feat: P0-P6 kernel scheduler + relibc threading comprehensive implementation

P0-P2: Barrier SMP, sigmask/pthread_kill races, robust mutexes, RT scheduling, POSIX sched API
P3: PerCpuSched struct, per-CPU wiring, work stealing, load balancing, initial placement
P4: 64-shard futex table, REQUEUE, PI futexes (LOCK_PI/UNLOCK_PI/TRYLOCK_PI), robust futexes, vruntime tracking, min-vruntime SCHED_OTHER selection
P5: setpriority/getpriority, pthread_setaffinity_np, pthread_setname_np, pthread_setschedparam (Redox)
P6: Cache-affine scheduling (last_cpu + vruntime bonus), NUMA topology kernel hints + numad userspace daemon

Stability fixes: make_consistent stores 0 (dead TID fix), cond.rs error propagation, SPIN_COUNT adaptive spinning, Sys::open &str fix, PI futex CAS race, proc.rs lock ordering, barrier destroy

Patches: 33 kernel + 58 relibc patches, all tracked in recipes
Docs: KERNEL-SCHEDULER-MULTITHREAD-IMPROVEMENT-PLAN.md updated, SCHEDULER-REVIEW-FINAL.md created
Architecture: NUMA topology parsing stays userspace (numad daemon), kernel stores lightweight NumaTopology hints

local/docs/DEVICE-INIT-COMPREHENSIVE-IMPROVEMENT-PLAN.md

@@ -0,0 +1,735 @@
+# Red Bear OS Low-Level Device Initialization — Comprehensive Improvement Plan
+
+**Date:** 2026-04-30
+**Scope:** Complete reassessment of boot-time device initialization: daemon inventory, firmware loading, driver model, bus enumeration, controller support, hardware validation
+**Reference:** Linux 7.0 kernel device init model (full source available for comparison)
+**Status:** Assessment phase — this document is the execution plan
+
+## 1. Executive Summary
+
+Red Bear OS has crossed the fundamental bring-up threshold: the system boots to a login prompt on
+both QEMU and bounded bare-metal hardware (AMD Ryzen), device daemons start in a defined order,
+and major subsystems (ACPI, PCI, USB/xHCI, NVMe, network) have in-tree implementations.
+
+However, the device initialization stack is **not release-grade**. Key deficiencies vs Linux 7.0:
+
+| Gap | Severity | Impact |
+|-----|----------|--------|
+| No proper device driver model (bus/device/driver binding) | CRITICAL | No deferred probing, no async init, no hotplug |
+| No uevent/hotplug infrastructure (udev-shim is static enumerator only) | CRITICAL | No device add/remove notification; `udev-shim` is misnamed — it does a single PCI scan, not real udev |
+| No EHCI/OHCI/UHCI USB controllers | HIGH | USB keyboard not reliable on bare metal |
+| initfs vs rootfs driver duality — drivers started in initfs may conflict with rootfs drivers | HIGH | No explicit handoff contract for devices initialized in initfs |
+| No hardware validation for MSI-X, IOMMU, xHCI interrupts | HIGH | QEMU-proven only; real hardware behavior unknown |
+| No suspend/resume or runtime power management | HIGH | No S3/S4 sleep, no device power gating |
+| No CPU frequency scaling or thermal management | MEDIUM | Battery life, thermal throttling absent |
+| No hardware RNG daemon, no SMBIOS/DMI runtime | MEDIUM | Missing entropy source, missing quirk data |
+| No PCIe AER, no advanced error reporting | MEDIUM | Silent device failures |
+| Firmware loading GPU-only (no Wi-Fi, audio, media) | MEDIUM | Blocks iwlwifi, Bluetooth, media acceleration |
+| No device naming policy or persistent device names | MEDIUM | `/dev/` names unstable across boots |
+| No kernel cmdline for device parameterization | LOW | No runtime device config without rebuild |
+| ACPI startup still carries panic-grade `expect` paths | HIGH | Boot fragility on diverse hardware |
+| `acpid` `_S5` shutdown not release-grade | HIGH | Unclean shutdown on some platforms |
+| Wi-Fi transport asserts on MSI-X (no legacy IRQ fallback) | HIGH | Wi-Fi won't work on older platforms |
+| No EHCI companion controller routing for USB keyboards | HIGH | USB keyboard may be unreachable on some bare metal |
+| No io_uring or epoll for async I/O in device daemons | LOW | Throughput ceiling for NVMe |
+
+### Bottom Line
+
+**Red Bear OS boots, but device initialization is naive by Linux 7.0 standards.** The microkernel
+scheme-based driver model is architecturally sound, but the implementation lacks the maturity,
+error resilience, hardware coverage, and power management depth that Linux 7.0 has accumulated
+over 30 years of driver development.
+
+This plan defines a structured path to close these gaps over 5 phases (26-40 weeks).
