kern/56739: Hang during boot since recent USB changes

[gson%gson.org@localhost (Andreas Gustafsson)]

>Number:         56739
>Category:       kern
>Synopsis:       Hang during boot since recent USB changes
>Confidential:   no
>Severity:       serious
>Priority:       high
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Fri Mar 04 15:55:00 +0000 2022
>Originator:     Andreas Gustafsson
>Release:        NetBSD-current, source date 2022.03.03.06.12.11
>Organization:
  
>Environment:
System: NetBSD
Architecture: i386
Machine: i386
>Description:

My NetBSD-current testbed running on a physical i386 laptop hangs
while booting the INSTALL kernel, after printing the line

  [   3.4662759] ehci0: handing over full speed device on port 4 to uhci1

The device being handed over is an ualea(4).

The last known working version is source date 2022.03.02.19.32.15, and
the first known broken one is 2022.03.03.06.12.11.  I have started an
automated bisection to narrow this down further.

Logs are at

  https://www.gson.org/netbsd/bugs/build/i386-laptop/commits-2022.03.html#2022.03.03.06.12.11

>How-To-Repeat:

>Fix: