marfrit
902e855d92
iter12 hit a wall: Brave's ANGLE-Vulkan path requires GLES3, which requires VK_EXT_transform_feedback, which PanVk-Bifrost did not implement. This iter implements that extension, unlocking the full ANGLE-Vulkan-on-Bifrost stack. The implementation follows Panfrost-Gallium's well-validated XFB lowering (nir_io_add_intrinsic_xfb_info + pan_nir_lower_xfb) wired into the PanVk shader pipeline after nir_lower_io. Adds 4 XFB buffer address sysvals plus per-draw num_vertices to the graphics sysval struct. Buffer state is tracked on the cmd buffer; per-draw sysval upload populates either the bound buffer's GPU address or PAN_SHADER_OOB_ADDRESS (memory-sink) so XFB-capable pipelines used outside Begin/End survive without GPU fault — the Panfrost-Gallium idiom from gallium/drivers/panfrost/ pan_cmdstream.c:1350. Verified on PineTab2 (Mali-G52 r1 MC1, RK3566): - /tmp/panvk-iter13/probe_xfb: 3 vertices captured byte-exact - /tmp/panvk-iter13/probe_xfb_nodraw: XFB pipeline used without Bind/ Begin/End survives — DEVICE_LOST regression closed - Brave 148 with --use-angle=vulkan: WebGL 2.0 (OpenGL ES 3.0) creates cleanly, renderer reports "ANGLE (ARM, Vulkan 1.2.335 (Mali-G52 r1 MC1), panvk)" - chrome://gpu graphics feature status: Canvas/Compositing/OpenGL/ Rasterization/WebGL/WebGL2/WebGPU/Video Decode all hardware accelerated Phase docs: - ~/src/panvk-bifrost/phase4_iter13_close.md (build green) - ~/src/panvk-bifrost/phase5_iter13_close.md (review fixes applied) - ~/src/panvk-bifrost/phase6_iter13_close.md (Brave integration green) pkgver bumped 26.0.6.r2 -> 26.0.6.r3; iter13 patch applied via unified-diff (the 328-line change scope is past sed-of-individual- lines territory). Sanity checks in prepare() verify the patch landed. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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_feedbackto 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-fourierpackage 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 viaVK_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.zstexists pacman -Ss mesa-panvk-bifroston a fresh consumer host (e.g. ohm afterpacman -Syufrom clean state) returns the package + brave-vulkan launches
When all three pass, panvk-bifrost iter9 closes.