kern/53400: Assert failure in usb_transfer_complete()

[phil%netbsd.org@localhost]

>Number:         53400
>Category:       kern
>Synopsis:       Assert failure in  usb_transfer_complete()
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Tue Jun 26 18:20:00 +0000 2018
>Originator:     Phil Nelson
>Release:        8.99.20
>Organization:
>Environment:
NetBSD steelhead.pcnelson.net 8.99.20 NetBSD 8.99.20 (STEELHEAD) #1: Tue Jun 26 09:29:27 PDT 2018  phil%steelhead.pcnelson.net@localhost:/home/phil/netbsd/src/sys/arch/amd64/compile/STEELHEAD amd64

Machines is a Dell optiplex 3020, quad core Intel(R) Core(TM) i5-4590, 8GB of memory
>Description:
Jun 26 10:36:21 steelhead /netbsd: [ 3654.8489932] panic: kernel diagnostic assertion "xfer->ux_state == XFER_ONQU" failed: file "../../../../dev/usb/usbdi.c", line 915 xfer->ux_state: 85
Jun 26 10:36:21 steelhead /netbsd: [ 3654.8489932] cpu1: Begin traceback...
Jun 26 10:36:21 steelhead /netbsd: [ 3654.8489932] vpanic() at netbsd:vpanic+0x16f
Jun 26 10:36:21 steelhead /netbsd: [ 3654.8489932] ch_voltag_convert_in() at netbsd:ch_voltag_convert_in
Jun 26 10:36:21 steelhead /netbsd: [ 3654.8489932] usb_transfer_complete() at netbsd:usb_transfer_complete+0x291
Jun 26 10:36:21 steelhead /netbsd: [ 3654.8489932] xhci_abort_xfer() at netbsd:xhci_abort_xfer+0x137
Jun 26 10:36:21 steelhead /netbsd: [ 3654.8489932] usbd_ar_pi[ 3654.8489932] pe() at [ 3654.8489932] netbsd:usbd_ar_pipe+0x54
Jun 26 10:36:21 steelhead /netbsd: [ 3654.8489932] usbd_abort_pipe() at netbsd:usbd_abort_pipe+0x27
Jun 26 10:36:21 steelhead /netbsd: [ 3654.8489932] uhidev_detach() at netbsd:uhidev_detach+0x32
Jun 26 10:36:21 steelhead /netbsd: [ 3654.8489932] config_detach() at netbsd:config_detach+0x121
Jun 26 10:36:21 steelhead /netbsd: [ 3654.8489932] usb_disconnect_port() at netbsd:usb_disconnect_port+0xb8
Jun 26 10:36:21 steelhead /netbsd: [ 3654.8489932] uhub_detach() at netbsd:uhub_detach+0x7f
Jun 26 10:36:21 steelhead /netbsd: [ 3654.8489932] config_detach() at netbsd:config_detach+0x121
Jun 26 10:36:21 steelhead /netbsd: [ 3654.8589964] usb_disconnect_port() at netbsd:usb_disconnect_port+0xb8
Jun 26 10:36:21 steelhead /netbsd: [ 3654.8589964] uhub_explore() at netbsd:uhub_explore+0x221
Jun 26 10:36:21 steelhead /netbsd: [ 3654.8589964] usb_discover.isra.2() at netbsd:usb_discover.isra.2+0x67
Jun 26 10:36:21 steelhead /netbsd: [ 3654.8589964] usb_event_thread() at netbsd:usb_event_thread+0x7c
Jun 26 10:36:21 steelhead /netbsd: [ 3654.8589964] cpu1: End traceback...

>How-To-Repeat:
Using my KVM switch that does keyboard and mouse via USB.  A switch does
a disconnect from one machine and a connect to the next one.
>Fix: