Reset Sequencing: Pitfalls & Red Flags

Pitfalls and red flags

Pitfalls & Red Flags for Reset Sequencing focuses on domain bring-up order violations, dependency deadlocks, reset latency. The goal is to convert issue observations into mechanism-backed closure decisions.

• Two-flop synchronizer used for transactional bus crossing.

• Waiver approved without proving containment in stressed modes.

• Reset release checks skipped due to passing functional smoke tests.

• Reconvergence warnings ignored as 'tool noise' without replay.

• Dashboard green because of waivers, while critical risk remains.

Layer responsibility check

CDC/RDC OWNERSHIP LAYERS — Reset Sequencing

layer                 owns                            common failure
------------------    -----------------------------   -----------------------------
design intent         crossing architecture           wrong topology selected
protocol semantics    req/ack, fifo, ordering        liveness/deadlock bugs
reset behavior        assert/deassert sequencing      boot instability
analysis setup        tool rules + waivers            false confidence
signoff governance    risk acceptance + dashboard     stale critical waivers

CDC/RDC deep dive

Reset release ordering is a first-order reliability contract.

Concept diagram

RESET RELEASE FLOW

assert global -> clocks stable -> sync release per domain -> first transaction

Metric graph

BOOT STABILITY

passes per 1k boots: 920 -> 980 -> 999

Reports and artifacts

• reset dependency matrix

• RDC warning classes

• boot stress logs

• waiver aging

Mini case study

Domain B released before producer A was valid, causing rare startup deadlock.

Debug branches

• Correlate reset and clock timelines

• verify async assert/sync release

• exercise skewed release tests

Senior review question

Ask: what evidence proves this risk is closed for silicon, not just tool-clean?

Key takeaways

• State crossing class, assumptions, and owner with every issue.

• Run structural and dynamic regressions after each fix.

Common pitfalls

• Treating all warnings as equivalent risk.

• Waiving issues without containment evidence.

• Skipping reset and reconvergence stress after CDC fixes.

Principal CDC/RDC review addendum

Reset ordering enforces dependency contracts so control domains and memories become valid before downstream consumers execute.

Metric: domain bring-up order violations, dependency deadlocks, reset latency