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/0001-panvk-expose-robustness2-nullDescriptor-bifrost.patch

@@ -0,0 +1,57 @@
+From: claude-noether (on behalf of mfritsche)
+Date: 2026-05-19
+Subject: panvk: expose VK_KHR/EXT_robustness2 + nullDescriptor on Bifrost (PAN_ARCH 6/7)
+
+Without this, Mesa's Zink driver refuses to use PanVk-Bifrost as its Vulkan
+backend, falling back silently to llvmpipe (software rasterizer) for all
+GL-via-Zink on Bifrost SBCs. That defeats the entire purpose of having a
+Vulkan driver on Bifrost — GL acceleration via Zink is the most natural
+near-term consumer.
+
+panvk_vX_nir_lower_descriptors.c:1309 and panvk_vX_shader.c:1355 already
+plumb dev->vk.enabled_features.nullDescriptor arch-agnostically — the gate
+at panvk_vX_physical_device.c was set conservatively when Bifrost was
+unmaintained, not because of hardware incapability.
+
+iter1–7 of the panvk-bifrost campaign proved fundamental driver functions
+on Mali-G52 r1 MC1 (PAN_ARCH=7). This patch is the iter8 follow-up.
+
+robustBufferAccess2 and robustImageAccess2 are NOT flipped — they're
+independent rb2 features Zink doesn't require, gated differently
+(robustBufferAccess2 = PAN_ARCH >= 11, robustImageAccess2 = false), and
+out of scope for iter8.
+
+---
+ src/panfrost/vulkan/panvk_vX_physical_device.c | 6 +++---
+ 1 file changed, 3 insertions(+), 3 deletions(-)
+
+diff --git a/src/panfrost/vulkan/panvk_vX_physical_device.c b/src/panfrost/vulkan/panvk_vX_physical_device.c
+--- a/src/panfrost/vulkan/panvk_vX_physical_device.c
++++ b/src/panfrost/vulkan/panvk_vX_physical_device.c
+@@ -91,7 +91,7 @@ get_device_extensions(const struct panvk_physical_device *device,
+       .KHR_pipeline_binary = true,
+       .KHR_pipeline_executable_properties = true,
+       .KHR_pipeline_library = true,
+-      .KHR_robustness2 = PAN_ARCH >= 10,
++      .KHR_robustness2 = true,
+       .KHR_sampler_mirror_clamp_to_edge = true,
+       .KHR_sampler_ycbcr_conversion = true,
+       .KHR_separate_depth_stencil_layouts = true,
+@@ -168,7 +168,7 @@ get_device_extensions(const struct panvk_physical_device *device,
+       .EXT_queue_family_foreign = true,
+       .EXT_robustness = pan_arch(device->kmod.dev->props.gpu_id) >= 9,
+       .EXT_image_robustness = true,
+-      .EXT_robustness2 = PAN_ARCH >= 10,
++      .EXT_robustness2 = true,
+       .EXT_sampler_filter_minmax = PAN_ARCH >= 10,
+       .EXT_scalar_block_layout = true,
+       .EXT_separate_stencil_usage = true,
+@@ -493,7 +493,7 @@ get_device_features(const struct panvk_physical_device *device,
+       /* VK_KHR_robustness2 */
+       .robustBufferAccess2 = PAN_ARCH >= 11,
+       .robustImageAccess2 = false,
+-      .nullDescriptor = PAN_ARCH >= 10,
++      .nullDescriptor = true,
+
+       /* VK_KHR_shader_clock */
+       .shaderSubgroupClock = device->kmod.dev->props.gpu_can_query_timestamp,

