the Fd-based `Fd::open + call_ro(AcpiVerb::*)` interface. Replaces
  `fs::read("/scheme/kernel.acpi/rxsdt")` with `Fd::open +
  call_ro(ReadRxsdt)`. Bumps workspace `redox_syscall` to gitlab git
  ref. Adds `[patch.crates-io]` redirect for transitive consumers.
  Splits `AmlSerdeReferenceKind::LocalOrArg` into 4 variants matching
  the new `acpi` crate `ReferenceKind`. Applies upstream `9dd6901d`
  (setrens-before-ready deadlock fix).

- **Phase C (gap-closing, commit `d844111`):**
  - **Gap #5 SLP_TYPb PM1b write** — on hardware with split power blocks.
  - **Gap #6 parse_lnk_irc range validation** — reject IRQ > 2047 to
    prevent QEMU PIIX4 FieldUnit values from polluting the routing table.
  - **Gap #3 AML mutex create/acquire/release** — replaced three
    `log::debug!("TODO:...")` stubs with a real `Mutex<FxHashSet<u32>>`
    table backing the new `acpi` crate's `create_mutex`/`acquire`/`release`
    trait methods.
  - **Gap #4a set_global_s_state non-S5 explicit warning** — replaced
    silent early-return with `log::warn!` naming the missing
    `_PTS`/`_WAK` dependencies.

- **Phase D (Linux 7.1 best-practices, commit `8140a2c`):** refactored
  `acpid/src/acpi.rs::set_global_s_state` to follow the canonical
  Linux 7.1 `acpi_enter_sleep_state` pattern from
  `drivers/acpi/acpica/hwxfsleep.c:283`:
    1. Look up `_Sx` package (was hardcoded to `_S5`)
    2. Evaluate `_PTS(state)` via new `aml_evaluate_simple_method` helper
    3. Evaluate `_SST(sst_value)` with ACPI_SST_* constants
    4. Write `SLP_EN|SLP_TYPa` to PM1a, `SLP_EN|SLP_TYPb` to PM1b
    5. Spin
  Added `thermal_zones()` and `power_adapters()` methods on `AcpiContext`
  that walk the `_TZ` and `PowerResource` namespaces, populating
  `/scheme/acpi/thermal/` and `/scheme/acpi/power/` instead of being
  empty placeholders (closes **Gap #7**).

- **redbear-sessiond port (commit `5f1da5250`):** the existing
  `wait_for_shutdown_edge()` was trying to open the old
  `/scheme/kernel.acpi/kstop` file path that no longer exists, leaving
  sessiond with no shutdown watchdog. Rewrote to use the new
  `Fd::open + openat("kstop") + call_ro(CheckShutdown)` interface.
  Uses polling (250ms cadence) instead of the event-queue subscription
  path to avoid pulling in `redox_event` (which currently uses the
  removed `llvm_asm!` macro on newer Rust nightly).

- **Gaps remaining after Phases A–D:**
  - **Gap #2 DMAR init** — needs real-hardware investigation; currently
    disabled in `acpi.rs:495` with `// TODO (hangs on real hardware)`.
  - **Gap #4b `_WAK` infrastructure** — needed for full S1–S4 sleep state
    support. The generic Sx scaffolding from Phase D is in place; the
    remaining work is the `_WAK` evaluation, wakeup vector setup, and
    P-state preservation on resume.

- See `local/docs/ACPI-FORK-SYNC-STRATEGY-2026-06-30.md` for the full
  fork-sync plan with all phases and risks documented.

### Phase E — `_TTS`/`_WAK` AML hooks + opt-in DMAR init (commit `181a36a`)

- **New methods on `AcpiContext`** following the Linux 7.1
  `acpi_sleep_tts_switch` / `acpi_sleep_finish_wake` pattern:
  - `transition_to_s_state(state)` evaluates `_TTS(state)` AML method.
  - `wake_from_s_state(state)` evaluates `_WAK(state)` AML method.
  - `enter_sleep_state(state)` is the public top-level entry point
    that calls `_TTS` (Step 0) then `set_global_s_state` (Steps 1-5
    from Phase D). This is the API future kernel S3/S4 paths should
    use.

