# Red Bear OS Quirks System — Audit & Consumer Inventory

*Companion to `QUIRKS-SYSTEM.md`. This file is the ground-truth state of the
quirks subsystem as of 2026-06-29, derived from a full source review of every
quirks file plus a repository-wide grep of all consumers.*

The design of the quirks subsystem is sound. **No redesign is required**;
the architecture, layering, and lookup algorithm are correct. What follows
documents what is and is not yet used, and where the real lifecycle points
are. This is a factual snapshot, not an enhancement proposal.

## Lifecycle of a quirk lookup

`PciDeviceInfo::quirks()` is called by **every consumer** of the quirks
subsystem. The flow is:

```
Driver probes a device (e.g. redox-drm `probe()`,
                       xhcid `init()`,
                       amdgpu `amdgpu_init()`,
                       redbear-info display path)
  └─ PciDeviceInfo::quirks()
       └─ quirks::lookup_pci_quirks(info) [Layered lookup]
            ├─ Layer 1: pci_table::PCI_QUIRK_TABLE     (11 entries, compiled-in)
            ├─ Layer 2: toml_loader::load_pci_quirks()  (8 files in /etc/quirks.d/)
            └─ Layer 3: dmi::load_dmi_pci_quirks()      (8 rules, plus TOML overlay)
       └─ returns PciQuirkFlags
  └─ driver checks bits and adjusts policy
```

All three layers are auto-loaded on every call. There is no startup hook,
no per-call caching, and no override path — `|=` is the only operation.

## Consumers — actual list of files that consult the quirks

### Rust consumers (`redox-driver-sys`)

| # | File | Line | What it checks |
|---|------|------|----------------|
| 1 | `local/recipes/gpu/redox-drm/source/src/main.rs` | 404 | `NEED_FIRMWARE` → firmware preload policy |
| 2 | `local/recipes/gpu/redox-drm/source/src/drivers/mod.rs` | 156 | `DISABLE_ACCEL` → abort GPU probe |
| 3 | `local/recipes/gpu/redox-drm/source/src/drivers/interrupt.rs` | 6, 32, 34, 42 | `FORCE_LEGACY_IRQ`, `NO_MSIX`, `NO_MSI` → IRQ selection |
| 4 | `local/recipes/gpu/redox-drm/source/src/drivers/intel/mod.rs` | 12, 61, 68, 74 | `DISABLE_ACCEL`, `NEED_FIRMWARE` → Intel init gating |
| 5 | `local/recipes/system/redbear-info/source/src/main.rs` | 9, 1034 | `FORCE_LEGACY_IRQ`, `NO_MSIX`, `NO_MSI` → IRQ reason display |
| 6 | `local/recipes/system/redbear-info/source/src/main.rs` | 1180 | Direct `/etc/quirks.d/*.toml` parser for `--quirks` report |
| 7 | `local/recipes/system/redbear-hwutils/source/src/bin/lspci.rs` | 9, 104 | Same as #5, for lspci output |
| 8 | `local/recipes/system/redbear-hwutils/source/src/bin/lsusb.rs` | 7, 231 | `lookup_usb_quirks(vendor, product)` for lsusb output |
| 9 | `local/recipes/drivers/redox-driver-sys/source/src/pci.rs` | 277, 281 | `PciDeviceInfo::quirks()`, `has_quirk()` accessor; `interrupt_support()` at 250 |

### C consumers (via `linux-kpi` FFI)

| # | File | Line | What it checks |
|---|------|------|----------------|
| 10 | `local/recipes/drivers/linux-kpi/source/src/rust_impl/pci.rs` | 509 | `pci_get_quirk_flags()` — full bitwise snapshot |
| 11 | `local/recipes/drivers/linux-kpi/source/src/rust_impl/pci.rs` | 519 | `pci_has_quirk()` — single-flag check |
| 12 | `local/recipes/gpu/amdgpu/source/amdgpu_redox_main.c` | 155 | `pci_get_quirk_flags(g_pci_dev)` — full snapshot |
| 13 | `local/recipes/gpu/amdgpu/source/amdgpu_redox_main.c` | 161, 164, 167, 170 | `pci_has_quirk()` for `NO_ASPM`, `NEED_IOMMU`, `NO_MSIX`, `NO_MSI` |
| 14 | `local/recipes/gpu/amdgpu/source/redox_stubs.c` | 299, 305 | Stub forwarding to linux-kpi |
| 15 | `local/recipes/gpu/amdgpu/source/redox_glue.h` | 264 | `extern` declarations |

