Root Cause Closure and FA Handoff: Inputs and Outputs

Inputs and outputs contract

Inputs and Outputs for Root Cause Closure and FA Handoff is anchored on Closure quality measured by root-cause confidence, mitigation durability, and FA turnaround from sample request to actionable evidence.. Convert observed behavior into mechanism-backed and owner-bound actions.

INPUTS
  - board and fixture configuration state
  - firmware revision and boot arguments
  - corner conditions (V/F/T) and workload window
  - instrumentation profile and trace coverage assumptions

OUTPUTS
  - evidence-backed root-cause class
  - owner-signed mitigation proposal
  - replay validation matrix and rollback triggers
  - release recommendation

Ownership split

OWNERSHIP LAYERS - Root Cause Closure and FA Handoff

+----------------------+--------------------------------+--------------------------------+
| Team                 | Primary responsibility         | Closure artifact               |
+----------------------+--------------------------------+--------------------------------+
| failure analysis owner | hypothesis map and execution     | triage decision log            |
| silicon bring-up lead | stage behavior and software proof | boot/trace evidence packet     |
| design and RTL owner | replay matrix and risk closure    | signoff memo + rollback gates  |
+----------------------+--------------------------------+--------------------------------+

Silicon bring-up deep dive

Triage quality is measured by how quickly teams converge from symptom to proven root-cause class with minimal collateral churn.

Concept diagram

TRIAGE CONVERGENCE

symptom -> classify -> isolate -> prove -> bounded fix -> replay

Metric graph

TRIAGE EFFECTIVENESS

wide speculative edits   ██████
classified bounded fixes █████████

Metrics and artifacts to collect

• time-to-classification

• first-failure artifact completeness

• hypothesis branch conversion rate

• post-fix recurrence trend

Mini case study

Intermittent field-like failures closed faster once teams forced one-variable branch tests and owner-tagged evidence packets.

Debug branches

• Preserve first-failure state before reruns.

• Use disproof-oriented experiments to collapse cause tree quickly.

• Promote fixes only after recurrence tracking windows pass.

Senior review question

Ask: what is the first failing boundary, which artifact proves it, and who owns bounded closure?

Key takeaways

• Tie every bring-up claim to one reproducible setup state and one proving artifact.

• Prefer bounded fixes with clear owner and rollback trigger over broad multi-variable edits.

Common pitfalls

• Running parallel uncontrolled experiments and losing causality.

• Declaring closure without replaying across representative corners.

• Escalating severity before bench/setup hypotheses are disproven.

Handoff explanation

Inputs should include board state, firmware hash, environment corner, and instrumentation profile.

Outputs should include owner-signed mitigation proposal and validation boundaries.