usb/160436: ucom wedges machine on parity error ?

Poul-Henning Kamp phk at critter.freebsd.dk
Sat Sep 3 20:00:21 UTC 2011


>Number:         160436
>Category:       usb
>Synopsis:       ucom wedges machine on parity error ?
>Confidential:   no
>Severity:       serious
>Priority:       low
>Responsible:    freebsd-usb
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Sat Sep 03 20:00:20 UTC 2011
>Closed-Date:
>Last-Modified:
>Originator:     Poul-Henning Kamp
>Release:        FreeBSD 8.2-STABLE i386
>Organization:
>Environment:
FreeBSD shus.dc.freebsd.dk 8.2-STABLE FreeBSD 8.2-STABLE #0: Wed Aug 31 08:43:34 UTC 2011     root at hex-drift.freebsd.dk:/freebsd/obj/nanobsd.shus/freebsd/src/sys/NET4801  i386

	Soekris NET4801

>Description:

	I'm running Soekris NET4801 doing data collection, it has been
	running stable for years.

	Recently I added a USB-serial port running in raw mode
	at 300/7/EVEN

	The machine started freezing hard and recovered only when the
	watchdog kicked in.

	When frozen, there is no serial console reaction, no packet
	traffic and no signs of a panic message.

	I tried two different USB-serial dongles, one UPLCOM and
	one UFTDI, apart from a possibly slightly different frequency,
	no difference.

	Disabling the software on the USB serial port, made the freezes
	go away.

	I have now moved the parity check into software, running the
	port as 300/8/NONE instead, and the problem has not been seen
	since.

	Has anybody ever tested a parity error on a USB serial port ?

>How-To-Repeat:
	
>Fix:

	


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


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