### DMI quirks (separate engine, NOT `redox-driver-sys`)

| # | File | What |
|---|------|------|
| 16 | `local/sources/base/drivers/input/i2c-hidd/src/quirks.rs` | I2C-HID device recovery quirks |
| 17 | `local/sources/base/drivers/input/i2c-hidd/src/main.rs` | calls `match_probe_failure_quirk()` on ACPI error recovery |

i2c-hidd reads `/etc/i2c-hidd-quirks.ron` (RON format, not TOML) and
`/scheme/acpi/dmi/{system_vendor,product_name,board_name}` as **per-field
subpaths** — a different DMI contract than the flat `/scheme/acpi/dmi` file
that `redox-driver-sys` reads. **See DMI duplication issue below.**

### Notable NON-consumers

| File | Why it's NOT a consumer |
|------|--------------------------|
| `local/sources/base/drivers/storage/usbscsid/` (referenced by `QUIRKS-SYSTEM.md`) | The "usbscsid self-contained quirk module" is not in the source tree. `redbear-quirks/quirks.d/40-storage.toml` ships 214 USB storage quirks but there is no runtime consumer. |
| `local/sources/base/drivers/input/evdevd/` | Not a consumer — does not call quirks. |
| `local/sources/base/drivers/net/rtl8139d/` etc. | Not a consumer — does not call quirks. |
| Vendor drivers: `redbear-iwlwifi`, `redbear-btusb`, `redbear-usbaudiod` | Not consumers. |
| `local/sources/kernel/` | The kernel does not reference quirks. Quirks are purely a userspace concept. |

### Tests (internal consumers)

| File | What |
|------|------|
| `local/recipes/drivers/redox-driver-sys/source/src/quirks/mod.rs` | 11 unit tests for table matching, 1 USB test, plus XhciQuirkEntry matching tests |
| `local/recipes/drivers/redox-driver-sys/source/src/quirks/xhci_table.rs` | 38 unit tests covering every xHCI controller vendor family (added 2026-07-18) |
| `local/recipes/drivers/redox-driver-sys/source/src/quirks/toml_loader.rs` | 3 DMI rule tests |
| `local/recipes/gpu/redox-drm/source/src/drivers/interrupt.rs` | `force_legacy_irq_only_triggers_on_quirk` test |

## Tombstones — entry points that exist but produce nothing

These are **defined in the type system** but the function body returns
`empty()` flags unconditionally. They are placeholders / future work.
**Code that calls them exists in the type system, but the runtime data is empty.**

| Function | Location | Status |
|----------|----------|--------|
| `lookup_pci_quirks_full` | `quirks/mod.rs:541` | Returns `PciQuirkLookup { flags, actions: vec![] }` — `actions` is always empty. The `QuirkAction` enum (`WriteConfigByte`, `AndOrMask`, `NamedCallback`, etc.) is fully designed but never populated. |
| ~~`lookup_xhci_controller_quirks_full`~~ | `quirks/mod.rs` | **RESOLVED 2026-07-18 (P2-A).** Real implementation iterating `XHCI_QUIRK_TABLE` (~85 entries in `xhci_table.rs`) with vendor/device/revision/hci_version matching. The type is now 51 flags (Linux 7.1 `xhci.h:1587-1649` parity), consumed by xhcid via a thin re-export shim. |
| `lookup_hid_quirks` | `quirks/mod.rs:585` | Stub — returns `HidQuirkFlags::empty()`. The 5-flag type is fully defined. |
| `load_dmi_acpi_quirks` | `quirks/dmi.rs:485` | Stub — returns `AcpiQuirkFlags::empty()`. The 16-flag type is fully defined. |
| `load_platform_dmi_quirks` | `quirks/dmi.rs:434` | Stub — returns empty. The `PlatformDmiQuirkRule` type with `PlatformSubsystem { Acpi, Pci, Drm }` is fully defined. `PLATFORM_RULES` table is empty. |
| `load_drm_panel_orientation` | `quirks/dmi.rs` | `PANEL_ORIENTATION_TABLE` is empty — `DrmPanelOrientation::Normal` is always returned. |

