 marfrit
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9415b7e0f7
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Phase 8.1: kernel V4L2 device skeleton (out-of-tree module)
Out-of-tree Linux kernel module registering /dev/videoNN. Phase
8.1 scope: skeleton only — VIDIOC_QUERYCAP works, no codec
ioctls / no vb2_queue / no controls yet.
Real V4L2 plumbing throughout per "correctness before speed":
platform_device + v4l2_device + video_device, properly nested
with error paths and devm_kzalloc-managed lifetime. Per-cycle 9
discipline ports to kernel code: SPDX header, kernel coding
style (8-tab, static-by-default), kerneldoc on structs, no
shortcuts.
Files (~250 LOC total):
- kernel/Makefile — out-of-tree kbuild with checkpatch target
- kernel/daedalus_v4l2_main.c — module init/exit + probe/remove
Verification on hertz (Pi 5, 6.12.75+rpt-rpi-2712):
- Builds clean with -Wall -Wextra. No warnings.
- modprobe / rmmod round-trip clean. No dmesg taints beyond
the expected "out-of-tree taint" line.
- v4l2-ctl --list-devices shows: "daedalus-fourier V3D7+NEON
(platform:daedalus_v4l2): /dev/video0"
- VIDIOC_QUERYCAP returns driver/card/bus/caps as specified.
- v4l2-compliance: 44/48 passing. The 4 failures are exactly
the format/buffer ioctls Phase 8.2 will implement
(ENUM_FMT, G_FMT, Scaling, REQBUFS) — not skeleton bugs,
legitimately-absent features.
Documentation: docs/phase_8_1_closure.md captures full
verification output + Phase 8.2 plan.
Phase 8.1 acceptance criteria met:
- ✓ /dev/videoNN appears via v4l2-ctl --list-devices
- ✓ VIDIOC_QUERYCAP responds with sensible values
- ✓ rmmod is clean (no kref leaks)
- ✓ v4l2-compliance passes except for explicit Phase 8.2 work
Next: Phase 8.2 chardev bridge for kernel ↔ daemon IPC.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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2026-05-18 15:03:22 +00:00 |
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marfrit
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c7d8050cc9
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Initial scaffold: daedalus-v4l2 sibling repo
V4L2 stateless decoder for Pi 5, backed by sibling
daedalus-fourier kernel library (VP9 + AV1 CDEF + H.264 video
decode kernels on VideoCore VII compute + ARM NEON).
Architecture locked 2026-05-18 by mfritsche per
daedalus-fourier/docs/phase8_scoping.md:
- Option B: Linux kernel V4L2 shim + userspace daemon (not
v4l2loopback). Real /dev/videoNN; proper DRM PRIME for
browser zero-copy.
- Option γ: dlopen FFmpeg at runtime as parser. No vendoring;
fastest to v1.
- Sibling repo (this repo): V4L2-side work outside of
daedalus-fourier so kernel-library API stays clean.
Components:
kernel/ - Linux out-of-tree kernel module (GPLv2; V4L2
device + chardev bridge to userspace daemon)
daemon/ - userspace decoder daemon (BSD-2-Clause; links
libdaedalus_core.a from sibling; dlopens FFmpeg)
docs/ - architecture + 7-phase roadmap (8.1..8.7)
include/ - shared headers between kernel and daemon
Roadmap (7 sub-phases, ~1 week each):
8.1 kernel skeleton (/dev/videoNN with no-op ioctls)
8.2 chardev bridge (kernel ↔ daemon ping-pong)
8.3 daemon FFmpeg dlopen + parse path
8.4 VP9 end-to-end via daedalus_dispatch_*
8.5 dmabuf / DRM PRIME for zero-copy
8.6 AV1 + H.264 codec support
8.7 performance: hit 30fps@1080p (project floor)
No code yet — only README + design docs + directory structure.
First implementation work starts in Phase 8.1 next session.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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2026-05-18 14:54:56 +00:00 |
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