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Date: Sun, 19 Dec 2010 02:07:26 GMT
From: Tom Glinos <sonilg@utstat.toronto.edu>
To: freebsd-gnats-submit@FreeBSD.org
Subject: Modem Ring Signal not reliably detected
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>Number:         153289
>Category:       kern
>Synopsis:       Modem Ring Signal not reliably detected
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    gavin
>State:          feedback
>Quarter:        
>Keywords:       
>Date-Required:  
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Sun Dec 19 02:10:09 UTC 2010
>Closed-Date:    
>Last-Modified:  Sat Dec 25 21:52:43 UTC 2010
>Originator:     Tom Glinos
>Release:        8.1
>Organization:
U. of Toronto
>Environment:
FreeBSD atlas.jarnac.org 8.1-RELEASE FreeBSD 8.1-RELEASE #0: Mon Jul 19 02:55:53 UTC 2010     root@almeida.cse.buffalo.edu:/usr/obj/usr/src/sys/GENERIC  i386

>Description:

Modem Ring Signal not reliably detected.

>How-To-Repeat:
On the hardware side, create a switch that toggles DTR to RI. Also DTR to DSR.

On the software side, run a program to repeatedly scan the modem status register with a TIOCMGET ioctl

A toggle of DTR to DSR is always detected. A toggle of DTR to RI is less than half the time detected. Tested against two different serial hardware, similar behaviour.

The same code with same/similar hardware runs perfectly under LINUX.
>Fix:
Unknown at present. There are plenty of work arounds like changing the harware or OS but anyone still using a modem should be seeing this problem.

>Release-Note:
>Audit-Trail:
State-Changed-From-To: open->feedback 
State-Changed-By: gavin 
State-Changed-When: Sat Dec 25 21:50:20 UTC 2010 
State-Changed-Why:  
Hi, 

It's not immediately clear whether you are using real serial hardware (i.e. 
the uart(4) driver), puc(4), or if you are using a USB-serial adapter.  Can 
you please include details of the hardware in use? 

Thanks! 

Gavin 


Responsible-Changed-From-To: freebsd-bugs->gavin 
Responsible-Changed-By: gavin 
Responsible-Changed-When: Sat Dec 25 21:50:20 UTC 2010 
Responsible-Changed-Why:  
Track 

http://www.freebsd.org/cgi/query-pr.cgi?pr=153289 
>Unformatted:
