Legal and Illegal PST Transition Checks: Inputs and Outputs

Inputs and outputs contract

Inputs and Outputs for Legal and Illegal PST Transition Checks is anchored on Illegal transition escape rate, transition-checker latency to first error, and percentage of legal arcs exercised with pass/fail evidence.. Convert observations into mechanism-backed and owner-bound actions.

INPUTS
  - power-mode sequence and ownership context
  - seed, order, and configuration metadata
  - intent assumptions for transitions and crossings
  - assertion and coverage expectation envelope

OUTPUTS
  - evidence-backed failure classification
  - owner-signed mitigation proposal
  - validation matrix and rollback triggers
  - release recommendation

Ownership split

OWNERSHIP LAYERS - Legal and Illegal PST Transition Checks

+----------------------+--------------------------------+--------------------------------+
| Team                 | Primary responsibility         | Closure artifact               |
+----------------------+--------------------------------+--------------------------------+
| DV assertion owner | scenario intent and closure      | review rationale memo          |
| power controller RTL lead | transition and boundary contract | timeline + assertion packet    |
| firmware sequencing owner | regression signoff readiness     | validation matrix + risk note  |
+----------------------+--------------------------------+--------------------------------+

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.

Handoff explanation

Inputs should include mode sequence, domain status, and control ownership context.

Outputs should include deterministic reproducer and acceptance boundaries.