mesa-panvk-bifrost: new package — Vulkan-compositor Brave for Bifrost SBCs

iter9 of the panvk-bifrost campaign — operator-confirmed Vulkan output
on PineTab2 (Mali-G52 r1 MC1) 2026-05-20.

Patches Mesa 26.0.6's PanVk Vulkan driver:
  - VK_KHR/EXT_robustness2 + nullDescriptor exposed for PAN_ARCH 6/7
  - has_vk1_1 / has_vk1_2 = true on Bifrost
Patches applied via sed in PKGBUILD prepare() (cleaner than maintaining
a Mesa fork for two two-line tweaks; upstream context drifts between
Mesa releases would make a literal .patch brittle).

Co-installs at /usr/lib/panvk-bifrost/ — stock mesa untouched. Stock
libvulkan_panfrost.so and its ICD JSON keep working for everyone not
opting into the patched driver.

Ships /usr/bin/brave-vulkan that wires up:
  VK_ICD_FILENAMES=/usr/lib/panvk-bifrost/icd.json
  PAN_I_WANT_A_BROKEN_VULKAN_DRIVER=1
  MESA_VK_VERSION_OVERRIDE=1.2     # ANGLE needs apiVersion>=1.1; the
                                   # has_vk1_x flags don't move it, so
                                   # the env-var override carries that
  brave --use-gl=disabled --enable-features=Vulkan --use-vulkan=native
        --ozone-platform=x11 --no-sandbox --disable-gpu-sandbox
        --ignore-gpu-blocklist "$@"

Side-steps the stock "GLES3 is unsupported / GPU process exits" failure
documented in panvk-bifrost/README's "Consumer-side benefit" section.

Known limitation: WebGL/WebGL2 in-page won't work — ANGLE needs GLES3
which needs VK_EXT_transform_feedback, which PanVk-Bifrost doesn't
currently support. Browser chrome + standard page rendering work fine.

Gitea Actions job mesa-panvk-bifrost-aarch64 added to build.yml,
patterned on libva-v4l2-request-fourier-aarch64. Mesa build is slow
(~30-60min on actrunner-aarch64). Standalone (no needs:),
continue-on-error so it doesn't block other jobs.

Campaign artifacts: ~/src/panvk-bifrost/{README.md, phase8_iteration9_close.md,
phase0_evidence/iter9_brave_vulkan_breakthrough.txt}.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

