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>

arch/mesa-panvk-bifrost/PKGBUILD

@@ -0,0 +1,156 @@
+# Maintainer: Markus Fritsche <fritsche.markus@gmail.com>
+#
+# mesa-panvk-bifrost — patched Mesa libvulkan_panfrost.so that exposes
+# Bifrost-gen Mali (Mali-G31/G52/G72/G76, PAN_ARCH 6/7) to Chromium-family
+# browsers' Vulkan compositor.
+#
+# Campaign: ~/src/panvk-bifrost/ — iter9 close (technical milestone
+# 2026-05-20, operator-confirmed Brave window). Goal close requires
+# this package built + published + installable per the
+# feedback_package_done_means_installable.md 3-point check.
+#
+# What it does:
+#   - Builds Mesa 26.0.6 (matching ohm's stock mesa pkg) with two
+#     patches against src/panfrost/vulkan/panvk_vX_physical_device.c:
+#     (1) expose VK_KHR/EXT_robustness2 + nullDescriptor on PAN_ARCH 6/7
+#     (2) set has_vk1_1/has_vk1_2 to true on Bifrost
+#   - Installs the patched libvulkan_panfrost.so to /usr/lib/panvk-bifrost/
+#     (NOT /usr/lib — co-installs alongside stock mesa).
+#   - Registers a custom ICD JSON at a non-default path so the system
+#     Vulkan loader only picks up our driver when VK_ICD_FILENAMES is set.
+#   - Ships /usr/bin/brave-vulkan launcher that wires up env vars + flags.
+#
+# Co-existence: stock /usr/lib/libvulkan_panfrost.so is untouched. Stock
+# /usr/share/vulkan/icd.d/panfrost_icd.json is untouched. Users opt in
+# via brave-vulkan (or by setting VK_ICD_FILENAMES manually).
+#
+# Build target: arch-aarch64 runner via marfrit-packages Gitea Actions.
+# Mesa build is slow (~30-60min on Cortex-A55). Build deps installed
+# inside the runner via pacman -S in the workflow.
+
+pkgname=mesa-panvk-bifrost
+_mesaver=26.0.6
+pkgver=26.0.6.r2
+pkgrel=1
+pkgdesc="Patched Mesa libvulkan_panfrost.so exposing Bifrost-gen Mali to Vulkan apps (panvk-bifrost campaign)"
+arch=('aarch64')
+url="https://github.com/marfrit/panvk-bifrost"
+license=('MIT')
+
+# We co-install at /usr/lib/panvk-bifrost/ so no conflicts with stock mesa.
+# We DO provide a script that requires brave to be installed.
+depends=(
+    'mesa'              # for shared mesa runtime libs (libgallium-mesa etc.)
+    'libdrm'
+    'wayland'
+    'libxcb'
+    'libx11'
+    'libxshmfence'
+    'zlib'
+    'zstd'
+    'libdisplay-info'
+    'expat'
+    'systemd-libs'      # libudev
+    'spirv-tools'
+)
+optdepends=(
+    'brave-bin: for the brave-vulkan launcher script'
+)
+makedepends=(
+    'meson'
+    'ninja'
+    'pkgconf'
+    'bison'
+    'flex'
+    'python'
+    'python-yaml'
+    'python-mako'
+    'glslang'
+    'spirv-tools'
+    'llvm'
+    'clang'
+    'libclc'
+    'spirv-llvm-translator'
+    'vulkan-headers'
+    'wayland-protocols'
+)
+
+source=(
+    "https://archive.mesa3d.org/mesa-${_mesaver}.tar.xz"
+    "0001-panvk-expose-robustness2-nullDescriptor-bifrost.patch"
+    "0002-panvk-expose-vulkan-1.1-1.2-on-bifrost.patch"
+    "brave-vulkan"
+    "icd.json"
+)
+sha256sums=(
+    'SKIP'  # TODO: pin once we know the upstream tarball is stable. archive.mesa3d.org tarballs are stable, so we can hash-pin in iter10.
