usb seems hung

My usb subsystem seems to be hung.

When I plug a usb memory stick into a usb port, nothing shows up in dmesg and
there are no devices listed in /dev/da*

"usbconfig dump_all_desc" just sits there, as if hung

camcontrol devlist shows only disks:
# camcontrol devlist
<TSSTcorp CD-RW   TS-H292B DE03>   at scbus1 target 0 lun 0 (cd0,pass0)
<ST1000DM003-1CH162 CC49>          at scbus4 target 0 lun 0 (pass1,ada0)
<ST3250820NS 3.AEG>                at scbus5 target 0 lun 0 (pass2,ada1)

13.5-RELEASE-p10 FreeBSD 13.5-RELEASE-p10 GENERIC amd64

Any ideas what might be going on and how to resurrect without a reboot?

Gary