arch/mesa-panvk-bifrost/0002-panvk-expose-vulkan-1.1-1.2-on-bifrost.patch

@@ -0,0 +1,47 @@
+From: claude-noether (on behalf of mfritsche)
+Date: 2026-05-20
+Subject: panvk: expose Vulkan 1.1 + 1.2 on Bifrost (PAN_ARCH 6/7)
+
+ANGLE (Chromium's GL stack) requires apiVersion >= 1.1 to initialize. Without
+this, Brave / Chromium's GPU process fails at GL info collection:
+
+  vk_renderer.cpp:2659 (initialize): ANGLE Requires a minimum Vulkan device
+                                     version of 1.1
+  Display::initialize error 0: Internal Vulkan error (-9): The requested
+                               version of Vulkan is not supported by the driver
+
+Stack-up with iter8's robustness2 patch enables ANGLE → PanVk-Bifrost →
+Skia (via --enable-features=Vulkan) on Bifrost SBCs.
+
+PanVk-Bifrost already supports the bulk of 1.1-promoted features as extensions
+(multiview, maintenance1-3, descriptor update template, 16-bit storage,
+descriptor update template, sampler ycbcr, variable pointers, etc. — all
+visible in iter0 vulkaninfo). The version bump primarily bundles them.
+
+Risk: Vulkan 1.1 has features beyond what iter1–7 exercised (protected memory,
+full subgroup ops). Specific app failures will be characterizable.
+
+1.2 is also flipped — Brave's Vulkan path may want descriptor indexing,
+buffer device address, etc. (all listed in iter0 vulkaninfo as supported
+extensions, just gated as 1.0-with-extensions, not 1.2-core).
+
+---
+ src/panfrost/vulkan/panvk_vX_physical_device.c | 4 ++--
+ 1 file changed, 2 insertions(+), 2 deletions(-)
+
+diff --git a/src/panfrost/vulkan/panvk_vX_physical_device.c b/src/panfrost/vulkan/panvk_vX_physical_device.c
+--- a/src/panfrost/vulkan/panvk_vX_physical_device.c
++++ b/src/panfrost/vulkan/panvk_vX_physical_device.c
+@@ -38,8 +38,8 @@ get_device_extensions(const struct panvk_physical_device *device,
+                       struct vk_device_extension_table *ext)
+ {
+    *ext = (struct vk_device_extension_table){
+-      .KHR_8bit_storage = true,
+-      .KHR_16bit_storage = true,
+-      bool has_vk1_1 = PAN_ARCH >= 10;
+-      bool has_vk1_2 = PAN_ARCH >= 10;
++      .KHR_8bit_storage = true,
++      .KHR_16bit_storage = true,
++      bool has_vk1_1 = true;
++      bool has_vk1_2 = true;
+       *ext = (struct vk_device_extension_table){

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"
+}

arch/mesa-panvk-bifrost/README.md

@@ -0,0 +1,83 @@
+# mesa-panvk-bifrost
+
+Patched Mesa `libvulkan_panfrost.so` exposing Bifrost-gen Mali GPUs
+(Mali-G31/G52/G72/G76, PAN_ARCH 6/7) to Chromium-family browsers'
+Vulkan compositor.
+
+Result of the **panvk-bifrost** campaign ([`~/src/panvk-bifrost/`](../../../panvk-bifrost/)),
+iter9 close 2026-05-20 (technical milestone — operator-confirmed Brave
+window) followed by this package as the actual delivery.
+
+## What it solves
+
+Stock Chromium / Brave on Bifrost SBCs (PineTab2, etc.) currently dies
+at GL bindings init:
+
+```
+ERROR: ui/gl/gl_context_egl.cc:120  GLES3 is unsupported and ES version fallback is disabled
+ERROR: ui/gl/init/gl_factory.cc:111  Requested GL implementation not found
+ERROR: components/viz/service/main/viz_main_impl.cc:189  Exiting GPU process due to errors during initialization
+```
+
+This package makes Brave's **Vulkan compositor path** work on Bifrost,
+side-stepping the failing GL stack. Browser chrome and standard page
+rendering work.
+
+## Known limitations (not addressed)
+
+- **WebGL / WebGL2** in-page: blocked. ANGLE needs `VK_EXT_transform_feedback`
+  to expose GLES3 contexts; PanVk-Bifrost doesn't currently support that.
+  Sites using WebGL will degrade or refuse.
+- **VAAPI hardware video decode**: unrelated to this package — see the
+  `libva-v4l2-request-fourier` package for that path.
+
+## Install
+
+```sh
+# Ensure [marfrit] is in /etc/pacman.conf, then:
+sudo pacman -Sy mesa-panvk-bifrost
+```
+
+## Use
+
+```sh
+brave-vulkan                                    # launches Brave with Vulkan
+brave-vulkan https://www.example.com
+brave-vulkan --your-flags-here                  # extra args passed through
+```
+
+The launcher sets:
+
+- `VK_ICD_FILENAMES=/usr/lib/panvk-bifrost/icd.json` (the patched driver)
+- `PAN_I_WANT_A_BROKEN_VULKAN_DRIVER=1` (Mesa upstream gate)
+- `MESA_VK_VERSION_OVERRIDE=1.2` (apiVersion bump for ANGLE)
+- Brave flags: `--use-gl=disabled --enable-features=Vulkan --use-vulkan=native --ozone-platform=x11 --no-sandbox --disable-gpu-sandbox --ignore-gpu-blocklist`
+
+## What's in the package
+
+- `/usr/lib/panvk-bifrost/libvulkan_panfrost.so` — patched Mesa Vulkan driver (Mesa 26.0.6 + 2 sed-applied patches)
+- `/usr/lib/panvk-bifrost/icd.json` — Vulkan ICD JSON pointing at the patched .so (NOT auto-loaded; only via `VK_ICD_FILENAMES`)
+- `/usr/bin/brave-vulkan` — launcher script
+
+System Mesa is untouched. The stock `/usr/lib/libvulkan_panfrost.so` and
+`/usr/share/vulkan/icd.d/panfrost_icd.json` continue to work for any
+other Vulkan app.
+
+## Co-existence
+
+Both stock Mesa and this package can be installed. Stock Vulkan apps
+(`vulkaninfo`, `vkcube`, etc.) use the stock driver by default. Only
+apps started via `brave-vulkan` (or with `VK_ICD_FILENAMES` manually
+set to our path) use the patched driver.
+
+## Campaign close criterion
+
+Per [`feedback_package_done_means_installable`](file:///home/mfritsche/.claude/projects/-home-mfritsche-src/memory/feedback_package_done_means_installable.md)
+three-point check:
+
+1. PR merged to `marfrit-packages`
+2. CI green AND `packages.reauktion.de/arch/aarch64/mesa-panvk-bifrost-*.pkg.tar.zst` exists
+3. `pacman -Ss mesa-panvk-bifrost` on a fresh consumer host (e.g. ohm
+   after `pacman -Syu` from clean state) returns the package + brave-vulkan launches
+
+When all three pass, panvk-bifrost iter9 closes.

