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Date: Sat, 31 Mar 2001 19:05:08 -0800 (PST)
From: richw@webcom.com
To: freebsd-gnats-submit@FreeBSD.org
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Subject: i386/26261: silo overflow problem in sio driver
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>Number:         26261
>Category:       i386
>Synopsis:       silo overflow problem in sio driver
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Sat Mar 31 19:10:01 PST 2001
>Closed-Date:
>Last-Modified:
>Originator:     Rich Wales
>Release:        4.2-RELEASE
>Organization:
>Environment:
FreeBSD jekyll.richw.org 4.2-RELEASE FreeBSD 4.2-RELEASE #8: Sat Mar  3 21:17:31 PST 2001     richw@jekyll.richw.org:/big/4.2/usr/src/sys/compile/JEKYLL  i386
>Description:
I'm getting lots of "silo overflow" errors on an internal serial port
in my 800-MHz Athlon system.

I tried patching isa/sio.c to set a lower receive FIFO threshold, but
even with a threshold of FIFO_RX_MEDL, I still get silo overflows unless
I reduce the serial port speed to 19200 or slower.

The serial port works flawlessly if I run Win98 and Hyperterm -- so I
assume the problem is in FreeBSD and not in my hardware.
>How-To-Repeat:
Sustained high-speed serial input at 38400 or above.
>Fix:
No fix known.  Reducing port speed to 19200 or slower is a workaround,
but not a very satisfying one.
>Release-Note:
>Audit-Trail:
>Unformatted:

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