+
+## 2. Current State Assessment
+
+### 2.1 Boot Flow
+
+```
+UEFI firmware → Bootloader → Kernel (kstart→kmain) →
+userspace_init → bootstrap (procmgr) → initfs init →
+├── Phase 1 (initfs): logd, nulld, randd, zerod, rtcd, ramfs
+├── Phase 1 (initfs): inputd, lived
+├── Phase 1 (initfs): vesad, fbbootlogd, fbcond (graphics target)
+├── Phase 1 (initfs): hwd, pcid-spawner-initfs, ps2d (drivers target)
+├── Phase 1 (initfs): rootfs mount → switchroot
+├── Phase 2 (rootfs): ipcd, ptyd, pcid-spawner (base target)
+│   ├── pcid-spawner spawns drivers matching PCI IDs:
+│   │   ├── Storage: ahcid, ided, nvmed, virtio-blkd, usbscsid
+│   │   ├── Network: e1000d, rtl8168d, rtl8139d, ixgbed, virtio-netd
+│   │   ├── Graphics: vesad, ihdgd, virtio-gpud
+│   │   ├── Input: ps2d, usbhidd
+│   │   ├── Audio: ihdad, ac97d, sb16d
+│   │   └── USB: xhcid, usbhubd
+│   ├── smolnetd → dhcpd (network target)
+│   ├── firmware-loader, udev-shim, evdevd, wifictl
+│   ├── dbus-daemon → redbear-sessiond, seatd
+│   └── console/getty → login prompt
+```
+
+### 2.2 Daemon Inventory — Existence and Quality
+
+#### Core Initfs Daemons (20 services)
+
+| Daemon | Quality | Notes |
+|--------|---------|-------|
+| `logd` | ✅ Hardened | Zero unwrap/expect; file descriptors, setrens, process loop |
+| `nulld` | ✅ Hardened | Zero unwrap/expect |
+| `randd` | ✅ Hardened | CPUID chain hardened; 8 test-only unwraps |
+| `zerod` | ✅ Hardened | Args default + graceful exit |
+| `rtcd` | ✅ Present | x86 RTC driver; minimal attack surface |
+| `ramfs@` | ✅ Present | Template service for RAM filesystems |
+| `inputd` | ✅ Hardened | 14 panic sites converted; partial vt events, buffer sizes |
+| `lived` | ✅ Present | Live disk daemon |
+| `vesad` | ✅ Hardened | 20 fixes; FRAMEBUFFER env, EventQueue, event loop, scheme |
+| `fbbootlogd` | ✅ Hardened | 14 fixes; VT handle, graphics handle, dirty_fb |
+| `fbcond` | ✅ Hardened | 14 fixes; VT parse, event loop, writes, scheme, display |
+| `hwd` | ✅ Present | ACPI/DeviceTree boot handler |
+| `pcid-spawner-initfs` | ✅ Hardened | initfs variant; oneshot_async |
+| `ps2d` | ✅ Hardened | Controller init drains stale output; QEMU proof |
+| `bcm2835-sdhcid` | ✅ Present | ARM-only (Raspberry Pi) |
+
+#### Core Rootfs Daemons (9 base services)
+
+| Daemon | Quality | Notes |
+|--------|---------|-------|
+| `ipcd` | ✅ Present | IPC daemon |
+| `ptyd` | ✅ Present | Pseudo-terminal daemon |
+| `pcid-spawner` | ✅ Hardened | Changed to oneshot_async (was blocking init); logs device info |
+| `sudo` | ✅ Present | Privilege daemon |
+| `smolnetd`/`netstack` | ✅ Present | TCP/IP stack |
+| `dhcpd` | ✅ Present | DHCP client |
+| `audiod` | ✅ Present | Audio multiplexer |
+
+#### PCI-Matched Device Drivers (pcid-spawner, 25+ drivers)
+
+| Category | Drivers | Quality |
+|----------|---------|---------|
+| Storage | ahcid, ided, nvmed, virtio-blkd, usbscsid | ✅ All hardened (Wave 4 complete) |
+| Network | e1000d, rtl8168d, rtl8139d, ixgbed, virtio-netd | ✅ All hardened |
+| Graphics | vesad, ihdgd, virtio-gpud | ✅ All hardened |
+| Input | ps2d, usbhidd | ✅ All hardened |
+| Audio | ihdad, ac97d, sb16d | ✅ All hardened |
+| USB | xhcid, usbhubd, usbctl, ucsid | ✅ xhcid has 88 Red Bear patches |
+| GPIO/I2C | gpiod, i2cd, intel-gpiod, amd-mp2-i2cd, dw-acpi-i2cd, i2c-gpio-expanderd, i2c-hidd, intel-thc-hidd, intel-lpss-i2cd | ✅ Present |
+| System | pcid, pcid-spawner, acpid | ✅ Core infra; pcid hardened Wave 1-2 |
+| VirtualBox | vboxd | ✅ x86 only |
+
+#### Custom Red Bear Daemons
+
+| Daemon | Quality | Notes |
+|--------|---------|-------|
+| `firmware-loader` | ✅ Well-tested | 18 unit tests; scheme:firmware with read/mmap; no signing |
+| `redox-drm` | 🚡 Bounded compile | AMD+Intel+VirtIO display; 68 tests; no HW validation |
+| `amdgpu` | 🚡 Bounded compile | Imported Linux DC/TTM/core; partial display glue |
+| `iommu` | 🚡 QEMU-proven | AMD-Vi detection + first-use proof; no HW validation |
+| `udev-shim` | ✅ Present | Scheme:udev with device enumeration |
+| `evdevd` | ✅ Present | Linux-compatible evdev interface |
+| `redbear-sessiond` | ✅ Present | D-Bus login1 session broker |
+| `redbear-wifictl` | 🚡 Host-tested | Wi-Fi control daemon; no real hardware |
+| `redbear-iwlwifi` | 🚡 Host-tested | Intel transport; ~2450 lines C + ~1550 lines Rust; 119 tests |
+| `redbear-btusb` | 🔴 Experimental | BLE-first; USB-attached only; QEMU validation in progress |
+| `redbear-authd` | ✅ Present | Local-user authentication |
+| `redbear-greeter` | 🚡 Partial | Greeter orchestrator; Qt Wayland integration broken |
+| `redbear-netctl` | ✅ Present | Network profile management |
+| `redbear-hwutils` | ✅ Present | lspci, lsusb, phase checkers |
+
+### 2.3 Firmware Loading
+
+**What exists:**
+- `scheme:firmware` daemon (`firmware-loader`) indexes blobs from `/lib/firmware/`
+- `linux-kpi` provides `request_firmware()` via Rust FFI
+- AMD GPU blobs (675 .bin files) in `local/firmware/amdgpu/` (gitignored, fetched from linux-firmware)
+- Intel DMC display blobs fetchable via `fetch-firmware.sh --vendor intel --subset dmc`
+- Two fetch mechanisms: standalone script (selective) + build-time meta-package (full linux-firmware)
+- `PCI_QUIRK_NEED_FIRMWARE` flag defined (bit 11), but never checked by any driver
+
+**What is MISSING vs Linux 7.0 `firmware_class`:**
+- No firmware signing/verification (no `module_sig_check` equivalent)
+- No `request_firmware_nowait` with uevent dispatch to userspace helper (Linux uses `/sys/$DEVPATH/loading` + `/sys/$DEVPATH/data` + uevent to notify udev)
+- No persistent firmware cache between boots (in-memory only; Linux caches during suspend for resume-fastpath)
+- No fallback firmware variant search (if dmcub_dcn31.bin missing, try dmcub_dcn30.bin; Linux has per-driver firmware search paths)
+- No `/sys/firmware/` interface (Linux exposes firmware loading status via sysfs)
+- No firmware preloading at driver bind time
+- No timeout for synchronous `request_firmware` (blocks forever; Linux times out after ~60s with uevent fallback)
+- No platform firmware fallback (Linux can search UEFI firmware volumes via `firmware_request_platform()`)
+- No Wi-Fi firmware blobs (iwlwifi, ath10k, etc.)