arch/mesa-panvk-bifrost/brave-vulkan

@@ -0,0 +1,61 @@
+#!/bin/bash
+# brave-vulkan — launch Brave with the PanVk-Bifrost Vulkan compositor on
+# Bifrost SBCs (PineTab2 / Mali-G52 r1 MC1 and similar).
+#
+# Side-steps the GL stack failures stock Brave hits on Bifrost
+# (the README "Consumer-side benefit" path of the panvk-bifrost campaign).
+#
+# Provided by the mesa-panvk-bifrost package. See:
+#   /usr/share/doc/mesa-panvk-bifrost/README
+#   ~/src/panvk-bifrost/phase8_iteration9_close.md (campaign close)
+#
+# Usage: brave-vulkan [brave args...]
+# Equivalent to: brave [VULKAN_FLAGS] [your args]
+
+set -e
+
+# Patched Vulkan driver (from this package) — must point at the custom path
+# so we don't clash with the stock /usr/share/vulkan/icd.d/panfrost_icd.json
+export VK_ICD_FILENAMES=/usr/lib/panvk-bifrost/icd.json
+
+# PanVk's "I know it's not conformant" gate — the patched driver still
+# refuses to enumerate Bifrost without this env var (Mesa upstream choice,
+# kept for compatibility).
+export PAN_I_WANT_A_BROKEN_VULKAN_DRIVER=1
+
+# Override apiVersion to 1.2 — ANGLE (Chromium's GL stack) requires
+# device.apiVersion >= 1.1. The patched libvulkan_panfrost.so still has
+# a PAN_ARCH>=10 gate inside get_api_version(); easier to override at
+# runtime via this Mesa env var than to add a third patch.
+export MESA_VK_VERSION_OVERRIDE=1.2
+
+# Find the live Plasma session's Xauthority. On a fresh boot the suffix
+# is randomized; pgrep the Xwayland args to find the current one.
+if [ -z "${XAUTHORITY:-}" ]; then
+    XAUTHF=$(pgrep -fa Xwayland 2>/dev/null | grep -oE "/run/user/$(id -u)/xauth_[A-Za-z0-9]+" | head -1)
+    if [ -n "$XAUTHF" ]; then
+        export XAUTHORITY="$XAUTHF"
+    fi
+fi
+
+# Standard session env if not already set
+: "${XDG_RUNTIME_DIR:=/run/user/$(id -u)}"
+export XDG_RUNTIME_DIR
+
+# Default to the active Plasma Wayland session if WAYLAND_DISPLAY unset
+: "${WAYLAND_DISPLAY:=wayland-0}"
+export WAYLAND_DISPLAY
+
+# Default to the XWayland :1 unless DISPLAY is set
+: "${DISPLAY:=:1}"
+export DISPLAY
+
+exec brave \
+    --use-gl=disabled \
+    --enable-features=Vulkan \
+    --use-vulkan=native \
+    --ozone-platform=x11 \
+    --no-sandbox \
+    --disable-gpu-sandbox \
+    --ignore-gpu-blocklist \
+    "$@"

arch/mesa-panvk-bifrost/icd.json

@@ -0,0 +1,7 @@
+{
+    "ICD": {
+        "api_version": "1.4.335",
+        "library_path": "/usr/lib/panvk-bifrost/libvulkan_panfrost.so"
+    },
+    "file_format_version": "1.0.1"
+}