eh577-probe-test

name	eh577-probe-test
description	Use when probing, replaying packets against, polling interrupts from, or collecting dumps/logs for the EgisTec EH577 fingerprint sensor. Covers the local usbfs probe workflow, expected EH575-compatible behavior, finger-interaction testing, and how to record results safely.

EH577 Probe And Test

Start here when the task involves live device interaction or interpreting probe results.

Read first

Read only the files you need:

• AGENTS.md for the current device facts and workflow
• docs/research-log.md for chronology
• logs/2026-06-03-eh577-postinit18-analysis.txt for the strongest current result
• tools/eh577_usbfs_probe.c if you need probe behavior or packet mode details

Working model

Assume EH577 is an EH575-family device unless new evidence contradicts that.

Validated facts so far:

• bulk OUT is 0x01
• bulk IN is 0x82
• interrupt IN endpoints are 0x83 and 0x84
• EH575 post-init replay succeeds
• 64 14 ec returns a 5356-byte payload
• idle captures have produced an all-zero 5356-byte payload

Do not hardcode state bytes as fixed constants without repeated captures. Some SIGE replies vary across runs.

Preferred workflow

1. Reset the device before a fresh capture series.
2. Use eh575-auto or eh575-postinit 18 to establish the baseline.
3. If collecting raw payloads, set EH577_DUMP_DIR to a new dated directory under dumps/.
4. If checking finger events, prefer tools/eh577_guided_capture.sh so sudo is acquired up front and the touch/remove timing is scripted.
5. Compare idle vs touch vs repeated-run behavior before changing driver logic.

Commands

Device access here normally requires root.

For longer finger-interaction runs, prefer the guided helper because it now acquires sudo credentials up front before any delays and keeps them alive during the run if the capture command starts with sudo.

Reset:

sudo ./build/eh577_usbfs_probe /dev/bus/usb/003/004 reset

Auto-init:

sudo ./build/eh577_usbfs_probe /dev/bus/usb/003/004 eh575-auto

Post-init replay:

sudo ./build/eh577_usbfs_probe /dev/bus/usb/003/004 eh575-postinit 18

Interrupt polling during finger interaction:

sudo ./build/eh577_usbfs_probe /dev/bus/usb/003/004 poll-int 40

Replay with raw dumps:

mkdir -p dumps/2026-06-03-sample-run
sudo env EH577_DUMP_DIR="$PWD/dumps/2026-06-03-sample-run" \
  ./build/eh577_usbfs_probe /dev/bus/usb/003/004 eh575-postinit 18

Guided interrupt polling with scripted touch/remove timing:

./tools/eh577_guided_capture.sh \
  --delay-before-start 3 \
  --delay-before-touch 2 \
  --hold 4 \
  --delay-after-remove 2 \
  --cycles 2 \
  -- sudo -n ./build/eh577_usbfs_probe /dev/bus/usb/003/004 poll-int 40

Guided post-init finger-hold capture with dumps:

mkdir -p dumps/2026-06-03-sample-fingerhold
./tools/eh577_guided_capture.sh \
  --delay-before-start 3 \
  --delay-before-touch 1 \
  --hold 10 \
  --delay-after-remove 2 \
  --cycles 1 \
  -- sudo -n bash -lc 'export EH577_DUMP_DIR="$PWD/dumps/2026-06-03-sample-fingerhold"; ./build/eh577_usbfs_probe /dev/bus/usb/003/004 eh575-postinit 18'

What to record

For every meaningful run, capture:

• exact command used
• whether the device was freshly reset
• whether a finger was present, absent, touching, or swiping
• which packet responses changed
• whether 64 14 ec stayed zero-filled or gained entropy
• whether either interrupt endpoint returned data

Write a summary log under logs/ and keep raw dumps under dumps/.

Cautions

• plain ad-hoc sudo may expire during longer runs; prefer eh577_guided_capture.sh for finger-interaction captures so sudo is acquired before the timing starts
• dump files created as root may be owned by root:root
• interrupt silence in short tests does not prove interrupts are irrelevant
• an all-zero 5356-byte payload can still be a valid idle frame

Done criteria

The probe/test task is not complete until the result includes:

• the commands that were run
• what changed relative to prior captures
• whether the result supports or weakens the EH575-compatibility model