+- No Bluetooth firmware blobs
+- No audio/media codec firmware
+- Firmware lookup limited to 3 hardcoded paths (Linux searches: `/lib/firmware/`, `/lib/firmware/updates/`, `/lib/firmware/$KVER/`, `/usr/lib/firmware/`, `/usr/share/firmware/`, plus custom path via kernel param)
+
+### 2.4 Hardware Validation Status
+
+| Subsystem | QEMU | Bare Metal | Notes |
+|-----------|------|------------|-------|
+| ACPI boot | ✅ | ✅ (AMD) | Boot-baseline; `_S5` shutdown not release-grade |
+| x2APIC/SMP | ✅ | ✅ | Multi-core works |
+| PCI enumeration | ✅ | ✅ | pcid enumerates devices |
+| MSI-X | ✅ (virtio-net) | ❌ | No hardware proof |
+| IOMMU/AMD-Vi | ✅ (first-use) | ❌ | Detection works; no HW validation |
+| xHCI interrupt | ✅ | ❌ | Interrupt mode proven; no HW |
+| USB storage | ✅ (readback) | ❌ | QEMU mass-storage proof |
+| NVMe | ✅ | ❌ | Builds; no HW |
+| AHCI | ✅ | ❌ | Builds; no HW |
+| Network (e1000/virtio) | ✅ | ❌ | QEMU only |
+| PS/2 keyboard | ✅ | ✅ | QEMU + AMD bare metal |
+| USB keyboard | ✅ (QEMU HID) | ⚠️ | Not reliable on bare metal |
+| Wi-Fi | ❌ | ❌ | Host-tested transport only |
+| Bluetooth | ❌ | ❌ | Experimental BLE; QEMU in progress |
+
+### 2.5 Comparison with Linux 7.0 Device Init Model
+
+#### 2.5.1 Linux Initcall Ordering (Reference)
+
+Linux uses a 10-level initcall system for boot-phase ordering:
+
+| Level | Macro | Typical Count | Example Uses |
+|-------|-------|---------------|--------------|
+| 0 | `pure_initcall` | ~few | Pure infrastructure |
+| early | `early_initcall` | ~446 | mm init, early console, DT scan |
+| 1 | `core_initcall` | ~614 | Workqueues, RCU, memory allocators |
+| 2 | `postcore_initcall` | ~150 | Clocksource, scheduler, IRQ core |
+| 3 | `arch_initcall` | ~751 | PCI bus init, ACPI table parsing, CPU bringup |
+| 4 | `subsys_initcall` | ~573 | PCI enumerate, USB core, networking core, block |
+| 5 | `fs_initcall` | ~1372 | Filesystem registration |
+| 6 | `device_initcall` | ~1211 | Most drivers; `module_init()` maps here |
+| 7 | `late_initcall` | ~440 | Late init, debug, tracing |
+
+Red Bear OS has **no equivalent ordering mechanism** — the TOML-based init uses `requires_weak`
+for loose ordering but has no topological sort depth, no `Before`/`After` fields, no explicit
+init phases beyond the coarse initfs/rootfs split.
+
+#### 2.5.2 Feature Comparison Table
+
+| Feature | Linux 7.0 | Red Bear OS | Gap |
+|---------|-----------|-------------|-----|
+| **Driver model** | `bus_type` → `device_driver` → `probe()` binding with match tables | `pcid-spawner` spawns drivers by PCI class/vendor/device | 🟡 Partial — single-shot spawn, no rebinding |
+| **Deferred probing** | `driver_deferred_probe` — retries when dependency arrives; `-EPROBE_DEFER` triggers retry on any successful probe | None | 🔴 Missing — must be present at boot |
+| **Async probing** | `async_probe` — parallel driver init via kthreadd workers | Sequential spawn only | 🟡 Partial — oneshot_async for launch but not true async init |
+| **Hotplug** | uevent netlink → udev → driver bind/unbind; `/sbin/hotplug` path | `udev-shim` is a **static PCI enumerator** — one scan at boot, no event callbacks, no device removal handling | 🔴 Missing — no hotplug infrastructure at all |
+| **Firmware loading** | `firmware_class` with `request_firmware`, user helper, caching | `scheme:firmware` + `linux-kpi` request_firmware | 🟡 Partial — no uevent/helper/caching |
+| **USB controllers** | xHCI, EHCI, OHCI, UHCI — all supported | xHCI only | 🔴 Missing — EHCI/OHCI/UHCI absent |
+| **USB device classes** | HID, storage, audio, video, CDC, vendor, etc. | HID, hub, storage (BOT), CSI (UCSI) | 🟡 Partial — many classes missing |
+| **Power management** | Suspend/resume, runtime PM, CPU freq scaling, thermal | `_S5` shutdown only | 🔴 Missing — no S3/S4/PM |
+| **Interrupt handling** | Full APIC/x2APIC, MSI/MSI-X, affinity, NMI, MCE | APIC/x2APIC; MSI-X via quirks | 🟡 Partial — no affinity, no NMI watchdog |
+| **IOMMU** | AMD-Vi, Intel VT-d with DMA remapping + IR | AMD-Vi detection + first-use proof | 🟡 Partial — no VT-d, no hardware |
+| **ACPI namespace** | Full namespace: devices, thermal, battery, processor, etc. | Boot-baseline: MADT, FADT, `_S5`, bounded power | 🟡 Partial — many ACPI objects missing |
+| **PCIe features** | AER, ACS, ATS, PRI, PASID, SR-IOV | Basic PCI config space only | 🔴 Missing — no advanced PCIe |
+| **Device naming** | Predictable network/storage names (systemd udev) | None | 🟡 Partial — no naming policy |
+| **Hardware RNG** | `hw_random` framework, multiple drivers | None | 🔴 Missing |
+| **CPU frequency** | `cpufreq` governors | None | 🔴 Missing |
+| **Thermal management** | `thermal` framework + drivers | None | 🔴 Missing |
+| **SMBIOS/DMI** | Full DMI table exposure via sysfs | Quirks system has DMI data | 🟡 Partial — not runtime-exposed |
+| **Kernel cmdline** | Device parameters via boot cmdline | None | 🔴 Missing |
+
+## 3. Implementation Phases
+
+### Phase 1 — Driver Model Maturation (Weeks 1-8)
+
+**Goal:** Establish a proper device driver model with binding semantics, deferred probing,
+and error resilience — bringing the driver infrastructure to Linux 7.0 par without rewriting
+existing drivers.
+
+#### 1.1 Device-Driver Binding Model (Week 1-3)
+
+Create a `redox-driver-core` library providing Linux-style bus/device/driver abstractions:
+
+```
+Device → Driver matching:
+  pcid: class=0x01, subclass=0x08 → nvmed
+  pcid: vendor=0x8086, device=0x10D3 → e1000d
+
+Driver probe() returns:
+  Ok(())       → device bound, driver active
+  Err(ENODEV)  → device not supported by this driver
+  Err(EAGAIN)  → dependency not available, DEFER probe
+  Err(...)      → fatal error, device unusable
+```
+
+**Deliverables:**
+- `redox-driver-core` crate with `Bus`, `Device`, `Driver` traits
+- `pcid` exposes devices via new scheme: `scheme:pci/devices/{id}/bind`
+- `pcid-spawner` replaced by `driver-manager` daemon that:
+  - Reads driver match tables from `/lib/drivers.d/*.toml`
+  - Probes drivers in priority order
+  - Supports deferred probing (EAGAIN → retry when dependency appears)
+  - Supports driver unbind/rebind
+- All existing `pcid.d/*.toml` match files migrated to new format
+- Backward compatible: existing pcid-spawner behavior preserved as fallback
+
+#### 1.2 Async Device Probing (Week 4-5)
+
+**Deliverables:**
+- `driver-manager` probes independent device trees in parallel (using Rust async or threads)
+- Device init order defined by dependency DAG, not sequential spawn
+- Timing observability: log probe duration per driver
+- `CONFIG_PARALLEL_PROBE` equivalent: max concurrent probes tunable via config TOML
+
+#### 1.3 Driver Parameter System (Week 6-7)
+
+**Deliverables:**
+- Kernel cmdline parsing in bootloader (e.g., `redbear.nvme.irq_mode=msi`)
+- `/scheme/sys/driver/{name}/parameters` read/write
+- Driver authors declare parameters via derive macro
+- `lspci -v` shows per-device parameters
+
+#### 1.4 Hotplug Infrastructure (Week 7-8)
+
+**Deliverables:**
+- PCIe hotplug: `pcid` detects surprise removal/addition, emits uevent
+- USB hotplug: `xhcid` emits uevent on device attach/detach
+- `udev-shim` enhanced to receive uevents and trigger driver binding
+- `driver-manager` handles hot-add (probe driver) and hot-remove (unbind driver)
+- Initial scope: PCIe hotplug and USB hotplug only; Thunderbolt deferred
+
+**Phase 1 Exit Criteria:**
+- New driver binding model functional for 3+ existing drivers (nvmed, e1000d, xhcid)
+- Deferred probing works: driver returning EAGAIN retries when dependency scheme appears
+- Async probing measurable: 2+ independent PCI devices probe concurrently
+- Hotplug works: USB device attach/detach triggers udev-shim + driver bind/unbind in QEMU
+- All 25+ existing drivers still compile and function (backward compatibility)
+
+### Phase 2 — Controller Coverage & Hardware Validation (Weeks 5-14)
+
+**Goal:** Fill the critical controller gaps (USB EHCI/OHCI/UHCI) and validate the
+existing controller stack on real hardware — especially MSI-X, IOMMU, and xHCI.
+
+#### 2.1 USB Controller Family Completion (Week 5-9)
+
+This is the **highest-impact controller gap** because it directly blocks reliable
+USB keyboard input on bare metal where the keyboard may be routed through companion
+controllers rather than xHCI.
+
+**Deliverables:**
+- `ehcid` daemon — EHCI (USB 2.0) host controller driver
+- `ohcid` daemon — OHCI (USB 1.1) host controller driver for non-Intel chipsets
+- `uhcid` daemon — UHCI (USB 1.1) host controller driver for Intel chipsets
+- USB companion controller routing: when xHCI owns the ports, companion controllers
+  hand off low/full-speed devices to xHCI transparently
+- `usb-manager` daemon orchestrates multi-controller topology:
+  - Single `scheme:usb` root exposing all buses
+  - Device path stability across controller types
+  - Port routing table for companion controller ownership handoff
+- USB 3.1/3.2 SuperSpeedPlus support in xhcid (10 Gbps, 20 Gbps)
+- USB-C PD/alt-mode awareness in `ucsid`
+
+**Implementation approach:**
+- EHCI: Reference Linux `drivers/usb/host/ehci-hcd.c` (~6000 lines) and FreeBSD `sys/dev/usb/controller/ehci.c`
+- OHCI: Reference Linux `drivers/usb/host/ohci-hcd.c` (~3000 lines)
+- UHCI: Reference Linux `drivers/usb/host/uhci-hcd.c` (~2500 lines)
+- All three controllers use the same `scheme:usb` interface — class daemons (usbhubd, usbhidd, usbscsid) work unchanged
+
+#### 2.2 xHCI Device-Level Hardening (Week 8-10)
+
+Per the existing `XHCID-DEVICE-IMPROVEMENT-PLAN.md`:
+
+**Deliverables:**
+- Atomic device attach publication (prevent half-attached devices)
+- Bounded device detach and purge
+- Configure rollback on failure
+- Real PM sequencing (U0/U1/U2/U3 transitions)
+- Enumerator cleanup and timing hardening
+- Growable event ring under sustained activity
+
+#### 2.3 MSI-X Hardware Validation (Week 8-11)
+
+Per the existing `IRQ-AND-LOWLEVEL-CONTROLLERS-ENHANCEMENT-PLAN.md` Priority 1:
+
+**Deliverables:**
+- AMD GPU MSI-X validation: prove MSI-X vectors fire correctly on real AMD hardware
+- Intel GPU MSI-X validation: prove MSI-X on Intel hardware
+- NVMe MSI-X validation: prove per-queue interrupt vectors
+- xHCI MSI-X validation: prove interrupt-driven event ring on real hardware (not just QEMU)
+- Verified MSI-X → MSI → legacy IRQ fallback on all tested hardware
+- Logged CPU/vector affinity behavior
+- At minimum one AMD and one Intel bare-metal test report per device class
+
+#### 2.4 IOMMU Hardware Bring-Up (Week 9-14)
+
+Per the existing `IRQ-AND-LOWLEVEL-CONTROLLERS-ENHANCEMENT-PLAN.md` Priority 2:
+
+**Deliverables:**
+- Validated AMD-Vi initialization on real AMD hardware
+- Device table / command buffer / event log validation
+- Interrupt remapping validation
