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marfrit 489d6e3862 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>

2026-05-20 11:03:59 +02:00

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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/), 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

# Ensure [marfrit] is in /etc/pacman.conf, then:
sudo pacman -Sy mesa-panvk-bifrost

Use

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 three-point check:

PR merged to marfrit-packages
CI green AND packages.reauktion.de/arch/aarch64/mesa-panvk-bifrost-*.pkg.tar.zst exists
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.

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