After a USB re-enumeration the rtw89 radio can come back as a fresh DOWN
netdev, dropped from br0, while the still-running hostapd never notices and
never exits — so Restart=always never fires. hostapd_cli keeps answering
state=ENABLED off stale in-memory state, so the watchdog considered the AP
healthy and left it dark (observed 2026-07-05: AP down ~16:41 until manual
hostapd restart).
Add link_healthy(): require the netdev to be operstate=up and still a port of
its bridge, alongside the existing state=ENABLED check. That catches the wedged
case the control socket can't see.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Andreas WredeandClaude Opus 4.8
4117802f69