.gitea/workflows/build.yml

@@ -1092,3 +1092,121 @@ jobs:
       - name: wipe secrets
         if: always()
         run: rm -f /root/.ssh/id_ed25519_hertz
+
+  # -------------------------------------------------------------------------
+  # mesa-panvk-bifrost (aarch64 only) — patched Mesa libvulkan_panfrost.so
+  # for Bifrost-gen Mali (panvk-bifrost campaign iter9). Co-installs at
+  # /usr/lib/panvk-bifrost/ so stock mesa stays intact; opt-in via the
+  # brave-vulkan launcher this package also ships.
+  #
+  # Build is slow (~30-60min on actrunner-aarch64): full Mesa-from-source.
+  # Standalone job — no `needs:` since it doesn't depend on the fourier
+  # codec stack. continue-on-error so a build hiccup doesn't block other
+  # jobs in the same workflow run.
+  # -------------------------------------------------------------------------
+  mesa-panvk-bifrost-aarch64:
+    runs-on: arch-aarch64
+    continue-on-error: true
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: bootstrap runner (idempotent)
+        run: |
+          set -e
+          retry() { for i in 1 2 3; do "$@" && return 0; rc=$?; echo "retry $i (exit=$rc)" >&2; sleep $((i*5)); done; return 1; }
+          retry pacman -Syu --noconfirm --needed base-devel git rsync gnupg openssh sudo
+
+      - name: import signing key
+        env:
+          PRIV: ${{ secrets.MARFRIT_REPO_PRIVATE_KEY }}
+          PASS: ${{ secrets.MARFRIT_REPO_PASSPHRASE }}
+        run: |
+          set -e
+          gpgconf --homedir /root/.gnupg --kill all 2>/dev/null || true
+          rm -rf /root/.gnupg /root/repo_pass
+          mkdir -m700 -p /root/.gnupg
+          printf '%s' "$PASS" > /root/repo_pass
+          chmod 600 /root/repo_pass
+          printf '%s\n' "$PRIV" | gpg --batch --import
+          echo "92D5E96D8F63C75E4116AA1FF5C8C4603D0D250C:6:" | gpg --import-ownertrust
+
+      - name: install deploy ssh key
+        env:
+          KEY: ${{ secrets.MARFRIT_REPO_DEPLOY_KEY }}
+        run: |
+          mkdir -m700 -p /root/.ssh
+          printf '%s\n' "$KEY" > /root/.ssh/id_ed25519
+          chmod 600 /root/.ssh/id_ed25519
+          ssh-keyscan -t ed25519 nc.reauktion.de > /root/.ssh/known_hosts 2>/dev/null
+
+      - name: makepkg mesa-panvk-bifrost
+        run: |
+          set -e
+          rm -rf /tmp/build-mesa-panvk-bifrost
+          cp -r arch/mesa-panvk-bifrost /tmp/build-mesa-panvk-bifrost
+          chown -R builder:builder /tmp/build-mesa-panvk-bifrost
+          cd /tmp/build-mesa-panvk-bifrost
+          # MAKEFLAGS for parallel build; runner is multi-core.
+          # --skipinteg because sha256sums=SKIP in PKGBUILD (matches the
+          # fourier-fork PKGBUILD convention).
+          sudo -u builder -H env MAKEFLAGS="-j60" \
+            makepkg --nocheck --noconfirm --syncdeps --cleanbuild --skipinteg
+          ls -la *.pkg.tar.* | grep -v "\.sig$"
+
+      - name: sign mesa-panvk-bifrost
+        run: |
+          set -e
+          cd /tmp/build-mesa-panvk-bifrost
+          for f in *.pkg.tar.xz *.pkg.tar.zst *.pkg.tar.gz; do
+            [ -f "$f" ] || continue
+            gpg --batch --pinentry-mode loopback --passphrase-file /root/repo_pass \
+                --detach-sign --yes -u 92D5E96D8F63C75E4116AA1FF5C8C4603D0D250C "$f"
+          done
+
+      - name: update aarch64 repo db
+        run: |
+          set -e
+          mkdir -p /tmp/arch-stage-mesa-panvk
+          cd /tmp/arch-stage-mesa-panvk
+          rm -f *
+          for f in marfrit.db.tar.gz marfrit.db.tar.gz.sig marfrit.files.tar.gz marfrit.files.tar.gz.sig; do
+            curl -sSLf "https://packages.reauktion.de/arch/aarch64/$f" -o "$f" || rm -f "$f"
+          done
+          for ext in xz zst gz; do
+            ls /tmp/build-mesa-panvk-bifrost/*.pkg.tar.$ext 2>/dev/null && \
+              mv /tmp/build-mesa-panvk-bifrost/*.pkg.tar.$ext /tmp/build-mesa-panvk-bifrost/*.pkg.tar.$ext.sig .
+          done || true
+          export GNUPGHOME=/root/.gnupg
+          printf 'pinentry-mode loopback\npassphrase-file /root/repo_pass\n' > /root/.gnupg/gpg.conf
+          printf 'allow-loopback-pinentry\n' > /root/.gnupg/gpg-agent.conf
+          gpg-connect-agent reloadagent /bye
+          pkgs=()
+          for ext in xz zst gz; do
+            for f in *.pkg.tar.$ext; do [ -f "$f" ] && pkgs+=("$f"); done
+          done
+          if [ -f marfrit.db.tar.gz ]; then
+            for f in "${pkgs[@]}"; do
+              name=$(echo "$f" | sed -E 's/-[0-9].*//')
+              repo-remove --sign --key 92D5E96D8F63C75E4116AA1FF5C8C4603D0D250C \
+                marfrit.db.tar.gz "$name" 2>/dev/null || true
+            done
+          fi
+          repo-add --new --sign --key 92D5E96D8F63C75E4116AA1FF5C8C4603D0D250C \
+            --verify marfrit.db.tar.gz "${pkgs[@]}"
+          ln -sf marfrit.db.tar.gz        marfrit.db
+          ln -sf marfrit.files.tar.gz     marfrit.files
+          ln -sf marfrit.db.tar.gz.sig    marfrit.db.sig
+          rm -f marfrit.files.sig
+
+      - name: publish to aarch64
+        run: |
+          set -e
+          retry() { for i in 1 2 3; do "$@" && return 0; rc=$?; echo "retry $i (exit=$rc)" >&2; sleep $((i*5)); done; return 1; }
+          cd /tmp/arch-stage-mesa-panvk
+          retry rsync -avL --copy-unsafe-links \
+            -e 'ssh -i /root/.ssh/id_ed25519' \
+            ./ mfritsche@nc.reauktion.de:arch/aarch64/
+
+      - name: wipe secrets
+        if: always()
+        run: rm -f /root/repo_pass /root/.ssh/id_ed25519