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Low Power / UPF · All levels

Power State Verification: Worked Example

Worked Example for Power State Verification.

Worked example

Worked Example for Power State Verification focuses on state transition coverage, illegal-transition hits, and reset-after-wakeup pass rate. The goal is to link observed behavior to power-intent mechanism, ownership, and release risk.

A nightly regression flags state transition coverage, illegal-transition hits, and reset-after-wakeup pass rate. The correct approach is to freeze transition context, verify policy intent on the failing crossing, and then apply a minimal fix with full LP regression discipline.

Transition sequence under review

diagram
STATE TRANSITIONS — Power State Verification

ON  --save-->  RETENTION  --off-->  OFF
 ^               |                    |
 |               +----restore<--------+
 +--------------------power_up--------+

Guard checks:
  - isolation asserted before OFF
  - restore before functional traffic
  - reset policy consistent with retained state

State transition test matrix

diagram
STATE TEST MATRIX

from  to   RUN   RETENTION   OFF
RUN         -     test        test
RETENTION   test  -           test
OFF         test  test        -

Cover legal transitions and illegal rejection behavior.

  1. Capture failing waveform interval with power-state markers.

  2. Tag domain states and policy controls at failure time.

  3. Cross-check expected policy in UPF against observed behavior.

  4. Compare against power-state coverage report, transition assertions, and scenario matrix.

  5. Choose one reversible fix and define regression blast radius before patching.

Did the fix hold?

diagram
BEFORE / AFTER FIX — Power State Verification

metric quality
  ^
  |                       o target region
  |                 o post-fix + regression
  |            o
  |      o failing baseline
  +----------------------------------------> iteration
      sequence audit   policy fix   full re-run

Low-power deep dive

Transition-centric verification closes LP risk better than active-mode-centric regressions.

Concept diagram

diagram
VERIFY LOOP

transition matrix -> simulation + formal -> coverage -> closure

Metric graph

diagram
COVERAGE CLOSURE

state transitions covered   ███████████
isolation activation        █████████
retention restore paths     ████████

Reports and artifacts

  • state coverage

  • formal LP properties

  • isolation coverage

  • LP bug triage dashboard

Mini case study

Coverage looked high, but one untested OFF->RUN transition hid a restore race.

Debug branches

  • Rank by transition criticality

  • Correlate PMU logs with failures

  • Escalate unproven properties

Senior review question

Ask: what transition evidence proves this topic is closed, and which owner signs it?

Key takeaways

  • State transition context must accompany every low-power metric claim.

  • Intent changes require simulation, formal, and implementation re-validation.

Common pitfalls

  • Comparing results from mismatched UPF revisions.

  • Assuming static checks replace transition validation.

  • Shipping with aged waivers and unclear ownership.

Execution drill pack 1

Use this pack to rehearse low-power closure on low-power/low-power-verification/power-state-verification/worked-example: transition framing, policy ownership, implementation evidence, and release confidence.

Transition checklist

  • State transition explicitly named with legal source/target states.

  • Crossing and domain ownership are mapped and agreed.

  • Policy controls are traced to always-on source logic.

  • Waveform bookmarks align controls with state timestamps.

Review prompts

  1. Which policy object is first to deviate from intent?

  2. Which owner can apply the smallest reversible fix?

  3. What regression matrix proves no collateral damage?

  4. Which waiver conditions would still block release?

Evidence capsule

diagram
LP EVIDENCE CAPSULE 1

PATH: low-power/low-power-verification/power-state-verification/worked-example
STATE WINDOW: <from -> to>
POLICY OBJECT: <isolation / retention / shifter / switch>
OWNER: <name>
PRIMARY ARTIFACT: <report/waveform/formal result>
RELEASE DECISION: <close / bounded waiver / escalate>

Execution drill pack 2

Use this pack to rehearse low-power closure on low-power/low-power-verification/power-state-verification/worked-example: transition framing, policy ownership, implementation evidence, and release confidence.

Transition checklist

  • State transition explicitly named with legal source/target states.

  • Crossing and domain ownership are mapped and agreed.

  • Policy controls are traced to always-on source logic.

  • Waveform bookmarks align controls with state timestamps.

Review prompts

  1. Which policy object is first to deviate from intent?

  2. Which owner can apply the smallest reversible fix?

  3. What regression matrix proves no collateral damage?

  4. Which waiver conditions would still block release?

Evidence capsule

diagram
LP EVIDENCE CAPSULE 2

PATH: low-power/low-power-verification/power-state-verification/worked-example
STATE WINDOW: <from -> to>
POLICY OBJECT: <isolation / retention / shifter / switch>
OWNER: <name>
PRIMARY ARTIFACT: <report/waveform/formal result>
RELEASE DECISION: <close / bounded waiver / escalate>

Execution drill pack 3

Use this pack to rehearse low-power closure on low-power/low-power-verification/power-state-verification/worked-example: transition framing, policy ownership, implementation evidence, and release confidence.

Transition checklist

  • State transition explicitly named with legal source/target states.

  • Crossing and domain ownership are mapped and agreed.

  • Policy controls are traced to always-on source logic.

  • Waveform bookmarks align controls with state timestamps.

Review prompts

  1. Which policy object is first to deviate from intent?

  2. Which owner can apply the smallest reversible fix?

  3. What regression matrix proves no collateral damage?

  4. Which waiver conditions would still block release?

Evidence capsule

diagram
LP EVIDENCE CAPSULE 3

PATH: low-power/low-power-verification/power-state-verification/worked-example
STATE WINDOW: <from -> to>
POLICY OBJECT: <isolation / retention / shifter / switch>
OWNER: <name>
PRIMARY ARTIFACT: <report/waveform/formal result>
RELEASE DECISION: <close / bounded waiver / escalate>

Execution drill pack 4

Use this pack to rehearse low-power closure on low-power/low-power-verification/power-state-verification/worked-example: transition framing, policy ownership, implementation evidence, and release confidence.

Transition checklist

  • State transition explicitly named with legal source/target states.

  • Crossing and domain ownership are mapped and agreed.

  • Policy controls are traced to always-on source logic.

  • Waveform bookmarks align controls with state timestamps.

Review prompts

  1. Which policy object is first to deviate from intent?

  2. Which owner can apply the smallest reversible fix?

  3. What regression matrix proves no collateral damage?

  4. Which waiver conditions would still block release?

Evidence capsule

diagram
LP EVIDENCE CAPSULE 4

PATH: low-power/low-power-verification/power-state-verification/worked-example
STATE WINDOW: <from -> to>
POLICY OBJECT: <isolation / retention / shifter / switch>
OWNER: <name>
PRIMARY ARTIFACT: <report/waveform/formal result>
RELEASE DECISION: <close / bounded waiver / escalate>

Execution drill pack 5

Use this pack to rehearse low-power closure on low-power/low-power-verification/power-state-verification/worked-example: transition framing, policy ownership, implementation evidence, and release confidence.

Transition checklist

  • State transition explicitly named with legal source/target states.

  • Crossing and domain ownership are mapped and agreed.

  • Policy controls are traced to always-on source logic.

  • Waveform bookmarks align controls with state timestamps.

Review prompts

  1. Which policy object is first to deviate from intent?

  2. Which owner can apply the smallest reversible fix?

  3. What regression matrix proves no collateral damage?

  4. Which waiver conditions would still block release?

Evidence capsule

diagram
LP EVIDENCE CAPSULE 5

PATH: low-power/low-power-verification/power-state-verification/worked-example
STATE WINDOW: <from -> to>
POLICY OBJECT: <isolation / retention / shifter / switch>
OWNER: <name>
PRIMARY ARTIFACT: <report/waveform/formal result>
RELEASE DECISION: <close / bounded waiver / escalate>

Execution drill pack 6

Use this pack to rehearse low-power closure on low-power/low-power-verification/power-state-verification/worked-example: transition framing, policy ownership, implementation evidence, and release confidence.

Transition checklist

  • State transition explicitly named with legal source/target states.

