Reborn Product Pass v2 — audit, decisions and ledger

Design: Product UI v2 · navigation · platform boundary · previews (v2, since replaced by the v3 previews).

1. Product simplification

2. UI pruning ledger

3. Unavailable cleanup

Before: 67 "unavailable / not available / not exposed" occurrences in UI and application sources, including generic value rendering of every missing platform field as Unavailable on normal pages. After: no user-visible normal-page string uses that pattern (enforced by normal_screens_never_show_engineering_terms_or_generic_unavailable and empty_library_states_name_the_problem_without_generic_unavailable). Internal error strings remain in the application but are mapped by friendly_error (Wi-Fi is starting. Try again in a moment.). Diagnostics states a missing field as Not reported, which is accurate there.

4. Boot

• Old: stock preloader/LK logo → kernel → initramfs splash with a

  photographic scene, taglines and a bouncing bar → a different Reborn boot screen (Reborn / MUSIC LIVES ON / Starting music services) → UI.

• New: preloader and LK unchanged → the initramfs splash shows the Reborn

  mark on #090B0D with a breathing gold rule → Reborn takes the display with the pixel-identical frame → 6-frame dissolve into the UI.

• Stage ownership: LK logo (stock, untouched) → reborn-splash from the

  initramfs after the unchanged charger and voltage gate (KD_GRAPHICS keeps fbcon hidden) → Reborn via the existing READY/RELEASED/PRESENTED handoff.

• Timing: no wait was added. The splash pulse costs one 40×2 px fill

  per 50 ms poll that already existed; the dissolve starts only after the first UI frame is ready and lasts ~200 ms. The Y2 was not run, so splash visibility, process start, first frame and ready times were not measured on hardware; Reborn's startup.phase events and the splash events.jsonl record them on the next boot.

• Flashes: the background is the same #090B0D in the splash, Reborn's

  first frame and the UI; fbcon stays in KD_GRAPHICS. The LK→kernel transition is owned by stock firmware and was not changed.

5. Shutdown

• Old: Reborn saved state and exited after its acknowledgement. Its DRM

  device closed with the backlight on, so the kernel's fbdev emulation restored its own buffer (stale, console or white) until power was cut.

• New: UI fades (7 frames) → Reborn mark (Battery empty on

  low-battery shutdown) while audio, session and database close → mark fades → black frame → backlight off (bl_power) → acknowledgement → exit. The DRM device stays open until the process exits. Visuals take ~0.9 s.

• Platform: the coordinator turns every backlight off after stopping or

  killing Reborn and before busybox poweroff/reboot, so a crashed or hung Reborn still ends dark. The platform deadline (10 s for user requests) and its continuation without an acknowledgement are unchanged.

7. Wheel

• Root cause (software, from source): InputManager::poll_at gave every

  record of a 15 ms read batch the same Instant::now() and accelerated from the second same-direction event within 180 ms (previous_steps + 1). Two real detents read in one batch, or one bounced data-ready edge re-reading the latched APT32F frame (the driver emits a press/release pair per IRQ), moved 1 + 2 rows; brisk rotation reached 3–6 rows per detent. The physical bounce rate was not captured on hardware.

• Path: APT32F I²C frame → apt32f-wheel KEY_UP/PAGEUP/DOWN/PAGEDOWN

  press+release → evdev → InputManager (cadence, dedupe) → NormalizedInput::Wheel* → ActionRouter (screen-off drop) → Action::Wheel* → Ui::wheel (context policy).

• Dedupe: kernel timestamps (EVIOCSCLOCKID → monotonic); same direction

  under 8 ms is one detent; releases and autorepeat are never detents.

• Acceleration: 1 step until four detents of one rotation; then 2 (≤110 ms

  smoothed interval), 3 (≤70 ms after 6), 4 (≤45 ms after 10). Reset after 220 ms, on reversal, device loss or a backwards clock.

• Contexts: long library lists use the suggestion; everything else one

  step; Now Playing volume ±2.

9. Information removed from normal screens

Kernel version, boot ID, kernel taint, Reborn/Y2Linux commits, build ID, rootfs version, platform build; CPU frequency/governor/idle states, load, memory, die temperatures, cooling; SOC source/confidence/calibration, supply voltage, current, pack temperature, low-battery policy; filesystem, UUID, controller clocks, transport errors; IP, route, DNS, signal dBm, RX/TX; SFTP/SSH, USB address, authentication, DMA counters; BlueZ/BlueALSA, PCM format/rate/channels, codec policy, trust, reconnect state; ALSA format, rate, hw_params, decoder/DSP formats; update scope, journal, signing key ID, sequence, rollback; capability implemented/enabled/qualified flags; reset plan commands; benchmark controls.

10. Feature UX summary

Music, Queue, Wi-Fi, Bluetooth, codec, USB, battery, storage, update and reset behave as described in Product UI v2. The codec preference row is hidden on the current platform policy (SBC only at runtime); it appears automatically when an enabled optional codec is usable with the connected peer.

11. Performance

• Rendering stays dirty-flag driven at ≤30 fps, visible rows only. The boot

  dissolve renders 6 extra frames once; the shutdown 27 frames once.

• Platform polling: one worker instead of two; a y2-platform process runs

  only while a platform-backed screen is visible (every 15 s, 4 s on PC Transfer) or after an explicit operation, never with the display off. The previous design refreshed every 10 s on platform pages via a second worker.

• Screen-off cadence is unchanged (50 ms loop); no new wake sources.

  Battery remains a 2 s file read of the platform power record.

16. Remaining product limitations

• Battery percentage is the platform's provisional voltage estimate; there

  is no measured current or calibrated capacity.

• Software updates need an owner-configured update channel; without one the

  device says updates are installed with a computer.

• PC Transfer is authenticated SFTP over USB; it is not a USB mass-storage

  drive, and loaded USB transfer failed the last physical CPU qualification.

• Optional Bluetooth codecs remain disabled by platform policy, so SBC is

  the only codec offered.

• No sleep/suspend: screen-off keeps the system running.
• Brightness and the shutdown backlight sequence are implemented against the

  standard backlight class and were not physically observed.