As far as I can tell, xhci(4) is hanging on "something" during early
boot (probably something uninitialized) that causes it to basically
never attach drives.
I only have one controller here, so it could be something special with
my device.
If I single user my machine and attach my storage array, probe/attach
works just fine. Leaving the USB3 array attached during a full boot
causes xhci(4) to become completely unresponsive and requires a reboot
to resolve.
I probably need someone who understand the early bits well enough to
know what things a driver can/cannot do prior to single-user mode.
https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=261912
sean