  • Crossing and domain ownership are mapped and agreed.

  • Policy controls are traced to always-on source logic.

  • Waveform bookmarks align controls with state timestamps.

Review prompts

  1. Which policy object is first to deviate from intent?

  2. Which owner can apply the smallest reversible fix?

  3. What regression matrix proves no collateral damage?

  4. Which waiver conditions would still block release?

Evidence capsule

diagram
LP EVIDENCE CAPSULE 6

PATH: low-power/low-power-verification/power-state-verification/worked-example
STATE WINDOW: <from -> to>
POLICY OBJECT: <isolation / retention / shifter / switch>
OWNER: <name>
PRIMARY ARTIFACT: <report/waveform/formal result>
RELEASE DECISION: <close / bounded waiver / escalate>

Execution drill pack 7

Use this pack to rehearse low-power closure on low-power/low-power-verification/power-state-verification/worked-example: transition framing, policy ownership, implementation evidence, and release confidence.

Transition checklist

  • State transition explicitly named with legal source/target states.

  • Crossing and domain ownership are mapped and agreed.

  • Policy controls are traced to always-on source logic.

  • Waveform bookmarks align controls with state timestamps.

Review prompts

  1. Which policy object is first to deviate from intent?

  2. Which owner can apply the smallest reversible fix?

  3. What regression matrix proves no collateral damage?

  4. Which waiver conditions would still block release?

Evidence capsule

diagram
LP EVIDENCE CAPSULE 7

PATH: low-power/low-power-verification/power-state-verification/worked-example
STATE WINDOW: <from -> to>
POLICY OBJECT: <isolation / retention / shifter / switch>
OWNER: <name>
PRIMARY ARTIFACT: <report/waveform/formal result>
RELEASE DECISION: <close / bounded waiver / escalate>

Execution drill pack 8

Use this pack to rehearse low-power closure on low-power/low-power-verification/power-state-verification/worked-example: transition framing, policy ownership, implementation evidence, and release confidence.

Transition checklist

  • State transition explicitly named with legal source/target states.

  • Crossing and domain ownership are mapped and agreed.

  • Policy controls are traced to always-on source logic.

  • Waveform bookmarks align controls with state timestamps.

Review prompts

  1. Which policy object is first to deviate from intent?

  2. Which owner can apply the smallest reversible fix?

  3. What regression matrix proves no collateral damage?

  4. Which waiver conditions would still block release?

Evidence capsule

diagram
LP EVIDENCE CAPSULE 8

PATH: low-power/low-power-verification/power-state-verification/worked-example
STATE WINDOW: <from -> to>
POLICY OBJECT: <isolation / retention / shifter / switch>
OWNER: <name>
PRIMARY ARTIFACT: <report/waveform/formal result>
RELEASE DECISION: <close / bounded waiver / escalate>

Execution drill pack 9

Use this pack to rehearse low-power closure on low-power/low-power-verification/power-state-verification/worked-example: transition framing, policy ownership, implementation evidence, and release confidence.

Transition checklist

  • State transition explicitly named with legal source/target states.

  • Crossing and domain ownership are mapped and agreed.

  • Policy controls are traced to always-on source logic.

  • Waveform bookmarks align controls with state timestamps.

Review prompts

  1. Which policy object is first to deviate from intent?

  2. Which owner can apply the smallest reversible fix?

  3. What regression matrix proves no collateral damage?

  4. Which waiver conditions would still block release?

Evidence capsule

diagram
LP EVIDENCE CAPSULE 9

PATH: low-power/low-power-verification/power-state-verification/worked-example
STATE WINDOW: <from -> to>
POLICY OBJECT: <isolation / retention / shifter / switch>
OWNER: <name>
PRIMARY ARTIFACT: <report/waveform/formal result>
RELEASE DECISION: <close / bounded waiver / escalate>

Execution drill pack 10

Use this pack to rehearse low-power closure on low-power/low-power-verification/power-state-verification/worked-example: transition framing, policy ownership, implementation evidence, and release confidence.

Transition checklist

  • State transition explicitly named with legal source/target states.

