hil-regression

name	hil-regression
description	Diagnose a HIL CI failure on real WS63/BS2X silicon — compare the failed CI run against the last passing run, identify whether the regression is caused by a code change, toolchain update, or rig issue, and output a triage report. Use when a HIL CI job fails on the main branch or a PR.
disable-model-invocation	true

HIL Regression Diagnosis Skill

Diagnoses HIL CI failures on real silicon. Run when a hil.yml CI job fails on a commit that should be safe (e.g. a docs-only change fails HIL → rig issue; a DMA change fails HIL → likely code regression).

User-invoked (/hil-regression). It reads CI logs, does NOT flash hardware.

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Usage

# Diagnose the latest failed HIL CI run (autodetects run ID):
bash .agents/skills/hil-regression/regression.sh

# Diagnose a specific run:
bash .agents/skills/hil-regression/regression.sh --run 28502888903

# Show pass/fail history for the last 30 days:
bash .agents/skills/hil-regression/regression.sh --history

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Diagnosis methodology

Phase 1 — Gather data

# 1. Find the latest failed HIL CI run:
gh run list --workflow hil.yml --limit 5 --json databaseId,conclusion,headBranch,displayTitle

# 2. Fetch the failed job's logs:
gh run view <run-id> --log --job <job-name> > /tmp/hil-fail.log

# 3. Find the last passing run on the same branch:
gh run list --workflow hil.yml --branch main --limit 10 --json databaseId,conclusion
gh run view <passing-run-id> --log > /tmp/hil-pass.log

# 4. Check what code changed between the two runs:
git log --oneline <passing-sha>..<failing-sha>
git diff --stat <passing-sha>..<failing-sha>

Phase 2 — Classify failure

Symptom	Likely cause	Action
No UART output at all	Boot hang: wrong loaderboot, flash address, or power	Check ADDRESS and LOADERBOOT in the CI config. Compare with hil-smoke --preflight.
Garbled UART	Baud mismatch: clock-tree change affects UART divider	Check TIMER_CLOCK_HZ / UART clock source in the diff.
Specific test FAILED	Code regression in the exercised driver	git diff <passing-sha>..<failing-sha> -- crates/hisi-hal/src/<driver>.rs
All tests FAIL (incl. ones not touched)	Rig issue: board disconnected, probe-rs failed, power cycled	Check the CI runner logs for hardware errors, USB resets, timeout on probe-rs run.
Intermittent (passes locally)	Board contact / wiring / timing edge	Re-run HIL CI (gh run rerun <run-id>). If 2/3 passes → wiring flaky, not code.

Phase 3 — Produce report

# HIL Regression Report

## Commit
<failing-sha> by <author> on <date>
<commit-message>

## CI Run
<url-to-run>
<workflow> / <job> — <conclusion>

## Diff vs last passing
<files changed, summary>

## Diagnosis
**<RIG / CODE / TOOLCHAIN / INTERMITTENT>**

<detailed evidence>

## Next step
- If RIG: <what to check on the board / CI runner>
- If CODE: <which file/line is suspect, what  >
 If TOOLCHAIN: 
 If INTERMITTENT: