usb/175731: detaching USB keyboard freezes other USB keyboards

[Norbert Koch]

>Number:         175731
>Category:       usb
>Synopsis:       detaching USB keyboard freezes other USB keyboards
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    freebsd-usb
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Thu Jan 31 14:10:00 UTC 2013
>Closed-Date:
>Last-Modified:
>Originator:     Norbert Koch
>Release:        9.0
>Organization:
>Environment:
FreeBSD  9.0-RELEASE-p3 FreeBSD 9.0-RELEASE-p3 #0: Thu Jan 24 16:31:49 CET 2013     root at entw-pr2.demig.intra:/usr/home/nk/src/kernel/src/sys/EMBEDDED_USBKBD_ONLY  i386
>Description:
My kernel is compiled without support for atkbd. I only use USB keyboards.

Attaching is fine but when detaching, any of the keyboards - I tried up to three - the other keyboards freeze. If I attach the keyboard again the other keyboards
unfreeze and work as before.

The problem has something to do with devd.
Detaching works without problems in single user mode or with devd not running.
As long as dev does not run *during* detaching things seem to be ok too.

Commenting out usb keyboard related entries in /etc/devd.conf
or /etc/devd/usb.conf does not help.
Commenting out syscons_setkeyboard in /etc/rc.d/syscons does not help either.
>How-To-Repeat:
Attach two USB keyboards.
Detach any of them.
The still connected keyboards freezes.
Reconnect other keyboard.
Both keyboards work.
>Fix:


>Release-Note:
>Audit-Trail:
>Unformatted: