Two bugs in the firewire bus layer that affect all consumers (
if_fwip, sbp):
watchdog_clock was a static local in firewire_watchdog(), shared across
all firewire_comm instances. With two controllers (e.g. built-in +
Thunderbolt Display), both advance the same counter, so the second
controller's 15-second boot-time timeout guard expires prematurely.
fw_tl2xfer() released tlabel_lock before returning the xfer pointer.