[vdemonchy]

Summary

• A physical mode switch (XInput ↔ DS4 ↔ Switch ↔ HID) re-enumerates the controller over USB (remove + add). The single post-add poll can read the device mid-transition — openHID rides the ~1.5s udev uaccess race, and reader.Read/power_supply attrs may not be ready yet — so readHID returns a Stale read carrying the previous mode's battery, and nothing corrects it until the next poll tick (30–60s).
• Schedules short follow-up polls (settleDelays = {1s, 3s}) after each hotplug add via a new scheduleSettle helper feeding a buffered settleCh, so the settled value reaches both frontends within seconds. Daemon-only — the GNOME extension and COSMIC applet already mirror the state file.
• Non-blocking sends into a size-1 channel coalesce bursts of reconnects with no timer bookkeeping.

Test Plan

• go test ./cmd/cyclone2/ -run TestScheduleSettle -v — new unit tests (arms one timer per delay; simultaneous fires coalesce to one queued send)
• go test ./..., go build ./..., go vet ./... — clean (and go test -race clean)
• Manual (hardware): with the daemon running, flip the controller mode switch and confirm $XDG_RUNTIME_DIR/cyclone2-linux.json reflects the new mode/battery within a few seconds, not after a full poll interval

🤖 Generated with Claude Code