Power State Tables (PST) and UPF Intent Consistency: Design Space

Design space exploration

For Power State Tables (PST) and UPF Intent Consistency, teams balance safety, closure speed, and simulation or debug cost.

Option A - conservative

• Conservative controls: helps strong safety and clarity

• Risk: higher setup and runtime overhead

• Validate with: new LPV program bring-up

Option B - balanced

• Balanced controls: helps good closure velocity

• Risk: needs disciplined review

• Validate with: shared platform verification

Option C - aggressive

• Aggressive optimization: helps lower overhead

• Risk: higher corner-case risk

• Validate with: mature flows with strong telemetry

Option D - refactor

• Refactor path: helps long-term robustness

• Risk: migration cost

• Validate with: legacy LPV debt cleanup

DESIGN SPACE - Power State Tables (PST) and UPF Intent Consistency
coverage depth <-> simulation/runtime cost <-> debug clarity <-> residual risk

Design pitfalls

• Optimizing runtime before proving intent-correctness boundaries.

• Adding checks without ownership of closure and triage workflow.

Low-power verification deep dive

Power-state correctness is a protocol contract: legal transitions, robust sequencing, and safe concurrent event handling.

Concept diagram

PST CONTROL LOOP

state request -> legality check -> handshake sequencing -> mode entry -> monitored exit

Metric graph

STATE RISK MIX

illegal transitions     ██████
sequence race bugs      █████
stable mode paths       ████████

Metrics and artifacts to collect

• PST legality matrix

• illegal transition histogram

• entry/exit handshake coverage

• mode sequencing anomaly log

Mini case study

A sporadic low-power failure closed only after proving a wake-versus-thermal race in PMU transition sequencing.

Debug branches

• Validate legal state graph first.

• Stress concurrent control events and asynchronous wakeups.

• Bind fixes to explicit transition and owner contracts.

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

Power State Tables (PST) and UPF Intent Consistency should be reviewed as a transition integrity system, not just isolated checks.

Use PST legality closure (allowed states vs observed states) and count of state-encoding mismatches between UPF, firmware tables, and RTL control logic. as alarm and PST intent traceability matrix linking UPF states to RTL control points, firmware enums, and per-state assertion bundles. as proof.

Power-state verification is a protocol verification problem: legal transitions, ordering contracts, and corner-case concurrency. Closure quality comes from reproducible evidence and explicit owners.