Low Power Verification · All levels

Low-Power Signoff Criteria: Debug Playbook

Debug Playbook for Low-Power Signoff Criteria.

Debug playbook

Debug Playbook for Low-Power Signoff Criteria is anchored on illegal transition rate, corruption incidence, and deterministic replay quality under low-power scenarios. Convert observations into mechanism-backed and owner-bound actions.

Freeze seed, metadata, and boundary under investigation.
Locate first persistent low-power phase divergence.
Classify mechanism: setup, transition, boundary, retention, or X-prop class.
Apply one focused reproducer and one bounded fix.
Re-run determinism and broader regression matrix.

Review memo template

diagram

LPV REVIEW MEMO - LPV Debug & Signoff / Low-Power Signoff Criteria

1. Symptom
   - Failing metric: illegal transition rate, corruption incidence, and deterministic replay quality under low-power scenarios
   - Trigger context: <seed/mode/sequence>
   - First failing phase: <entry/off/exit/boundary>

2. Mechanism hypothesis
   - Candidate mechanism: Credible low-power signoff is evidence-driven and multi-dimensional: structural clean status, dynamic transition coverage quality, unresolved bug risk, and waiver governance must all close together. Criteria should define mandatory gates for each power domain and state transition, including isolation timing correctness, retention integrity across repeated cycles, reset-power-clock interaction safety, and no unsafe X escape into always-on control paths. Signoff reviews must also require production realism: representative software sequences, corner-case power cycling, and observability hooks for post-silicon diagnosis. Any residual waiver should include trigger conditions, mitigation validation, owner, and expiry, with explicit proof that field exposure is bounded. This prevents schedule-driven signoff from becoming a documentation exercise detached from real operational risk.
   - Competing hypotheses: setup, transition race, boundary bug, retention drift, X-prop noise
   - Missing evidence: <trace/assertion/report>

3. Proposed action
   - Smallest reversible change: <intent/RTL/checker/flow>
   - Expected movement: <failure trend/replay stability>
   - Regression risk: compatibility, coverage, signoff delay

4. Signoff
   - Required artifact: evidence packet for Low-Power Signoff Criteria: transition timeline, assertions, and before-after replay summary
   - Required owners: LPV lead, power-intent owner, LPV Debug & Signoff owner
   - Final decision: ship, bounded rollout, rollback, or escalate

Low-power verification deep dive

Signoff confidence comes from triage discipline, reproducible proof, and explicit residual-risk decisions.

Concept diagram

diagram

LPV SIGNOFF LADDER

reproduce -> classify -> isolate boundary -> bounded fix -> replay -> signoff decision

Metric graph

diagram

SIGNOFF CONFIDENCE

open ambiguous failures  ██████
reproducible closures    ███████
residual-risk unknowns   ███

Metrics and artifacts to collect

X-prop triage classification report
bug root-cause closure packet
regression stability and recurrence trend
signoff checklist completion matrix

Mini case study

A signoff block cleared after the team replaced broad waivers with boundary-specific evidence and replay criteria.

Debug branches

Classify X behavior before broad waiving.
Capture one definitive artifact packet per closure claim.
Define residual risk and rollback path at signoff.

Senior review question

Ask: what exact low-power transition boundary failed first, and which artifact proves the closure claim reproducibly?

Key takeaways

Tie each LPV claim to a concrete transition boundary and one proving artifact.
Prefer minimal reversible fixes with explicit owner and rollback criteria.

Common pitfalls

Treating power-aware failures as random before boundary classification.
Waiving X-prop failures before proving impact and root cause.
Declaring closure without deterministic replay across key modes.

Debug ladder

Sequence: reproduce -> classify -> isolate boundary -> prove mechanism -> bounded fix.

Avoid mixed fixes before first-principles classification.

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