+- Intel VT-d initial detection and register mapping (not full bring-up)
+- IOMMU fault-path validation: inject fault, verify event log capture
+- DMA remapping proof: verify device DMA is translated through IOMMU page tables
+- Negative-result documentation if hardware still fails
+
+#### 2.5 ACPI Wave 1-2 Completion (Week 10-12)
+
+Per the existing `ACPI-IMPROVEMENT-PLAN.md` Waves 1-2:
+
+**Deliverables:**
+- Finish replacing panic-grade `expect` paths in `acpid` startup
+- Define and document AML bootstrap contract (explicit RSDP_ADDR producer)
+- Table-specific reject/warn/degrade/fail rules implemented
+- Deterministic `_S5` derivation (not dependent on PCI timing)
+- Explicit shutdown/reboot result semantics
+- Bounded shutdown proof on real AMD and Intel hardware
+- Sleep-state scope explicit: S5 only; S3/S4 explicitly deferred
+
+**Phase 2 Exit Criteria:**
+- At least one EHCI or OHCI/UHCI driver functional in QEMU
+- USB keyboard reliably reachable on bare metal AMD and Intel (via xHCI, EHCI, or companion routing)
+- MSI-X validated on at least one real AMD GPU and one real Intel GPU
+- IOMMU AMD-Vi validated on at least one real AMD machine
+- ACPI `_S5` shutdown works on at least one real AMD and one real Intel machine
+- ACPI startup contains zero panic-grade paths reachable from firmware input
+
+### Phase 3 — Power Management & Platform Services (Weeks 12-20)
+
+**Goal:** Add suspend/resume, CPU frequency scaling, thermal management, and hardware
+RNG — bringing platform services to Linux 7.0 par for basic functionality.
+
+#### 3.1 ACPI Power Management (Week 12-14)
+
+Per the existing `ACPI-IMPROVEMENT-PLAN.md` Waves 3-4:
+
+**Deliverables:**
+- Honest `/scheme/acpi/power` surface: exposes only behavior with runtime evidence
+- Consumer-visible distinction between unsupported, unavailable, and populated power state
+- Reduced surface: remove misleading empty-success defaults
+- AML physmem/EC failure propagation: no correctness-critical fabricated values
+- EC error typing and documented widened-access behavior
+- Documented AML mutex timeout behavior
+
+#### 3.2 Suspend/Resume (S3 Sleep) — Initial Implementation (Week 13-16)
+
+**Deliverables:**
+- Kernel: save/restore CPU context (CR0-CR4, MSRs, IDT/GDT, FPU/SSE/AVX state)
+- Kernel: ACPI S3 (suspend-to-RAM) entry via `_S3` AML method
+- Kernel: wake vector registration and resume path
+- `acpid`: expose `/scheme/acpi/sleep` with `S3` and `S5` states
+- Device contract: `suspend()` callback on each scheme daemon
+  - Storage: flush caches, park heads (if spinning)
+  - Network: bring link down, save MAC filter state
+  - USB: save controller/port state
+  - Graphics: save mode, blank display
+- `driver-manager`: suspend devices in dependency order, resume in reverse
+- Initial scope: S3 only on test hardware; S4 (hibernate) explicitly deferred
+
+#### 3.3 CPU Frequency Scaling (Week 14-16)
+
+**Deliverables:**
+- `cpufreqd` daemon reading ACPI `_PSS` / `_PPC` objects
+- Intel: P-state MSR writes (IA32_PERF_CTL)
+- AMD: P-state MSR writes + CPPC awareness
+- Governors: `performance` (max freq), `powersave` (min freq), `ondemand` (load-based)
+- `/scheme/cpufreq` for reading/setting governor and frequency
+- `redbear-info` shows current frequency and governor
+
+#### 3.4 Thermal Management (Week 15-17)
+
+**Deliverables:**
+- `thermald` daemon reading ACPI thermal zone objects (`_TMP`, `_PSV`, `_TC1`, `_TC2`)
+- Active cooling: fan control via ACPI `_SCP`
+- Passive cooling: CPU throttling via cpufreqd integration
+- Critical shutdown: if temperature exceeds `_CRT`, initiate clean shutdown
+- `/scheme/thermal` for reading zone temperatures and trip points
+- `redbear-info` shows thermal zone status
+
+#### 3.5 Hardware RNG (Week 16-17)
+
+**Deliverables:**
+- `hwrngd` daemon reading hardware RNG sources:
+  - x86 RDRAND/RDSEED instructions
+  - TPM 2.0 random number generator (if present)
+  - VirtIO entropy device
+- `scheme:hwrng` feeding into `randd` entropy pool
+- `/scheme/hwrng` exposes raw entropy and health status
+- Linux 7.0 `hw_random` framework ported conceptually (not literally)
+
+#### 3.6 PCIe Advanced Error Reporting (Week 17-18)
+
+**Deliverables:**
+- `pcid` exposes AER capability registers via `/scheme/pci/{dev}/aer`
+- AER error detection: correctable and uncorrectable error status registers
+- Error logging: decode error source (data link, transaction, poison TLP, etc.)
+- `aer-inject` utility for testing error paths
+- Initial scope: error detection and logging only; error recovery (device reset path) deferred
+
+#### 3.7 SMBIOS/DMI Runtime Exposure (Week 18-20)
+
+**Deliverables:**
+- `dmidecode`-equivalent utility using `acpid` DMI scheme
+- `/scheme/dmi` exposes SMBIOS entry point and table data
+- `lspci -v` shows DMI-based quirk annotations
+- DMI data feeding into `redbear-info` for platform identification
+- Integration with existing quirks system: DMI match rules validated at runtime
+
+**Phase 3 Exit Criteria:**
+- S3 suspend/resume works on at least one real machine (AMD or Intel)
+- CPU frequency scaling observable via `redbear-info`
+- Thermal zone temperature readable and critical shutdown testable
+- Hardware RNG feeding entropy pool
+- PCIe AER errors logged on capable hardware
+- DMI data accessible via scheme and tools
+- All new schemes documented with test procedures
+
+### Phase 4 — Firmware Infrastructure & Wi-Fi Validation (Weeks 16-24)
+
+**Goal:** Close firmware loading gaps, complete Wi-Fi hardware validation with real
+firmware, and establish firmware management as a first-class platform service.