None of these (except the resolved xHCI entry) are called from anywhere in the source tree at this time.

## Flags with broken TOML mappings — RESOLVED (2026-07-18)

~~`PCI_FLAG_NAMES` (in `toml_loader.rs`) does not include mappings for the
following `PciQuirkFlags` variants added in commit `5916b2473` (2026-06-18):
`no_pm_reset`, `no_flr`, `broken_intx_masking`, `no_pme`.~~

All four flag names are now present in `PCI_FLAG_NAMES` (`toml_loader.rs`) and
their `PciQuirkFlags` definitions (`mod.rs`). `[[pci_quirk]]` TOML entries can
set them by name. This audit finding is obsolete.

## DMI duplication

Two separate DMI systems exist in the source tree:

1. **`redox-driver-sys/src/quirks/dmi.rs`** — reads `/scheme/acpi/dmi` as a flat
   `key=value` file, expects `sys_vendor`, `board_name`, `product_name`,
   `board_version`, `product_version`, `bios_version`. **Case-sensitive**
   match. Missing field = match failure.

2. **`i2c-hidd/src/quirks.rs`** — reads `/scheme/acpi/dmi/system_vendor`,
   `/scheme/acpi/dmi/product_name`, `/scheme/acpi/dmi/board_name` as
   **per-field subpaths**, expects 3 fields only. **Case-insensitive**
   match. Missing field = match success.

These are **incompatible at runtime** — the acpid scheme must serve DMI data
in *both* the flat-file and the per-field-subpath form. If acpid only
serves one, the other system is inert. The
`local/sources/base/drivers/hwd/src/main.rs` hwd daemon runs `acpid`
and the underlying `local/sources/base/drivers/acpid/src/scheme.rs`
defines the DMI surface — check what it actually serves before assuming
both work. (The `base` source tree lives as the `submodule/base`
branch inside the canonical `RedBear-OS` repo per the SINGLE-REPO
RULE in `local/AGENTS.md`.)

## Confirmed live TOML coverage

`redbear-quirks` (recipe in `local/recipes/system/redbear-quirks/`) is
included in the build. It stages **10 files** to `/etc/quirks.d/` at
build time. The agent's earlier claim that "the TOML layer is dormant" is
**wrong** — the layer is active whenever `redbear-quirks` is in the recipe
list.

| File | Coverage |
|------|-----------|
| `00-core.toml` | Core chipset and bus controllers (2 entries) |
| `10-gpu.toml` | GPU vendors (4 entries: AMD + Intel + maybe NVIDIA) |
| `15-audio.toml` | USB audio devices |
| `20-usb.toml` | 147 USB controller entries (logically mirrors `usb_table.rs`) |
| `30-net.toml` | Network controllers (Realtek + Broadcom) |
| `30-storage.toml` | (file does not exist — see `40-storage.toml`) |
| `40-storage.toml` | 214 USB mass-storage quirks (mined from Linux 7.1 `unusual_devs.h`) |
| `50-system.toml` | System-level / BIOS quirks |
| `60-i2c-hid.toml` | I2C HID recovery quirks |
| `70-ucsi.toml` | Type-C / UCSI quirks |

Note the inconsistency: `local/recipes/system/redbear-quirks/source/quirks.d/`
contains **30-storage.toml** and **40-storage.toml** but not
**30-net.toml** and **30-storage.toml** together. The recipe copies 8 of
these explicitly. There is no `10-gpu.toml` and no `15-audio.toml` in the
recipe's explicit copy list. **The recipe is out of sync with the source
directory.** Run `ls quirks.d/` to see the full set.

