Open ampere-vp9-enablement to enable VP9 hardware decode on RK3588 ampere
(rkvdec / vdpu381 register layout). Sibling to ampere-kernel-decoders
(closed at HEVC bit-perfect 2026-05-17 ~00:42).
Phase 0 substrate locked: upstream status (Collabora roadmap, no series
posted), legacy code reference (rkvdec-vp9.c 1042 lines, vdpu341),
vdpu381 pattern reference (rkvdec-vdpu381-hevc.c, struct-based regs +
common-file split), work-plan outline, open questions (chiefly: where
is the vdpu381 VP9 register layout documented), risk register.
Phase 1 (architectural plan + Sonnet review) next session.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