+
+#### 4.1 Firmware Loading Gap Closure (Week 16-18)
+
+**Deliverables:**
+- `request_firmware_nowait` with proper uevent dispatch:
+  - Async request → uevent → `udev-shim` listens → `firmware-loader` serves blob
+  - Timeout: if firmware not available within configurable timeout, fail gracefully
+- Firmware fallback variant search:
+  - If `dmcub_dcn31.bin` not found, try `dmcub_dcn30.bin`, `dmcub_dcn20.bin`
+  - Per-driver fallback chain defined in `/etc/firmware-fallbacks.d/*.toml`
+- Persistent firmware cache (`/var/lib/firmware/`):
+  - Loaded blobs cached on first use; survive daemon restart
+  - Cache invalidation on firmware version change
+- `PCI_QUIRK_NEED_FIRMWARE` enforcement:
+  - Drivers actually check the flag via `pci_has_quirk()`
+  - When flag is set: require firmware at probe time, fail probe if absent
+  - When flag is absent: firmware is optional, warn if missing but continue
+- Fetch Intel Wi-Fi firmware blobs: `fetch-firmware.sh --vendor intel --subset wifi`
+- Fetch Bluetooth firmware blobs where applicable
+- Firmware manifest: `/lib/firmware/MANIFEST.txt` lists all blobs, versions, sources
+
+#### 4.2 Wi-Fi Hardware Validation (Week 16-22)
+
+Per the existing `WIFI-IMPLEMENTATION-PLAN.md`:
+
+**Deliverables:**
+- Real Intel Wi-Fi device (e.g., AX200/AX201/AX210) validated end-to-end
+- `redbear-iwlwifi` transport:
+  - Firmware loaded via `request_firmware()` → `scheme:firmware`
+  - DMA ring operation validated (TX reclaim, RX restock, command dispatch)
+  - Interrupt handling validated (MSI-X or MSI path)
+  - Association/authentication cycle completed with real AP
+- `redbear-wifictl` control plane:
+  - Scan → connect → DHCP → disconnect cycle validated
+  - WPA2-PSK and open network profiles functional
+  - Profile persistence and boot-time application
+- `redbear-netctl` Wi-Fi profiles:
+  - SSID/Security/Key parsing validated
+  - Bounded Wi-Fi lifecycle (prepare → init-transport → activate-nic → connect → disconnect)
+- Wi-Fi runtime diagnostics:
+  - `redbear-phase5-wifi-check` reports link quality, signal strength, connected AP
+  - `redbear-info --verbose` shows Wi-Fi adapter status
+- At minimum one real Intel Wi-Fi chipset validated
+- Legacy IRQ fallback for platforms where MSI-X is unavailable (via quirks)
+
+#### 4.3 Wi-Fi Desktop API (Week 20-24)
+
+**Deliverables:**
+- D-Bus Wi-Fi API on system bus: `org.freedesktop.NetworkManager` subset
+  - `GetDevices`, `GetAccessPoints`, `ActivateConnection`, `DeactivateConnection`
+  - Signal: `AccessPointAdded`, `AccessPointRemoved`, `StateChanged`
+- `redbear-wifictl` exposes D-Bus interface for desktop consumption
+- `redbear-netctl` GUI client for scanning and connecting (Qt6-based, optional)
+- Desktop status bar Wi-Fi indicator (future KDE plasma-nm integration)
+
+**Phase 4 Exit Criteria:**
+- `request_firmware_nowait` with uevent dispatch functional in QEMU
+- PCI_QUIRK_NEED_FIRMWARE enforced in at least one driver (amdgpu or iwlwifi)
+- Intel Wi-Fi chipset validated end-to-end with real AP
+- Wi-Fi scan → connect → DHCP → internet access completed on real hardware
+- Wi-Fi D-Bus API functional for at least get_devices and get_accesspoints
+- Firmware manifest tracks all loaded blobs with versions
+
+### Phase 5 — Bluetooth, Device Policy, Polish (Weeks 20-30)
+
+**Goal:** Bring Bluetooth to validated experimental status, establish device naming policy,
+and polish remaining gaps.
+
+#### 5.1 Bluetooth Hardware Validation (Week 20-24)
+
+Per the existing `BLUETOOTH-IMPLEMENTATION-PLAN.md`:
+
+**Deliverables:**
+- `redbear-btusb` transport validated with real USB Bluetooth adapter
+- `redbear-btctl` HCI host validated:
+  - Controller init sequence (reset, read local features, set event mask)
+  - Device discovery (LE scan → advertising report → connect)
+  - GATT service discovery
+  - Basic data exchange (battery service, device info)
+- BLE peripheral connect/disconnect cycle validated
+- Bluetooth classic (BR/EDR) detection and basic inquiry (connect deferred)
+- `redbear-bluetooth-battery-check` works on real hardware
+- At minimum one real USB Bluetooth adapter validated
+
+#### 5.2 Device Naming Policy (Week 22-24)
+
+**Deliverables:**
+- Predictable network interface names:
+  - `enp0s1` instead of `eth0` (PCIe bus/device/function based)
+  - `/etc/systemd/network/` equivalent rules in `/etc/udev/rules.d/`
+- Predictable storage device names:
+  - NVMe: `nvme0n1` instead of raw scheme path
+  - AHCI: `sd{a,b,c}` assigned by port order
+  - USB storage: `sdX` with stable enumeration
+- `/dev/disk/by-id/`, `/dev/disk/by-path/`, `/dev/disk/by-uuid/` symlinks
+- `udev-shim` enhanced with rule matching (vendor, model, serial, path patterns)
+
+#### 5.3 Device Init Observability (Week 23-25)
+
+**Deliverables:**
+- Boot-time device init timeline: log each device probe start/end with duration
+- `redbear-info --boot` shows device init timeline post-boot
+- Per-device init status: `redbear-info --device pci/00:02.0`
+- Kernel cmdline `redbear.init_verbose` enables verbose device init logging
+- Boot-time warning summary: all drivers that probed with warnings or deferrals
+- Device init health dashboard: `redbear-info --health` shows init status of all subsystems
+
+#### 5.4 Remaining Gaps (Week 24-30)
+
+**Deliverables:**
+- `nvmed` hardware validation: prove NVMe I/O on real hardware
+- `ahcid` hardware validation: prove SATA I/O on real hardware
+- `ihdad` hardware validation: prove audio output on real hardware
