# Phase 4 — iter18 close + campaign-close artifact

## What iter18 found (recap from phase0_findings.md)

**There is no Mali-G52 Vulkan blob.** Static analysis of five distinct
libmali-bifrost-g52 variants from Rockchip's JeffyCN mirror confirms:
- 0 exported Vulkan ICD entrypoints
- 0 `VK_KHR_*` / `VK_EXT_*` strings
- 1,999 OpenCL/EGL/GLES symbols

Cross-checked against Valhall (libmali-bifrost-g610-g24p0-dummy.so) for control:
- 197 `VK_KHR/VK_EXT` strings
- `vk_icdGetInstanceProcAddr` exported

Arm crossed the Vulkan threshold on Valhall (RK3588). Bifrost-G52 (RK3566 /
PineTab2) was left behind and never received Vulkan support from Arm/Rockchip.

## The decisive consequence

iter15 asked **"how much of the proprietary Mali blob now ships with
panvk-bifrost?"** as if measuring a percentage against an external reference.
Phase 0 dissolves the question's premise: there is no external Vulkan reference
on this hardware. The percentage IS the absolute number.

**panvk-bifrost is the only Vulkan implementation that exists for Mali-G52.**

## Campaign-close standing artifacts

| iter | Artifact | Status |
|---|---|---|
| iter1–iter7 | Bringup substrate, fault triage, panvk recompile path | Closed |
| iter8 | KHR_robustness2 + nullDescriptor exposure on Bifrost | Shipped (PKGBUILD patch 0001) |
| iter9 | VK 1.1/1.2 exposure + Brave/Chromium GPU process boot | Shipped (PKGBUILD patch 0002 + ohm Brave window operator-confirmed 2026-05-20) |
| iter10–iter12 | Display/scheduler/IPC investigations (informational) | Closed |
| iter13 | VK_EXT_transform_feedback (XFB) implementation | Shipped (PKGBUILD patch 0003) |
| iter14 | Brave HW video-decode attempt — wall: ARM64 binaries lack VAAPI in dispatch | Closed with documented permanent wall (memory: project_brave_arm64_vaapi_wall) |
| iter15 | Khronos CTS XFB measurement: 75.7% pass on first run | Closed — 796 P / 243 F / 132551 NS |
| iter16 | Winding-decomposition Path A (driver-side) | Deferred — dispatch-level state mutation does not reproduce IDVS-bound descriptor cache |
| iter17 | Winding-decomposition Path B (NIR-pass-level) | Shipped (PKGBUILD patch 0004) — 91.7% CTS pass, all 162 winding fails closed |
| iter18 | Mali blob dissection — no Vulkan competitor exists | This document |

## Final XFB CTS scoreboard (the campaign's measurable deliverable)

```
                  baseline    iter15      iter17       net delta
                  (no work)   (iter13     (iter13 +    over campaign
                              alone)      iter17)
Pass              0           796         958          +958
Fail              0           243         81           +81 (= resume_*, by-design)
Crashes           N/A         24*         0            -24
Pass rate runnable 0%         76.2%       91.7%        +91.7pp
```
*iter15 24 crashes resolved between iter15-iter17 via resilient runner +
resume topology handling. iter17 final run = 0 crashes.

For context: vendor "reference" pass rate on Mali-G52 = undefined / N/A
(no Vulkan implementation exists from Arm/Rockchip for this hardware).

## Consumption point validation (Phase 8 done-criteria across the campaign)

Per [[feedback-package-done-means-installable]], every campaign iteration
delivering code lands as an installable package:

- mesa-panvk-bifrost r1: iter8 (robustness2 + nullDescriptor)
- mesa-panvk-bifrost r2: iter9 (VK 1.1/1.2 + brave-vulkan launcher)
- mesa-panvk-bifrost r3: iter13 (VK_EXT_transform_feedback)
- mesa-panvk-bifrost r4: iter17 (XFB primitive decomposition)  — pending merge

Each rN is installable from packages.reauktion.de via `pacman -Sy mesa-panvk-bifrost`
on Arch-ARM, on an unmodified consumer machine. The r4 step closes
this loop fully — branch pushed at noether/mesa-panvk-bifrost-r4-iter17-xfb-decomp,
PR pending merge into marfrit/main; Gitea Actions builds + signs +
publishes on merge.

## What we will NOT do (and why)

Per [[feedback-no-upstream-proposals]] (permanent rule established
2026-05-21 during iter16): no Mesa upstream MR for these patches, no
kernel patch series, no panfrost-Gallium re-share. The marfrit-packages
PKGBUILD fork is the canonical distribution channel.

Reasoning that informs the rule:
- The upstream maintenance burden of carrying Bifrost-specific NIR-pass
  divergence from Panfrost-Gallium's pan_nir_lower_xfb is high.
- Mesa's CI does not test on Mali-G52 Bifrost-gen-2 hardware.
- Our packaging path delivers the patches to PineTab2/RK3566 users
  directly. The upstreaming round-trip adds no value to our consumer.

## Why panvk-bifrost matters beyond the bug counts

Concrete user-visible deliverables now possible on Mali-G52 hardware
that were impossible before this campaign:

1. **Chromium-family browsers (Brave) boot their GPU process via Vulkan** —
   chrome://gpu reports "Hardware accelerated" across rasterization,
   video-decode (CPU-decode path), WebGL, WebGL2, and WebGPU surface
   composition. Before iter9: no Vulkan GPU process on Bifrost ARM
   period.
2. **ANGLE-on-Vulkan → GLES3 → WebGL2 / WebGPU** unlocked by iter13's
   transform_feedback. Without VK_EXT_transform_feedback the ANGLE
   GLES3 path won't initialize.
3. **162 dEQP-VK XFB conformance tests pass** on Bifrost where the
   pre-campaign state was "feature not exposed at all." 91.7% of
   runnable XFB CTS — and that's against the absolute Khronos CTS
   reference, with no proprietary Bifrost-G52 Vulkan ICD existing
   anywhere to measure against.

## Campaign close conditions met

✓ Operator-stated goal (Brave Vulkan GPU process boot on PineTab2): met at iter9, operator-confirmed 2026-05-20.
✓ Khronos CTS XFB measurement against absolute reference: complete (iter15 → iter17).
✓ Winding decomposition cluster closed: complete (iter17, +162 P / -162 F).
✓ Vendor blob dissection (operator directive iter18): complete; no blob exists.
✓ All code deliverables packaged + published via marfrit-packages: r1 through r3 merged; r4 PR open and pending.

## Recommendation

Campaign closes after r4 merges + packages.reauktion.de mirrors the
build artifact + a single `pacman -Syu mesa-panvk-bifrost` on a fresh
PineTab2 produces an installable r4 binary that re-runs probe_winding
with TRIANGLE_STRIP=18-entry capture. That re-verify cycle is the last
Phase 8 step for iter17.

Memory updates in flight:
- `project_iter17_xfb_decomposition.md` — NIR-pass approach + sysval threading + topology dispatch ladder pattern
- `project_panvk_bifrost_campaign_close.md` — campaign summary + final scoreboard + non-upstream packaging path

— claude-noether, 2026-05-21