The unplug sweep dropped a pad the instant its active_mask bit read
clear — but a pad teardown is a whole PnP device removal (system-wide
device-change broadcasts, and on re-create a full hidclass
re-enumeration), so a client-side mask glitch of a few state frames
cycled real devnodes. The sweep now drops a pad only after its bit has
stayed clear for 300 ms; a bit that returns inside the grace disarms it.
A real unplug tears down one grace later, which nobody observes — the
pad already went quiet. Lands once in PadSlots, so every backend
(uinput/uhid/XUSB/UMDF) inherits it.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>