  • Crossing and domain ownership are mapped and agreed.

  • Policy controls are traced to always-on source logic.

  • Waveform bookmarks align controls with state timestamps.

Review prompts

  1. Which policy object is first to deviate from intent?

  2. Which owner can apply the smallest reversible fix?

  3. What regression matrix proves no collateral damage?

  4. Which waiver conditions would still block release?

Evidence capsule

diagram
LP EVIDENCE CAPSULE 10

PATH: low-power/low-power-verification/power-state-verification/worked-example
STATE WINDOW: <from -> to>
POLICY OBJECT: <isolation / retention / shifter / switch>
OWNER: <name>
PRIMARY ARTIFACT: <report/waveform/formal result>
RELEASE DECISION: <close / bounded waiver / escalate>

Execution drill pack 11

Use this pack to rehearse low-power closure on low-power/low-power-verification/power-state-verification/worked-example: transition framing, policy ownership, implementation evidence, and release confidence.

Transition checklist

  • State transition explicitly named with legal source/target states.

  • Crossing and domain ownership are mapped and agreed.

  • Policy controls are traced to always-on source logic.

  • Waveform bookmarks align controls with state timestamps.

Review prompts

  1. Which policy object is first to deviate from intent?

  2. Which owner can apply the smallest reversible fix?

  3. What regression matrix proves no collateral damage?

  4. Which waiver conditions would still block release?

Evidence capsule

diagram
LP EVIDENCE CAPSULE 11

PATH: low-power/low-power-verification/power-state-verification/worked-example
STATE WINDOW: <from -> to>
POLICY OBJECT: <isolation / retention / shifter / switch>
OWNER: <name>
PRIMARY ARTIFACT: <report/waveform/formal result>
RELEASE DECISION: <close / bounded waiver / escalate>

Execution drill pack 12

Use this pack to rehearse low-power closure on low-power/low-power-verification/power-state-verification/worked-example: transition framing, policy ownership, implementation evidence, and release confidence.

Transition checklist

  • State transition explicitly named with legal source/target states.

  • Crossing and domain ownership are mapped and agreed.

  • Policy controls are traced to always-on source logic.

  • Waveform bookmarks align controls with state timestamps.

Review prompts

  1. Which policy object is first to deviate from intent?

  2. Which owner can apply the smallest reversible fix?

  3. What regression matrix proves no collateral damage?

  4. Which waiver conditions would still block release?

Evidence capsule

diagram
LP EVIDENCE CAPSULE 12

PATH: low-power/low-power-verification/power-state-verification/worked-example
STATE WINDOW: <from -> to>
POLICY OBJECT: <isolation / retention / shifter / switch>
OWNER: <name>
PRIMARY ARTIFACT: <report/waveform/formal result>
RELEASE DECISION: <close / bounded waiver / escalate>

Execution drill pack 13

Use this pack to rehearse low-power closure on low-power/low-power-verification/power-state-verification/worked-example: transition framing, policy ownership, implementation evidence, and release confidence.

Transition checklist

  • State transition explicitly named with legal source/target states.

  • Crossing and domain ownership are mapped and agreed.

  • Policy controls are traced to always-on source logic.

  • Waveform bookmarks align controls with state timestamps.

Review prompts

  1. Which policy object is first to deviate from intent?

  2. Which owner can apply the smallest reversible fix?

  3. What regression matrix proves no collateral damage?

  4. Which waiver conditions would still block release?

Evidence capsule

diagram
LP EVIDENCE CAPSULE 13

PATH: low-power/low-power-verification/power-state-verification/worked-example
STATE WINDOW: <from -> to>
POLICY OBJECT: <isolation / retention / shifter / switch>
OWNER: <name>
PRIMARY ARTIFACT: <report/waveform/formal result>
RELEASE DECISION: <close / bounded waiver / escalate>

Principal LP review addendum

Verification environments must drive realistic power-mode transitions and check protocol behavior across ON/OFF/RETENTION states.

Metric: state transition coverage, illegal-transition hits, and reset-after-wakeup pass rate

Practice this lesson