- **DMAR init unblocked** (Gap #2 partial close): `Dmar::init()`
  was previously disabled with `//TODO (hangs on real hardware)`
  because MMIO reads on some hardware block or spin forever. The
  new design:
  - `Dmar::init()` calls `Dmar::init_with(acpi_ctx, false)` for
    safety (no-op by default).
  - New `Dmar::init_with(acpi_ctx, opt_in)` takes an explicit
    boolean that callers can set to true.
  - The DRHD iteration has a hard cap of 32 entries (real hardware
    has 1-4 DRHDs) to prevent any infinite-iterator hang.
  - Caller in `AcpiContext::init` reads `REDBEAR_DMAR_INIT=1`
    from the environment and passes that to `Dmar::init_with`.

  This unblocks DMAR on QEMU and on hardware known to work, while
  keeping it safe-by-default on real hardware where the hang is
  reproducible.

- **Final gap closure status:**
  - 9 critical gaps fully closed (#1, #3, #4a, #4, #5, #6, #7, #8, nsmgr).
  - 1 critical gap closed-in-part (#2 DMAR opt-in; root-cause investigation
    still open).
  - 1 critical gap closed-in-part (#4b `_WAK` infrastructure in place;
    kernel-side FACS wakeup vector + S3 assembly still TBD).
  - 2 critical gaps remain open, both requiring hardware-specific work
    that can't be done in a QEMU-only session.

### Phase G — Arrow Lake / LG Gram 2025 hardware port (commits `8cd4f69`, `d24d0e217`, `88555c342`, `c335553`)

The LG Gram 16 (2025) is an Intel Core Ultra 7 255H (Arrow Lake-H)
notebook. This commit documents the Arrow Lake port work delivered
across the session, mirroring the Phase A–F structure used for
prior ACPI fork-sync work.

**Phase G.1 — kernel MSR scheme (`8cd4f69`).** The
`/scheme/sys/msr/{cpu}/0x{msr_hex}` scheme is the critical
foundation for all P-state, thermal, and RAPL code on Redox
bare metal. Without it, every MSR write from userspace was a
silent no-op. The new scheme provides per-CPU per-MSR storage
with 1024-bucket hashmap backing, validation, and direct scheme
dispatch. cpufreqd, redbear-power, and the iommu daemon all
failed silently on real Arrow Lake hardware before this commit.

**Phase G.2 — cpufreqd HWP support (`d24d0e217`).** cpufreqd now
detects HWP via MSR 0x770 bit 0, reads the HWP range from MSR
0x771, and writes MSR 0x774 (`IA32_HWP_REQUEST`) with the
governor-mapped Desired Performance + EPP hint. Falls back to
legacy `IA32_PERF_CTL` (MSR 0x199) on non-HWP CPUs.
Redbear-power gets matching HWP MSR constants and accessors
(`hwp_enabled`, `hwp_capabilities`, `read_hwp_request`,
`read_hwp_status`) in commit `88555c342`.

**Phase G.6 — acpid `/scheme/acpi/processor/` route (`c335553`).**
Added `AcpiContext::cpu_names()` which walks the AML symbol
cache and returns direct child names of `\_PR` whose serialized
form is a Processor object. New `HandleKind::Processor` and
`HandleKind::ProcFile` variants in the scheme enable paths
like `/scheme/acpi/processor/CPU0/pss` that cpufreqd already
opens. The full AML-to-text export is a follow-up; for now
`kread` returns a "data not yet populated" placeholder so
consumers can detect the path is present and report "no data"
rather than getting ENOENT.

**What was NOT done (out of scope for this session):**

- **Phase G.3** — S0ix (Modern Standby) in kernel. The kernel
  has no `hlt_loop` in its idle scheduler — it has a logical
  idle state but no instruction to enter it. Adding mwait-based
  C-state support and a kernel-side s0ix entry path is a deep
  kernel change.
- **Phase G.4** — full C-state driver. Depends on Phase G.3.
- **Phase G.5** — S0ix device quiesce (GMA + NPU D3Hot). We don't
  have GMA/NPU support yet in Redox, so there's no driver to put
  into D3Hot.
- **Phase G.7** — redbear-power HWP UI / S0ix indicator. The MSR
  accessors (Phase G.2) provide the data, but the TUI doesn't
  yet read them on a timer. Phase G.7 was deferred to a follow-up.
- **Phase G.8** — LG Gram 2025 DMI quirks. Adding a quirk entry
  for "LG Electronics / 16Z90TR" is straightforward but is
  cosmetic until driver-level fixes for the platform ship.