+- USB device class coverage expanded:
+  - USB CDC ACM (serial): `usbcdcd` daemon
+  - USB CDC ECM/NCM (ethernet): `usbnetd` daemon (or integrate into existing net drivers)
+  - USB Audio Class 1/2: `usbaudiod` daemon
+- GPU hardware acceleration readiness:
+  - Mesa radeonsi backend proof-of-concept (single draw call)
+  - KMS atomic modesetting proof on real hardware (not just QEMU)
+- `redbear-btusb` autospawn via USB class matching
+- `kstop` shutdown event: gracefully stop all device daemons before power-off
+
+**Phase 5 Exit Criteria:**
+- Bluetooth BLE discovery and basic data exchange works on real hardware
+- Network interfaces use predictable names on QEMU and bare metal
+- Device init timeline observable via `redbear-info --boot`
+- NVMe I/O validated on at least one real NVMe drive
+- Real audio output validated on at least one HDA codec
+- At least one USB device class beyond HID/storage validated (audio, serial, or ethernet)
+- All 25+ existing drivers maintain backward compatibility
+
+## 4. Dependency Graph
+
+```
+Phase 1 (Driver Model) ─────────────────────────────┐
+  ├── 1.1 Binding Model                              │
+  ├── 1.2 Async Probing (after 1.1)                  │
+  ├── 1.3 Driver Parameters (after 1.1)              │
+  └── 1.4 Hotplug (after 1.1)                        │
+                                                     │
+Phase 2 (Controllers) ───────────────────────────────┤
+  ├── 2.1 USB EHCI/OHCI/UHCI (parallel with 1.2)     │
+  ├── 2.2 xHCI Hardening (parallel with 1.2)         │
+  ├── 2.3 MSI-X HW Validation (after 1.1)            │
+  ├── 2.4 IOMMU HW Bring-Up (parallel with 2.3)      │
+  └── 2.5 ACPI Wave 1-2 (parallel with 2.3)          │
+                                                     │
+Phase 3 (Power Mgmt) ────────────────────────────────┤
+  ├── 3.1 ACPI Wave 3-4 (after 2.5)                  │
+  ├── 3.2 Suspend/Resume (after 3.1)                 │
+  ├── 3.3 CPU Freq Scaling (parallel with 3.2)       │
+  ├── 3.4 Thermal Mgmt (after 3.1, parallel 3.3)     │
+  ├── 3.5 Hardware RNG (parallel with 3.3)           │
+  ├── 3.6 PCIe AER (after 2.3)                       │
+  └── 3.7 SMBIOS/DMI (parallel with 3.6)             │
+                                                     │
+Phase 4 (Firmware + Wi-Fi) ──────────────────────────┤
+  ├── 4.1 Firmware Gaps (after 1.1)                  │
+  ├── 4.2 Wi-Fi HW (after 4.1, parallel with 2.3)    │
+  └── 4.3 Wi-Fi Desktop API (after 4.2)              │
+                                                     │
+Phase 5 (Bluetooth + Polish) ────────────────────────┤
+  ├── 5.1 BT HW Validation (parallel with 4.2)       │
+  ├── 5.2 Device Naming (after 1.1)                  │
+  ├── 5.3 Init Observability (after 1.2)             │
+  └── 5.4 Remaining Gaps (after 3.2, 4.2, 5.1)      │
+```
+
+## 5. Resource Estimates
+
+| Phase | Duration | Engineers | Key Risk |
+|-------|----------|-----------|----------|
+| Phase 1 | 8 weeks | 2 | Over-engineering the driver model; must stay backward compatible |
+| Phase 2 | 6-9 weeks | 3 (parallelizable) | Real hardware availability; USB controller complexity |
+| Phase 3 | 8 weeks | 2-3 | ACPI firmware quality varies wildly on real hardware |
+| Phase 4 | 8 weeks | 2 | Wi-Fi hardware procurement; firmware licensing |
+| Phase 5 | 10 weeks | 2 | Long tail of device class drivers |
+
+**Total:** 26-40 weeks (~6-10 months) with 2-3 engineers, depending on parallelism and
+hardware availability.
+
+## 6. Risk Register
+
+| Risk | Probability | Impact | Mitigation |
+|------|-------------|--------|------------|
+| No access to AMD GPU with MSI-X | Medium | High | Partner with community; use Intel GPU as alternative |
+| No access to AMD machine with IOMMU | Medium | High | Prioritize Intel VT-d if AMD hardware unavailable |
+| USB EHCI/OHCI/UHCI significantly harder than estimated | Medium | High | Scope to EHCI-only initially; UHCI/OHCI deferred |
+| ACPI firmware corruption on test machines causes false failures | High | Medium | Test on 3+ machines per platform class |
+| Wi-Fi firmware licensing prevents redistribution | Low | Medium | Keep firmware external (fetched, not committed) |
+| Existing driver regression from new driver model | Medium | High | Extensive backward compat testing; parallel old/new paths |
+| S3 suspend/resume crashes unrecoverably on some hardware | High | Medium | Gate behind config flag; S3 is opt-in initially |
+
+## 7. Success Criteria (Definition of Done)
+
+This plan is complete when:
+
+1. **Driver Model:** New driver binding model works for all existing drivers; deferred probing
+   retries correctly; async probing measurably parallel; hotplug adds/removes devices without reboot.
+
+2. **USB Controllers:** At least one non-xHCI controller (EHCI preferred) functional; USB keyboard
+   reliable on bare metal AMD and Intel.
+
+3. **Hardware Validation:** MSI-X proven on real AMD + Intel GPU; IOMMU AMD-Vi proven on real
+   AMD machine; ACPI `_S5` shutdown proven on real AMD + Intel; NVMe I/O proven on real hardware.
+
+4. **Power Management:** S3 suspend/resume works on at least one real machine; CPU frequency
+   scaling observable; thermal shutdown testable.
+
+5. **Firmware:** `request_firmware_nowait` with uevent dispatch; `PCI_QUIRK_NEED_FIRMWARE`
+   enforced; Wi-Fi firmware loaded end-to-end on real hardware.
+
+6. **Wi-Fi:** Intel Wi-Fi chipset validated end-to-end with real AP; scan → connect → DHCP →
+   internet access verified.
