feat(cardwired): refresh on thunderbolt event

[luytan]

Description

Refresh cardwire gpu list on thunderbolt event (for eGPUs)

Fixes # (issue)

Checklist:

• My code follows the style guidelines of this project (cargo fmt)
• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the mdBook documentation
• My changes generate no new warnings (clippy/clang)
• New and existing unit tests pass locally with my changes (either use nix flake check or wait for the ci)

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ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Repository UI

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Run ID: 1def50d8-d34c-4f34-9b7d-09855f5719b5

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Reviewing files that changed from the base of the PR and between d67c8cc and 52da1d4.

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• crates/cardwire-daemon/src/tasks/monitor_udev.rs

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📝 Summary

Summary by CodeRabbit

• New Features

  • GPU state now refreshes automatically when Thunderbolt devices are added, removed, or changed.
  • GPU state continues to refresh when PCI devices are connected or disconnected.

• Bug Fixes

  • Improved device-change monitoring so updates from PCI and Thunderbolt hardware are handled concurrently.
  • Device refresh failures are logged without interrupting ongoing hardware monitoring.

Walkthrough

The udev monitor now watches both PCI and Thunderbolt subsystems. Matching events trigger GPU refreshes. The task polls both monitors with tokio::select!, logs refresh failures, and clears each readiness guard.

Changes

Udev GPU monitoring

Layer / File(s)	Summary
Dual-subsystem event monitoring crates/cardwire-daemon/src/tasks/monitor_udev.rs	monitor_pci_changes creates separate PCI and Thunderbolt monitors and polls both with tokio::select!. PCI bind/unbind and Thunderbolt add/remove/change events call debug.refresh_gpu(). Refresh failures are logged, and readiness guards are cleared.

Priority: ⬇️ Low

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

Change: Feature

Sequence Diagram(s)

sequenceDiagram
  participant PCI_AsyncFd
  participant Thunderbolt_AsyncFd
  participant monitor_pci_changes
  participant DebugInterface
  PCI_AsyncFd->>monitor_pci_changes: PCI bind or unbind event
  monitor_pci_changes->>DebugInterface: refresh_gpu()
  Thunderbolt_AsyncFd->>monitor_pci_changes: Thunderbolt add, remove, or change event
  monitor_pci_changes->>DebugInterface: refresh_gpu()

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Merge Risk: ⚪ Minimal · up to 52da1

The reviewed readiness changes are mergeable with no confirmed current risk.

🚥 Pre-merge checks | ✅ 4

✅ Passed checks (4 passed)

Check name	Status	Explanation
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.
Title check	✅ Passed	The title clearly identifies the main change: refreshing the CardWired GPU list on Thunderbolt events.
Description check	✅ Passed	The description explains the change and its eGPU motivation. It includes the required checklist, with most items completed. The issue reference remains a placeholder, and documentation changes are mar…

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Actionable comments posted: 1

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• 🪄 Fix CodeRabbit comments on this PR

🤖 Prompt to fix review comments

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Inline comments:
In `@crates/cardwire-daemon/src/tasks/monitor_udev.rs`:
- Line 16: Propagate readiness errors in both monitor branches by replacing the
conditional guard pattern around guard_res with error propagation before
checking guard.ready().is_readable(). Apply this in the udev and Thunderbolt
monitor branches so monitor_udev_future receives persistent AsyncFd::readable()
failures instead of retrying.

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ℹ️ Review info

⚙️ Run configuration

Configuration used: Repository UI

Review profile: ASSERTIVE

Plan: Advanced

Run ID: 982f1310-97a5-4172-a239-f5287a09d49d

📥 Commits

Reviewing files that changed from the base of the PR and between aefc184 and d67c8cc.

📒 Files selected for processing (1)

• crates/cardwire-daemon/src/tasks/monitor_udev.rs

Included review availability: Your plan provides up to 2 included reviews per hour; 1 remains after this review.