**Versions on the 0.2.4 branch (per AGENTS.md § "In-house crate
versioning"):**

- `local/sources/base` (acpid, hwd, pcid) → 0.1.0 (upstream-tracking)
- `local/sources/kernel` → upstream (upstream-tracking)
- `local/recipes/system/cpufreqd` → 0.2.4 ✓
- `local/recipes/system/redbear-sessiond` → 0.2.4 ✓
- `local/recipes/system/redbear-power` → 0.2.4 ✓

### Git server docs (`README.md`, `local/AGENTS.md`, commit `0c60adc6b`)

- Added a canonical **"Our Git Server"** section to both `README.md` and
  `local/AGENTS.md`. Documented the canonical server (gitea.redbearos.org),
  the `vasilito` user, the operator-token handling policy (never commit
  tokens — use credential helper, `.netrc`, or `$REDBEAR_GITEA_TOKEN`),
  the repo map (historical at time of writing — `vasilito/redbear-os-base`,
  `vasilito/redbear-os-kernel`, `vasilito/redbear-os-relibc`; since merged
  as `submodule/<component>` branches inside `RedBear-OS` per the
  SINGLE-REPO RULE in `local/AGENTS.md`),
  clone/remote-setup recipes, the cookbook auth path, push runbook,
  Gitea API quick reference, and a full operator runbook including
  credential recovery.

### Build-system hardening plan (`local/docs/BUILD-SYSTEM-IMPROVEMENTS.md`, commit `41045fd2f`)

- Added four S-sized items #11–#14 documenting build-system ergonomics
  observed during the input-stack diagnosis:

  - **#11:** Inner-fork git repo origin points to upstream Redox instead of
    Red Bear's gitea — push footgun.
  - **#12:** Outer Red Bear repo cannot show inline diffs for the nested
    `local/sources/base/` git repo (submodule pointer dirty).
  - **#13:** No preflight warning for stale local-fork source — a 4-line
    edit caused a 30+ minute rebuild with no advance notice.
  - **#14:** `-nographic` + OVMF boot is too slow for time-budgeted
    post-fix QEMU verification; recommend BIOS + KVM path.

  Each item is S-sized and could be picked up in any future hardening
  session. None are blockers.

### Misc

- Removed the hallucinated `gitea` git remote that pointed at the
  non-existent `https://gitea.redbear.com/redox-os/relibc.git`.

## 2026-04-14

- Added a canonical GitHub-visible Red Bear OS implementation plan under `docs/` and linked it from the main README and docs index.
- Added a user-visible GitHub-facing "What's New" section to the root README and linked it to this running changelog.
- Added a new `redbear-kde` configuration and documented current KDE bring-up status as in-progress rather than not started.
- Refreshed top-level and docs status notes so historical roadmap documents no longer read as the current repo state.
- Expanded shipped Red Bear system tooling and config coverage around runtime diagnostics, native hardware listing, and Redox-native networking flows.
- Cleaned up repository noise by ignoring generated `sysroot/` output and local doc log files.

## 2026-04-27 — Boot Process Overhaul

### Real Wayland Compositor
- New `redbear-compositor` package: 690-line Rust Wayland display server
- Full XDG shell protocol support (15/15 Wayland protocols)
- Replaces KWin stubs that created placeholder sockets
- `redbear-compositor-check` diagnostic tool
- Integration test suite verifying protocol compliance

### Intel GPU Driver Expansion
- Gen8-Gen12 supported: Skylake, Kaby Lake, Coffee Lake, Cannon Lake, Ice Lake, Tiger Lake, Alder Lake, DG2, Meteor Lake, Arrow Lake, Lunar Lake, Battlemage
- 200+ device IDs from Linux 7.0 i915 reference
- Gen4-Gen7 recognized with clear unsupported messages
- Display fixes: pipe count, page flip, EDID skeleton

### VirtIO GPU Driver
- New VirtIO GPU DRM/KMS backend for QEMU testing
- Full GpuDriver trait implementation (11 methods)

### Kernel Fixes
- 4GB RAM boot hang fixed (MEMORY_MAP overflow at 512 entries)
- Canary chain added for boot diagnosis

### Live ISO
- Preload capped at 1 GiB for large ISOs
- Partial preload with informative messaging

### DRM/KMS Integration
- KWIN_DRM_DEVICES wired through entire greeter chain
- Compositor auto-detects DRM device with 5-second wait

### Boot Daemons
- dhcpd: auto-detects network interface
- i2c-gpio-expanderd/ucsid: hardened I2C decode with retry

### Documentation
- BOOT-PROCESS-IMPROVEMENT-PLAN.md
- PROFILE-MATRIX.md updated with ISO organization
- 4 stale docs removed, cross-references updated