Y2LINUX-M3-AUDIO-01 — owner deployment

This is an unqualified audio candidate, not an M3 completion claim. The qualified DEV-02 core configuration and RAM reservations are retained. USB reconnect remains deferred as #27; do not cycle the development cable in this pass. No assistant flashing or live codec/PMIC register writes are authorized.

Artifact directory: /home/luca/Dokumente/Code/Y2Linux/out/y2linux-m3-audio-01/. Exact sizes/hashes are in SHA256SUMS and result.json; verify before deployment:

cd /home/luca/Dokumente/Code/Y2Linux/out/y2linux-m3-audio-01
sha256sum -c SHA256SUMS

Update the removable SD content

Yes, the SD rootfs needs updating for ALSA utilities, fixtures, runtime fixes and the matching DRM module. Keep the existing Y2ROOT partition/filesystem and its persistent SSH host keys. rootfs.tar is the update source; rootfs.ext4 is an independently validated fresh filesystem image, not an internal eMMC image. Do not write a whole filesystem image onto the currently mounted/live root.

Owner: shut down the Y2, remove its microSD and attach it to a Linux SD reader. Identify the actual removable card and its existing Y2ROOT partition with:

lsblk -o NAME,PATH,TRAN,RM,SIZE,FSTYPE,LABEL,UUID,MOUNTPOINTS

Select only the physical SD reader/card whose ext4 partition has LABEL=Y2ROOT and UUID 79324c69-6e75-4801-8000-000000000001. Do not guess a /dev/sdX target; do not use the PC system disk or any Y2 internal partition. Substitute that identified partition path below; these commands preserve files absent from the new tar, including old module trees and retained hardware logs:

Y2_SD_PARTITION=/dev/REPLACE_WITH_IDENTIFIED_SD_PARTITION
sudo mkdir -p /mnt/y2root
sudo mount "$Y2_SD_PARTITION" /mnt/y2root
findmnt /mnt/y2root
sudo tar -C /mnt/y2root --numeric-owner --overwrite \
  --exclude='./etc/dropbear' --exclude='./etc/dropbear/*' \
  --exclude='./root/.ssh' --exclude='./root/.ssh/*' \
  -xpf /home/luca/Dokumente/Code/Y2Linux/out/y2linux-m3-audio-01/rootfs.tar
sudo cat /mnt/y2root/etc/y2linux/build-id
sudo test -s /mnt/y2root/root/.ssh/authorized_keys
sudo test -x /mnt/y2root/usr/bin/aplay
sync
sudo umount /mnt/y2root

Expected build-id is Y2LINUX-M3-AUDIO-01. This updates files without formatting or repartitioning. Keep the SD installed for the next boot.

BOOTIMG-only SP Flash Tool procedure

1. Use the existing known-working Y2 scatter/download-agent workflow. Select

   Download Only. Deselect every partition, then select BOOTIMG only.

2. Set BOOTIMG's file to this candidate's BOOTIMG.img. Inspect that PRELOADER,

   LK, partition table, NVRAM/calibration and all other partitions are unchecked. Never select Format All or Firmware Upgrade.

3. With the Y2 powered off, click Download and perform the established connection

   sequence. Wait for successful completion. The owner performs this operation.

4. Disconnect USB, boot with the updated SD, wait approximately ten seconds, then

   attach USB once to the development PC. Expected kernel is 6.18.0-y2linux-m3audio01. USB serial/observer tags retain DEV-01 compatibility.

First SSH inspection — no playback yet

On the PC:

ssh -i /home/luca/.ssh/y2linux_ed25519 [email protected]

On the Y2:

uname -a
cat /etc/y2linux/build-id
cat /proc/asound/cards
cat /proc/asound/pcm
cat /proc/asound/devices
aplay -l
aplay -L
amixer -c Y2Audio
cat /sys/kernel/debug/regulator/regulator_summary
cat /sys/kernel/debug/clk/clk_summary
dmesg

Expected ALSA card ID/name: Y2Audio. PCM device 0 is Y2 Headphone Playback; use hw:CARD=Y2Audio,DEV=0. Initial CPU/PCM capabilities are **stereo S16_LE, 44100 and 48000 Hz**, not yet physically qualified. No capture or speaker PCM. AFE's internal back end is Y2 Second I2S, CPU DAI I2S, upstream codec DAI cs43130-asp-pcm. VGP2 must report 1800 mV, with the GPIO supply dependency chain present. The speaker GPIO8 hog must stay low.

If the card is missing, a supply enable failed, or dmesg reports a DAC reset, clock-ready timeout or I2C errors, collect evidence and stop before playback. Do not use i2cset/devmem, whole regmap dumps, or a high-gain speaker test.

First controlled headphone test

Owner: insert headphones; keep them off your ears for the first short run. Headphone pin is disabled at card registration. Upstream PCM reset gain is -60 dB; no mixer state is automatically restored. Set a known conservative level, stereo routing, then enable the headphone endpoint:

amixer -c Y2Audio cset name='PCM Ch Select' 0
amixer -c Y2Audio sset Master 207,207
amixer -c Y2Audio sget Master
amixer -c Y2Audio sset Headphone on

Raw Master value 207/255 = -24 dB (0.5 dB steps). Confirm both channels show -24 dB. The fixture adds -30 dBFS peak, lasts three seconds and has 50 ms fades; left is 440 Hz and right 660 Hz. No sustained or full-scale tone.

In one SSH terminal, capture bounded live state during the test:

for n in 1 2 3 4 5; do
  cat /proc/uptime
  cat /sys/bus/platform/devices/11220000.audio-controller/state
  cat /proc/asound/card0/pcm0p/sub0/status
  sleep 1
done

In the playback terminal, the exact first command is:

aplay -D hw:CARD=Y2Audio,DEV=0 --period-size=1024 --buffer-size=8192 /usr/share/y2linux/audio/headphone-44100.wav

After it finishes:

y2-audio-collect > /tmp/m3-after-first.txt
amixer -c Y2Audio sset Headphone off

Report whether physical headphone output is audible/clean and whether each side is correct. Do not raise gain automatically if silent. After a clean first run, repeat two short 44.1 kHz runs, interrupt one with Ctrl-C and restart, then test headphone-48000.wav with the same command and constraints. Disable Headphone between test groups. Stop on loud noise/pops, DAC reset, corruption or kernel errors. Speaker, EINT16 jack/ACCDET and high-resolution formats remain separate.

Evidence to correlate

Retain full y2-audio-collect output over SSH in repository hardware evidence before/during/after playback. Inspect ALSA hw_params/status and XRUNs, AFE IRQ counts in /proc/interrupts, cumulative period callbacks and current DMA pointer, CONN0, CON3, DMA bounds, codec probe/clock messages, regulator usage/1.8 V and CCF states. AFE state is a bounded read-only attribute that guards MMIO with runtime PM; do not dump its raw regmap when clock-gated. /sys/kernel/debug/asoc/ exposes DAPM/card state. Do not equate DMA progress to external pad activity or audible output. Actual LRCK/BCLK accuracy may require physical clock measurement.

Classify failures before changing a layer: A card probe; B PCM/DMA; C wrong I2S with advancing DMA; D codec brownout/reset; E analog route/mute; F userspace underruns; G rate/clock accuracy. No M3 closure until physical playback, safe stop/restart, repeated runs and supported-rate checks pass without kernel errors.