marfrit
0de0288dce
Brings daedalus_v4l2 from "standalone test client" to "VAAPI-
discoverable decoder" by adding the surface formats and
media-controller plumbing that libva-v4l2-request-fourier
(sibling repo) requires.
libva-v4l2-request-fourier patches (pushed separately):
- b5b3acf: daedalus_v4l2 added to known_decoder_drivers
- 2146341: meson option gate
This commit (daedalus-v4l2 side, 3 production changes):
1. V4L2_PIX_FMT_NV12 (single-plane) on CAPTURE
- Added to daedalus_capture_formats[] alongside NV12M + P010
- daedalus_fill_capture_fmt handles num_planes=1 case
(sizeimage = W*H*3/2, bytesperline = W)
- daemon pack_nv12_single_to_plane: Y at base+0,
interleaved CbCr at base+(stride*H); same byte content
as NV12M two-plane, different layout
- Required because libva-v4l2-request-fourier's video.c
only knows non-multi-plane NV12 (it advertises
v4l2_mplane=true but uses the single-plane fourcc).
- Verified byte-exact via test_m2m_stream against
ffmpeg -pix_fmt nv12 reference (VP9 1080p 10 frames,
31 MB).
2. V4L2 Request API media ops
- daedalus_media_ops = { vb2_request_validate,
v4l2_m2m_request_queue } assigned to mdev.ops before
media_device_init.
- Without this, MEDIA_IOC_REQUEST_ALLOC returned
-ENOTTY and no VAAPI consumer could allocate a
media_request.
3. Stateless control registration via v4l2_ctrl_new_custom
- Switched from v4l2_ctrl_new_std_compound(NULL p_def)
to v4l2_ctrl_new_custom — pattern rkvdec/cedrus/
hantro use. Adds a no-op s_ctrl callback.
Verification (hertz, Pi 5, 6.12.75+rpt-rpi-2712):
LibVA trace through `ffmpeg -hwaccel vaapi`:
vaInitialize / Profiles / Entrypoints / CreateConfig /
QuerySurfaceAttributes / CreateSurfaces / CreateContext
(cap_pool: 24 slots, 1 plane each) / CreateBuffer
(slice + picture params) / MEDIA_IOC_REQUEST_ALLOC
— all succeed.
Standalone NV12 decode path:
test_m2m_stream vp9_1080_stream.ivf out.nv12 1920 1080 vp9 nv12
→ 10/10 frames, byte-exact vs ffmpeg -pix_fmt nv12
vainfo (via libva-v4l2-request-fourier with our driver):
7 VAProfile entries with VAEntrypointVLD
(H264 Main/High/CBaseline/MultiviewHigh/StereoHigh,
VP9Profile0, AV1Profile0)
What's NOT here (Phase 8.12):
The libva trace stops at VIDIOC_S_EXT_CTRLS returning
EINVAL when populating V4L2_CID_STATELESS_VP9_FRAME on
the request. The compound-control payload validation
against the kernel's expected struct shape rejects.
This isn't a "missing line" fix — it needs proper
stateless control plumbing (the SPS/PPS/SliceParams
get_dims, validate, default-value paths that in-tree
rkvdec/cedrus/hantro implement to satisfy v4l2-core's
std_validate). Documented as Phase 8.12 scope.
The shipped integration is itself a meaningful deliverable:
all the framework scaffolding is in place; the remaining
gap is well-characterised and bounded.
See docs/phase_8_10_11_closure.md for the full trace
analysis + next-phase plan.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
kernel/ — daedalus-v4l2 Linux kernel module
Out-of-tree kernel module providing a V4L2 stateless decoder device that forwards work to a userspace daemon.
Status
Scaffold only. Phase 8.1 not yet started.
Build (when implemented)
make -C /lib/modules/$(uname -r)/build M=$(pwd)
sudo insmod daedalus_v4l2.ko
v4l2-ctl --list-devices # confirm /dev/videoNN appears
Layout (planned)
Makefile— kbuild stubdaedalus_v4l2_main.c— module init + V4L2 device registrationdaedalus_v4l2_chardev.c—/dev/daedalus-v4l2chardev for daemon communicationdaedalus_v4l2_v4l2.c— V4L2 ioctl dispatch (stateless controls)
License
GPLv2. Required for kernel module symbol compatibility.
Phase 8.1 starting point
Minimal example: register a /dev/videoNN that returns -ENOSYS on every ioctl. Validates that the kernel build works and v4l2-ctl can see the device.