fix(hid): handle analytics-only keyboards in host_switch_targets

[sam-phinizy]

Summary

• host_switch_targets silently fails on keyboards whose Easy-Switch controls are analytics-only (divertable=false). The keyboard departs before switch_linked_hosts can probe the device, so the DeviceNotFound error propagates via ? and the target loop is never reached — the mouse never receives its setCurrentHost command.
• When the keyboard is unreachable (already departed), the function now falls through to switch_targets_directly, which opens each target's own channel and switches it independently.

Changes

• openlogi-hid (crates/openlogi-hid/src/session/host_switch.rs):
  • switch_linked_hosts now catches DeviceNotFound during keyboard preparation and falls through to target-only switching instead of aborting.
  • New helper switch_targets_directly opens each target's own HID++ channel and sends setCurrentHost without relying on the keyboard's channel.

Testing

Verified on MX Keys S for Mac (B37C, firmware 82.1.12) + MX Master 4 (B042) over Bolt receiver on macOS. Not runtime-tested on hardware for Linux or Windows.

OPENLOGI_LOG=debug trace before fix:

keyboard host switch failed error=HID++ protocol error: opening host-change device: DeviceNotFound route=slot 6 host=1
host switch session ended error=HID++ protocol error: opening keyboard device: DeviceNotFound

After fix:

keyboard unreachable; switching targets only error=HID++ protocol error: opening host-change device: DeviceNotFound route=slot 6 host=1

Mouse successfully followed the keyboard.

Fixes a race condition affecting all keyboards that report divertable=false analytics=true for their host switch controls (CIDs 0x00d1–0x00d3).

[greptile-apps]

Greptile Summary

The PR narrows the analytics-only keyboard fallback so ordinary HID++ timeouts no longer count as confirmed keyboard departure.

• Propagates preparation timeouts instead of directly switching linked targets.
• Retains target-only switching for errors that specifically indicate an unreachable keyboard.
• Preserves host-slot validation before any linked target moves.

Confidence Score: 5/5

The PR appears safe to merge.

No blocking failure remains.

Important Files Changed

Filename	Overview
crates/openlogi-hid/src/session/host_switch.rs	Narrows the direct-target fallback to explicit unreachable-device failures, resolving both previously reported overbroad fallback cases.

Flowchart

%%{init: {'theme': 'neutral'}}%%
flowchart TD
  A[Prepare keyboard host change] --> B{Result}
  B -->|Success| C[Switch linked targets]
  C --> D[Switch keyboard last]
  B -->|Device unreachable| E[Switch targets directly]
  B -->|Timeout or validation error| F[Propagate error without switching targets]

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_{Reviews (4): Last reviewed commit: "fix(hid): remove TimedOut from departure..." | Re-trigger Greptile}