fix: Introduce delay after power Off in dpf handling.

[abvarshney-nv]

Due to enqueue based event handling, On is triggered immediately after Off while chassis is not able to process Off completely. So this time delay is needed.

Related issues

Type of Change

• Add - New feature or capability
• Change - Changes in existing functionality
• Fix - Bug fixes
• Remove - Removed features or deprecated functionality
• Internal - Internal changes (refactoring, tests, docs, etc.)

Breaking Changes

• This PR contains breaking changes

Testing

• Unit tests added/updated
• Integration tests added/updated
• Manual testing performed
• No testing required (docs, internal refactor, etc.)

Additional Notes

[coderabbitai]

Summary by CodeRabbit

• Bug Fixes
  • Improved reboot handling by consistently applying the configured power-transition delay.
  • Updated reboot progress behavior so completion proceeds correctly after the device is powered on and the required delay has elapsed.
  • Clarified status reporting while waiting for the power transition.

Walkthrough

The DPF reboot handler now applies the configured power-transition delay unconditionally through the timestamp-based wait check before completing the On transition. Its transition documentation was updated to reflect the resulting WaitingForReady path.

Changes

DPF reboot state machine

Layer / File(s)	Summary
Apply power-transition delay consistently crates/machine-controller/src/handler/dpf.rs	The On transition documentation now describes waiting for the observed power state and configured delay. The handler removes the initial-On special case and returns the existing wait outcome whenever the timestamp-based delay gate is active.

Estimated code review effort: 2 (Simple) | ~10 minutes

Possibly related PRs

• NVIDIA/infra-controller#3845: Updates DPF reboot tests around persisted On intent and Power(On) command ordering, which relates to this PR’s reboot timing behavior.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly states the main change: adding a post-off delay in DPF handling.
Description check	✅ Passed	The description matches the change and explains why the off-to-on delay is needed.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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[coderabbitai]

Actionable comments posted: 1

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Verify each finding against current code. Fix only still-valid issues, skip the
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Inline comments:
In `@crates/machine-controller/src/handler/dpf.rs`:
- Around line 328-333: Scope the wait gate around super::wait to the
PerformPowerOperation::On branch in the handler’s operation match, so only On
transitions return the waiting outcome during the Off→On delay. Ensure the Off
branch reads the current power state and can issue ForceOff without being
blocked by this delay.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

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ℹ️ Review info

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📥 Commits

Reviewing files that changed from the base of the PR and between 862b66a and 60e9046.

📒 Files selected for processing (1)

• crates/machine-controller/src/handler/dpf.rs

[bcavnvidia]

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