marfrit
a4e7d8ab90
panvk-bifrost campaigns (r1..r4 Vulkan compositor + r5.video1 Vulkan
video decode) shipped before this repo existed; the deliverable
patches live in marfrit-packages, but the reasoning chain, phase docs,
and source-state evidence lived only in local working trees on the
development host.
This retrofit imports:
- mesa-panvk-bifrost/ — r1..r4 era phase docs (iter1..iter18)
(libmali stub blobs at iter18/blob/ excluded
— 109MB of RE artifacts replaced with a README
pointer)
- mesa-panvk-bifrost-video/ — sibling campaign phase docs + probe
- evidence/ — frozen .tgz source snapshots at each milestone
(basis for the 0005 patch diff generation)
Future iterations should branch off here from day one, so each iter is
a commit rather than a snapshot. See [[feedback-session-local-process-pins]]
for the process drift this retrofit closes.
Total: 1.9 MB across 124 files.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
109 lines
4.8 KiB
Plaintext
109 lines
4.8 KiB
Plaintext
iter9 Brave-on-PanVk-Bifrost breakthrough — captured 2026-05-20 on ohm
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(PineTab2 v2.0, RK3566, Mali-G52 r1 MC1, Mesa 26.0.6 + iter8 patch + iter9 patch + env override)
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===== CAMPAIGN PIVOT CONTEXT =====
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Goal pivoted from "TuxRacer via Zink-on-PanVk" to "Brave/Chromium GPU
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process boots via Vulkan on PanVk-Bifrost". Pivot driven by extremetuxracer
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not being in Arch repos + Chromium-Vulkan being the structurally bigger
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ecosystem win (per README's "Consumer-side benefit" section).
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===== THE WINNING COMBO =====
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Patched binary (iter8 + iter9 patches stacked):
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/home/mfritsche/panvk-patched-libs/libvulkan_panfrost.so (16.8 MB)
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/home/mfritsche/panvk-patched-libs/panfrost_icd_patched.json
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iter8 patch: KHR/EXT_robustness2 + nullDescriptor = true for PAN_ARCH 6/7
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iter9 patch: has_vk1_1 + has_vk1_2 = true for PAN_ARCH 6/7
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Runtime env:
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XDG_RUNTIME_DIR=/run/user/1001
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WAYLAND_DISPLAY=wayland-0
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DISPLAY=:1
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XAUTHORITY=/run/user/1001/xauth_<random> (find from `pgrep -fa Xwayland`)
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VK_ICD_FILENAMES=/home/mfritsche/panvk-patched-libs/panfrost_icd_patched.json
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PAN_I_WANT_A_BROKEN_VULKAN_DRIVER=1
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MESA_VK_VERSION_OVERRIDE=1.2 (bypasses get_api_version's
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PAN_ARCH>=10 gate at runtime;
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cleaner than another patch)
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Brave flags (the winners):
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--use-gl=disabled (CRUCIAL — skips GLES3 info collection;
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without this Chromium dies at ANGLE-
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Vulkan-on-Bifrost not exposing GLES3
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because PanVk-Bifrost lacks VK_EXT_
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transform_feedback)
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--enable-features=Vulkan (compositor uses Vulkan)
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--use-vulkan=native (use native Vulkan, no SwiftShader)
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--ozone-platform=x11 (Wayland ozone is incompatible with
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Vulkan per Chromium error msg; use
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X11 ozone via XWayland)
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--no-sandbox --disable-gpu-sandbox (so GPU process can access /dev/dri
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and VK_ICD_FILENAMES)
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--ignore-gpu-blocklist (force-enable Vulkan on Mali — Brave's
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internal blocklist may flag PanVk)
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===== EVIDENCE OF SUCCESS =====
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1. PanVk warning fires ONCE per GPU process startup (previously: 10x = 5
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crash-retries). GPU process is staying alive.
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2. No "Exiting GPU process due to errors during initialization" message.
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3. No "GLES3 is unsupported" / "eglCreateContext ES 3.0 failed" / "ANGLE
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Requires a minimum Vulkan device version of 1.1" errors.
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4. Brave ran for the full 25-second timeout. Process exited cleanly on
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timeout (histograms emitted during shutdown).
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5. Load page: https://www.example.com
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(Network fetch confirmed in logs.)
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6. dmesg --since "1 minute ago": NO panfrost/mali/gpu faults.
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7. Single benign warning:
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sandbox/policy/linux/sandbox_linux.cc:405: InitializeSandbox() called
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with multiple threads in process gpu-process.
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(Standard Linux GPU sandbox warning; non-fatal.)
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===== ITER-BY-ITER FAILURE CHAIN (now resolved) =====
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Run 1: stock libvulkan_panfrost.so + no env override
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→ Zink fell back to llvmpipe (iter8 RED finding).
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Run 2: iter8-patched lib (robustness2 + nullDescriptor exposed)
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→ Zink loaded ✓, glxgears 250 FPS ✓ (iter8 GREEN partial).
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→ But Brave's GPU process still failed at "GLES3 unsupported".
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Run 3: iter8-patched lib + --use-gl=disabled + --enable-features=Vulkan
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→ "'--ozone-platform=wayland' is not compatible with Vulkan"
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Run 4: + --ozone-platform=x11
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→ "GLES3 is unsupported and ES version fallback is disabled" (ANGLE)
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Run 5: + --use-gl=angle --use-angle=vulkan
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→ "ANGLE Requires a minimum Vulkan device version of 1.1"
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→ PanVk-Bifrost reports apiVersion=1.0.335
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Run 6: + iter9 patch (has_vk1_1/has_vk1_2 = true) — apiVersion still 1.0
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→ has_vk1_1 only controls extensions, NOT api version
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Run 7: + MESA_VK_VERSION_OVERRIDE=1.2 — apiVersion=1.2.335 ✓
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→ ANGLE Vulkan init succeeded ✓
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→ But ANGLE still couldn't create GLES 3.0 context (EGL_BAD_ATTRIBUTE)
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likely because PanVk-Bifrost lacks VK_EXT_transform_feedback
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Run 8: + --use-gl=disabled (bypass ANGLE GL entirely)
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→ 🎯 GPU process boots, Brave runs, page loads, no faults.
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===== WHAT'S STILL UNKNOWN =====
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- Visual confirmation: did the Brave window actually render correctly on
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the PineTab2 screen? (Pending operator confirmation.)
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- chrome://gpu state — what does Brave think of GPU capabilities now?
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- Sustained workload: did pages with rich graphics work, or just simple
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text pages?
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- WebGL / WebGL2: blocked by ANGLE-GLES3 gap (no transform_feedback).
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Probably broken; can be tested separately.
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- Did Skia Graphite engage, or just classic Vulkan compositor?
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