Save/Restore Handshake Sequencing: Step-by-Step Walkthrough

Step-by-step analysis walkthrough

Use this sequence when owning Save/Restore Handshake Sequencing in a low-power verification review.

1. Freeze deterministic reproducer with mode and seed metadata.

2. Trace domain, supply, and handshake sequence around first mismatch.

3. Correlate assertion failures with waveform and intent checkpoints.

4. Separate setup/config issues from true design intent violations.

5. Run one hypothesis branch at a time and record disproof evidence.

6. Apply minimal fix and validate on local and suite-level LPV runs.

Artifacts to collect

• Temporal handshake checker suite with protocol assertions, timeout diagnostics, and scenario-wise latency histograms.

• power-state transition log

• cross-domain boundary trace

• assertion failure bucket report

• post-fix regression closure summary

Decision memo template

LPV DECISION MEMO - Save/Restore Handshake Sequencing
symptom:
phase:
root cause:
fix:
validation:
owners: power controller owner, firmware/power management owner, low-power verification owner, SoC integration owner

Low-power verification deep dive

Retention closure requires proving end-to-end state lifecycle through save, off, and restore windows.

Concept diagram

RETENTION LIFECYCLE

save request -> state capture -> power off -> power on -> restore -> traffic resume

Metric graph

RETENTION STABILITY

restore mismatch       █████
save timing defects    ████
stable wake cycles     ███████

Metrics and artifacts to collect

• retention save/restore timing report

• pre/post state diff matrix

• multi-cycle retention stress summary

• state-loss bug trend by mode

Mini case study

A corruption issue persisted until retention checks compared multi-cycle state snapshots rather than single wake events.

Debug branches

• Track save acknowledgement against actual state capture.

• Validate restore completion before functional traffic resumes.

• Run repeated sleep/wake cycles to expose drift.

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.

Principal LPV review addendum

Save/Restore Handshake Sequencing should be reviewed as a transition integrity system, not just isolated checks.

Use Handshake protocol compliance rate, save-to-off and restore-to-functional timing margin, and timeout escape count. as alarm and Temporal handshake checker suite with protocol assertions, timeout diagnostics, and scenario-wise latency histograms. as proof.

Retention closure requires proving save, off, and restore phases as one lifecycle with explicit handshake timing. Closure quality comes from reproducible evidence and explicit owners.