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>
74 lines
2.8 KiB
Plaintext
74 lines
2.8 KiB
Plaintext
iter5 vertex+UBO probe — captured 2026-05-19 on ohm
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(PineTab2 v2.0, RK3566, Mali-G52 r1 MC1, Mesa 26.0.6, kernel 7.0.0-danctnix1-6)
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Source: panvk-bifrost/iter5/{probe_vbo_ubo.c, .vert, .frag, Makefile}
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Deployed to: /tmp/panvk-iter5/
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===== RUN #1 (baseline) =====
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[step] vkCreateInstance
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WARNING: panvk is not a conformant Vulkan implementation, testing use only.
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[info] gpu='Mali-G52 r1 MC1'
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[step] vkCreateDevice
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[step] vkCreateBuffer vertex buffer
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[step] vkCreateBuffer UBO
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[step] vkCreateDescriptorSetLayout (UBO @ vertex)
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[step] vkCreatePipelineLayout + shaders
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[step] vkCreateGraphicsPipelines
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[step] record cmd buffer
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[step] submit + wait
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[step] verify
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[info] center (32,28) = 0xff5d564c (R=4c G=56 B=5d)
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[info] TL=0x00000000 TR=0x00000000
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[info] covered (non-clear) pixels = 338 / 4096
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[PASS]
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===== RUN #2 (VK_LAYER_KHRONOS_validation) =====
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[no validation warnings]
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covered = 338 [PASS]
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===== STABILITY: 5 reruns =====
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covered = 338 [PASS] x5
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7/7 PASS after coverage-range fix.
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===== INITIAL FAILURE NOTE =====
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First run reported "coverage out of range: 338 (want 800..1600)" — that was a
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verification-side arithmetic error on my (claude-noether's) part, not a driver
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issue. Triangle area = 0.5 * 0.8 * 0.8 = 0.32 sq units in NDC; viewport area
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is 4 sq units, so 8% coverage = ~328 pixels. The driver produced exactly 338,
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which matches the expected coverage within edge-rule tolerance.
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Substantive PASS criteria (interpolated center color, clear corners) were
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satisfied on the first run; only the loose coverage-range check needed
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calibration. Fixed in-tree at `iter5/probe_vbo_ubo.c`.
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===== KEY OBSERVATIONS =====
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1. Vertex input binding works:
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binding 0: stride 32, INPUT_RATE_VERTEX
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attribute 0: R32G32_SFLOAT, offset 0 (pos)
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attribute 1: R32G32B32_SFLOAT, offset 16 (color)
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GPU correctly fetched both attributes from the bound vertex buffer.
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2. UBO binding at vertex stage works:
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mat4 transform with scale 0.8 in x/y was correctly applied.
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Triangle vertices at NDC (-0.5,-0.5)/(0.5,-0.5)/(0,0.5) scaled to
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(-0.4,-0.4)/(0.4,-0.4)/(0,0.4) — visible from the 338-pixel coverage
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(matches 0.8-scaled area, NOT unscaled 0.5-scaled area which would be
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~500 pixels).
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3. Varying interpolation works:
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center pixel at (32, 28) has R=0x4c G=0x56 B=0x5d. All three vertex
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colors (red/green/blue) contributed via barycentric interpolation —
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none of the channels are zero, none are saturated, all are in a
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reasonable middle-of-range value.
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4. Bifrost vertex-side descriptor model handles UBO + vertex-stage shader
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correctly (the headline hypothesis for this iter — that vertex-stage
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descriptor binding would fail on Bifrost — did not materialize).
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5. Deterministic across runs: identical 338 covered pixels each time.
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No GPU faults, no validation warnings, all 7 runs identical.
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