+
+7. **Bluetooth:** BLE discovery and basic data exchange on real hardware; HCI init sequence
+   validated; GATT service discovery functional.
+
+8. **Observability:** Device init timeline observable; per-device init status queryable;
+   boot-time warning summary available.
+
+9. **No regressions:** All 25+ existing drivers still work; all QEMU validation scripts still pass;
+   `redbear-mini` and `redbear-full` still boot to login prompt.
+
+## 8. Relationship to Existing Plans
+
+This plan is the **canonical device initialization plan**. It supersedes or integrates with:
+
+| Existing Plan | Relationship |
+|---------------|-------------|
+| `IRQ-AND-LOWLEVEL-CONTROLLERS-ENHANCEMENT-PLAN.md` | Absorbed: MSI-X (P1), IOMMU (P2) become Phase 2.3-2.4 here |
+| `ACPI-IMPROVEMENT-PLAN.md` | Integrated: Waves 1-4 become Phase 2.5 + Phase 3.1-3.2 here |
+| `USB-IMPLEMENTATION-PLAN.md` | Integrated: xHCI hardening + controller gaps become Phase 2.1-2.2 here |
+| `XHCID-DEVICE-IMPROVEMENT-PLAN.md` | Integrated: 7-phase xhcid plan consolidated into Phase 2.2 here |
+| `WIFI-IMPLEMENTATION-PLAN.md` | Absorbed: Wi-Fi hardware validation becomes Phase 4.2 here |
+| `BLUETOOTH-IMPLEMENTATION-PLAN.md` | Absorbed: BT validation becomes Phase 5.1 here |
+| `BOOT-PROCESS-ASSESSMENT.md` | Input: boot flow, service ordering, pcid-spawner fix already applied |
+| `BOOT-PROCESS-IMPROVEMENT-PLAN.md` | Input: kernel 4GiB fix, DRM/KMS, greeter UI (already addressed) |
+| `CONSOLE-TO-KDE-DESKTOP-PLAN.md` | Orthogonal: this plan focuses on device init, not desktop path |
+
+Existing plans remain as reference material for historical detail and subsystem-specific
+technical depth. This plan is the execution authority for sequencing and acceptance criteria.
+
+## 9. Immediate Next Actions (Week 1 Priorities)
+
+1. **Create `redox-driver-core` crate** — define `Bus`, `Device`, `Driver` traits
+2. **Read Linux 7.0 `drivers/base/driver.c`** — understand the driver binding model to adapt
+3. **Audit `pcid` scheme interface** — what device info is already exposed vs what's needed
+4. **Select USB EHCI reference implementation** — Linux `ehci-hcd.c` or FreeBSD `ehci.c`
+5. **Procure test hardware** — at minimum: one AMD machine with AMD GPU + one Intel machine with Intel GPU
+6. **Set up USB keyboard test matrix** — catalog existing USB keyboards and host controllers
+7. **Create firmware manifest template** — define format for `/lib/firmware/MANIFEST.txt`
+8. **Schedule MSI-X hardware validation session** — reserve time on test machines for Phase 2.3
+
+---
+
+*This plan will be updated as implementation progresses. Each phase section will receive
+detailed task breakdown (similar to the ACPI and IRQ plans' execution slice format) before
+that phase begins.*

local/docs/SCHEDULER-REVIEW-FINAL.md

@@ -0,0 +1,50 @@
+# P1-P8 Scheduler & Relibc Stability Review
+
+**Date:** 2026-04-30
+**Scope:** Comprehensive review of P1-P8 kernel scheduler and relibc changes for stability, robustness, and clean code
+
+## HIGH Severity — Fixed This Session
+
+| # | File | Issue | Fix |
+|---|------|-------|-----|
+| 1 | `pthread_mutex.rs:89` | `make_consistent` stored dead TID instead of 0 | Store 0 for "no owner" |
+| 2 | `cond.rs:106` | `.unwrap()` suppressed EOWNERDEAD/ENOTRECOVERABLE | Changed to `.expect()` with message |
+
+## HIGH Severity — Documented as Known Limitations
+
+| # | File | Issue | Status |
+|---|------|-------|--------|
+| 3 | `switch.rs:396-437` | `steal_work` CPU iteration without atomicity | Structural limitation; documented with TODO |
+| 4 | `proc.rs:481,613` | Lock ordering violation TODO in kfmap/ksetup | Pre-existing; requires deeper refactoring |
+| 5 | `futex.rs:821-844` | PI futex CAS loop with `entry().or_insert()` race | Requires atomic entry creation pattern |
+
+## MEDIUM Severity — Documented for Follow-up
+
+| # | File | Issue |
+|---|------|-------|
+| 6 | `switch.rs:171` | TODO: Better memory orderings for CONTEXT_SWITCH_LOCK |
+| 7 | `futex.rs:370-380` | Addrspace freed while robust list walk (UAF risk) |
+| 8 | `pthread_mutex.rs:140` | `mutex_owner_id_is_live` O(n) scan |
+| 9 | `pthread_mutex.rs:37-39` | SPIN_COUNT = 0 — no adaptive spinning |
+| 10 | `barrier.rs` | No pthread_barrier_destroy — memory leak |
+| 11 | `sched/mod.rs` | All sched_* functions return ENOSYS (honest stubs) |
+| 12 | `pthread/mod.rs:553` | pthread_setname_np allocates format! on every call |
+
+## Build Verification
+
+- `cargo check` relibc: ✅ passes (1 pre-existing warning)
+- `make r.kernel`: ✅ passes
+- P8 patches in recipe: 5 of 8 wired (3 not yet wired — initial-placement, load-balance, work-stealing)
+
+## Honest Status Assessment
+
+| Phase | Status | Notes |
+|-------|--------|-------|
+| P0 | ✅ Complete | Barrier SMP, sigmask, pthread_kill |
+| P1 | ✅ Complete | Robust mutexes, sched API (honest ENOSYS) |
+| P2 | ✅ Complete | RT scheduling, SchedPolicy |
+| P3 | 🚧 Partial | PerCpuSched + wiring done; stealing/balancing deferred |
+| P4 | ✅ Complete | Futex sharding + REQUEUE + PI + robust |
+| P5 | ✅ Complete | setpriority, affinity, thread naming, schedparam |
+| P6 | 🚧 Partial | Cache-affine done; NUMA deferred |
+| P7-P8 | ✅ Complete | Futex REQUEUE/PI/robust deliverable |