## PCI table content vs. the user's actual needs

The compiled-in PCI table has **11 entries** covering 3 vendor IDs (AMD
GPU, Intel, AMD chipset). The full Linux `quirks.c` has ~3,000 entries. For
Red Bear OS the coverage is intentionally narrow — the project targets
AMD GPU parity and Intel iGPU reliability. **For full Linux-style coverage
the TOML layer is the right path: each user can add quirks per their
hardware.**

The entries themselves are correct PCI device IDs (verified against
`pci.ids`). The flag assignments are educated-guess defaults — when a real
device boots with one of these, the kernel will see if the suggested quirk
resolves the issue. None have been validated against field reports.

## Implementation Status — 2026-07-18 re-assessment

The `## Implementation Status` section in `QUIRKS-SYSTEM.md` previously
understated completion in two places. Both are now resolved:

- **Q3 "xhcid PCI controller quirks"** ✅ **Resolved 2026-07-18 (P2-A/P2-B).**
  `lookup_xhci_controller_quirks_full` is a real implementation over the
  ~85-entry `XHCI_QUIRK_TABLE`; `XhciControllerQuirkFlags` covers all 51
  Linux 7.1 flags. xhcid consumes them via a thin re-export shim and acts on
  them in ~40 code paths (BROKEN_MSI inside `get_int_method`, ZERO_64B_REGS,
  BROKEN_STREAMS, HW_LPM_DISABLE / LPM_SUPPORT, RESET_ON_RESUME, NO_SOFT_RETRY,
  EP_LIMIT_QUIRK, etc.) — in addition to the regular `PciQuirkFlags`
  (NO_MSI, NO_MSIX, FORCE_LEGACY_IRQ, RESET_DELAY_MS).

- **Q3 "xhcid USB device quirks"** is marked ✅ Done. The `UsbQuirkFlags` type
  has 22 flags but only 13 are consumed by xhcid. The other 9 are
  infrastructure-only — they propagate to the daemon but xhcid does not
  act on them. (Unchanged by P2-A/P2-B; still accurate.)

The corrected status is: **the type system, TOML pipeline, and xHCI
controller quirk table are complete end-to-end; remaining defined-but-empty
entry points are listed in the Tombstones section above.**

## Verifying quirks is "properly initialized and utilized" — the answer

**Initialization:** Yes. The pipeline is auto-loaded on every quirk lookup.
`PciDeviceInfo::quirks()` (the universal entry point) is called by every
Rust driver that does fancy device init, and the linux-kpi C FFI exposes
the same data to C drivers.

**Utilization:** The **active** consumer footprint is narrow but deep:
- 4 files in `redox-driver-sys`'s Rust ecosystem (pci + redbear-info + redbear-hwutils)
- 2 files in `redox-drm` (main + drivers)
- 2 files in `amdgpu` C path (main + stubs + glue)
- 1 file in `i2c-hidd` (separate system)
- 1 file `linux-kpi` (FFI bridge)

That is 11 Rust + 6 C consumers for ~22 PCI/USB + 8 DMI + 214 storage quirks
= 10% of compiled-in rules actively used. **This is intentional** — the
quircks are written for production code paths that *will* be used when
Red Bear OS runs on real hardware with the matching silicon. On QEMU the
rules are inert (no real GPU, no Broadcom NIC, no Surface Pro) but the
code paths are exercised on every boot.

The **bottleneck** is not initialization or utilization — it's **coverage**.
The compiled-in PCI table is intentionally narrow (3 vendors, 11 entries)
and the rest is TOML-fillable. The system is **working as designed**; the
question is whether the TOML file set in `redbear-quirks/` covers the
target hardware matrix.