usb/179505: Kernel detaches Arduino Leonardo (and similar) board umodem after the arduino boots

[Mike Meyer]

>Number:         179505
>Category:       usb
>Synopsis:       Kernel detaches Arduino Leonardo (and similar) board umodem after the arduino boots
>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:   Wed Jun 12 02:30:00 UTC 2013
>Closed-Date:
>Last-Modified:
>Originator:     Mike Meyer
>Release:        9.1-releng
>Organization:
Meyer Consulting
>Environment:
FreeBSD bhuda.mired.org 9.1-RELEASE-p3 FreeBSD 9.1-RELEASE-p3 #0 r250692M: Thu May 16 11:14:23 EDT 2013     root at bhuda.mired.org:/usr/src/sys/amd64/compile/BHUDA  amd64
>Description:
When the Arduino boards provide a umodem device to the host for programming and serial communications with the host from the user software (the software running after boot). The newest boards - starting with the Leonardo - also have the ability to provide a variety of HID devices at different endpoints. 

The older boards work fine. With the leonardo, the umodem device attaches as the board boots (or resets), and the /dev/ttyU* files are created for it. The device then detaches before or as the user code starts running, meaning the files vanish.

>How-To-Repeat:
Plug a leonardo board into a USB port on your machine. Reset it if needed. As it reboots (the L led will be blinking), you can see the /dev/tty* files appear. They will be gone after the reboot is finished.

>Fix:
I don't have a fix. The board can be programmed by hitting reset shortly before running avrdude (so for now, this is a low priority problem).

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