+    'SKIP'
+    'SKIP'
+    'SKIP'
+    'SKIP'
+)
+
+prepare() {
+    cd "mesa-${_mesaver}"
+    # iter8 patch: robustness2 + nullDescriptor exposure on Bifrost.
+    # Three hunks in panvk_vX_physical_device.c. Apply via sed since
+    # the upstream context drifts between Mesa releases and unified-diff
+    # patching is brittle (we hit hunk-rejects during manual application).
+    sed -i 's|\.KHR_robustness2 = PAN_ARCH >= 10,|.KHR_robustness2 = true,|' src/panfrost/vulkan/panvk_vX_physical_device.c
+    sed -i 's|\.EXT_robustness2 = PAN_ARCH >= 10,|.EXT_robustness2 = true,|' src/panfrost/vulkan/panvk_vX_physical_device.c
+    sed -i 's|\.nullDescriptor = PAN_ARCH >= 10,|.nullDescriptor = true,|' src/panfrost/vulkan/panvk_vX_physical_device.c
+    # iter9 patch: bump api version to 1.1/1.2 for Bifrost. NOTE: this only
+    # affects extension exposure flags, NOT the reported apiVersion (which
+    # is set by get_api_version() further down and gated separately).
+    # The brave-vulkan launcher sets MESA_VK_VERSION_OVERRIDE=1.2 at runtime
+    # to deal with the latter — no source change needed for that path.
+    sed -i 's|bool has_vk1_1 = PAN_ARCH >= 10;|bool has_vk1_1 = true;|' src/panfrost/vulkan/panvk_vX_physical_device.c
+    sed -i 's|bool has_vk1_2 = PAN_ARCH >= 10;|bool has_vk1_2 = true;|' src/panfrost/vulkan/panvk_vX_physical_device.c
+
+    # Sanity-check the patches landed.
+    grep -q "KHR_robustness2 = true," src/panfrost/vulkan/panvk_vX_physical_device.c
+    grep -q "EXT_robustness2 = true," src/panfrost/vulkan/panvk_vX_physical_device.c
+    grep -q "nullDescriptor = true," src/panfrost/vulkan/panvk_vX_physical_device.c
+    grep -q "has_vk1_1 = true;" src/panfrost/vulkan/panvk_vX_physical_device.c
+    grep -q "has_vk1_2 = true;" src/panfrost/vulkan/panvk_vX_physical_device.c
+}
+
+build() {
+    cd "mesa-${_mesaver}"
+    # Minimal Mesa build — only the panvk Vulkan driver. No GLES/GLX/EGL/
+    # gallium drivers — keeps the build narrower and avoids pulling in
+    # the entire Mesa runtime in this package's dep graph.
+    meson setup build/ \
+        --prefix=/usr \
+        --libdir=lib \
+        --buildtype=release \
+        -Dvulkan-drivers=panfrost \
+        -Dgallium-drivers= \
+        -Dplatforms=wayland,x11 \
+        -Dglx=disabled \
+        -Degl=disabled \
+        -Dgles1=disabled \
+        -Dgles2=disabled \
+        -Dvulkan-layers= \
+        -Dtools= \
+        -Dgallium-rusticl=false \
+        -Dmicrosoft-clc=disabled
+    meson compile -C build
+}
+
+package() {
+    cd "${srcdir}/mesa-${_mesaver}"
+
+    # Patched lib — co-install path, NOT /usr/lib (to avoid clashing
+    # with stock mesa's libvulkan_panfrost.so).
+    install -Dm755 build/src/panfrost/vulkan/libvulkan_panfrost.so \
+        "$pkgdir/usr/lib/panvk-bifrost/libvulkan_panfrost.so"
+
+    # Custom ICD JSON. NOT under /usr/share/vulkan/icd.d/ (the default
+    # loader search path) — the user has to opt in via VK_ICD_FILENAMES.
+    install -Dm644 "$srcdir/icd.json" \
+        "$pkgdir/usr/lib/panvk-bifrost/icd.json"
+
+    # The brave-vulkan launcher wires up env + flags.
+    install -Dm755 "$srcdir/brave-vulkan" "$pkgdir/usr/bin/brave-vulkan"
+}