DenseChip

Low Power / UPF · All levels

Mode Transition IR: Debug Playbook

Debug Playbook for Mode Transition IR.

Debug playbook

Debug Playbook for Mode Transition IR focuses on transient IR droop, wake-up rail settling time, and brownout margin. The goal is to link observed behavior to power-intent mechanism, ownership, and release risk.

Low-power debug is timeline-centric. Find the first transition deviation, then trace policy and ownership from intent to implementation.

Root-cause tree

diagram
ROOT-CAUSE TREE — Mode Transition IR

transient IR droop, wake-up rail settling time, and brownout margin regressed
        |
   reproducible in same sequence?
     /                \
   no                  yes
   |                    |
stimulus drift      intent mismatch or
testbench issue     implementation bug
 /      \              |
power    checker     crossing/strategy audit
state    model       + waveform timeline

  1. Freeze failing RTL, UPF, PMU sequence, and implementation tags.

  2. Identify the first failing transition and affected crossing.

  3. Classify issue: policy binding, sequencing, or physical realization.

  4. Prove mechanism with one reduced reproducer.

  5. Patch smallest owner-controlled fix.

  6. Re-run focused checks then full LP regression matrix.

Review memo template

diagram
LOW-POWER REVIEW MEMO — PD & Power Grid Integration / Mode Transition IR

1. Symptom
   - Watched metric: transient IR droop, wake-up rail settling time, and brownout margin
   - Failing transition: <state_from -> state_to>
   - Failing crossing/domain: <source -> destination>
   - Revision tags: <RTL, UPF, PMU sequence, implementation>

2. Mechanism hypothesis
   - Primary mechanism: Transitioning domains ON/OFF shifts current demand rapidly; transient IR analysis verifies rails remain within functional tolerance.
   - Competing hypotheses: <intent mismatch, sequence bug, physical issue>
   - Missing evidence: <coverage, waveform bookmark, signoff report>

3. Proposed action
   - Minimal reversible change: <policy/sequence/implementation patch>
   - Expected movement: <coverage, violation count, transition pass rate>
   - Regression risk: wake-up timing, X-leak, IR droop, retention stability

4. Signoff
   - Re-run artifact: dynamic IR report, rail waveform captures, and mode transition log
   - Required owners: signoff owner, PD power owner, PMU owner
   - Final decision: fix, bounded waiver, or escalation

Low-power deep dive

Mode transition IR and ownership clarity determine tapeout confidence.

Concept diagram

diagram
GRID + TRANSITIONS

domain partition -> staged wake -> transient IR -> signoff gate

Metric graph

diagram
TRANSIENT DROOP TREND

baseline       ███████
after staging  ████
after tuning   ██

Reports and artifacts

  • domain grid report

  • dynamic IR analysis

  • LP signoff dashboard

  • handoff owner matrix

Mini case study

Dynamic IR during wake-up, not static IR, was the true blocker for release.

Debug branches

  • Inspect transition waveforms

  • Check PMU schedule alignment

  • Escalate aged waivers

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/pd-power-integration/mode-transition-ir/debug-playbook: 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/pd-power-integration/mode-transition-ir/debug-playbook
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/pd-power-integration/mode-transition-ir/debug-playbook: 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/pd-power-integration/mode-transition-ir/debug-playbook
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/pd-power-integration/mode-transition-ir/debug-playbook: 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/pd-power-integration/mode-transition-ir/debug-playbook
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/pd-power-integration/mode-transition-ir/debug-playbook: 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/pd-power-integration/mode-transition-ir/debug-playbook
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/pd-power-integration/mode-transition-ir/debug-playbook: 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/pd-power-integration/mode-transition-ir/debug-playbook
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/pd-power-integration/mode-transition-ir/debug-playbook: 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/pd-power-integration/mode-transition-ir/debug-playbook
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/pd-power-integration/mode-transition-ir/debug-playbook: 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/pd-power-integration/mode-transition-ir/debug-playbook
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/pd-power-integration/mode-transition-ir/debug-playbook: 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/pd-power-integration/mode-transition-ir/debug-playbook
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/pd-power-integration/mode-transition-ir/debug-playbook: 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/pd-power-integration/mode-transition-ir/debug-playbook
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/pd-power-integration/mode-transition-ir/debug-playbook: 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/pd-power-integration/mode-transition-ir/debug-playbook
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/pd-power-integration/mode-transition-ir/debug-playbook: 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/pd-power-integration/mode-transition-ir/debug-playbook
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/pd-power-integration/mode-transition-ir/debug-playbook: 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/pd-power-integration/mode-transition-ir/debug-playbook
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/pd-power-integration/mode-transition-ir/debug-playbook: 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/pd-power-integration/mode-transition-ir/debug-playbook
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

Transitioning domains ON/OFF shifts current demand rapidly; transient IR analysis verifies rails remain within functional tolerance.

Metric: transient IR droop, wake-up rail settling time, and brownout margin

Practice this lesson