Date: Mon, 30 Apr 2001 09:03:25 -0700 (PDT) From: Rich Wales <richw@webcom.com> To: freebsd-current@freebsd.org Subject: Re: sio overflows Message-ID: <20010430154428.44707.richw@wyattearp.stanford.edu>
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Georg Funk wrote:
> I've recompiled my Kernel, and if I connect to the internet,
> my console is flooded by lots of sio overflows (on sio1),
> and my connection is very slow.
They're probably "silo" overflows; "silo" (a word which refers to a
tall, cylinder-shaped building for storing grain on a farm) is one name
for the input buffer of a serial I/O chip (another name is "FIFO", an
acronym for "First In, First Out").
Anyway . . . a few questions about your setup:
Are you using a serial cable that is set up to use hardware (CTS/RTS)
flow control? Is your modem configured to use hardware flow control?
If the answer to either of these questions is "no", then you aren't
using hardware flow control (even if you thought you were), and you
are =very= likely to lose data. Fix the cable and/or modem settings.
Is your serial port (sio1) identified as a "16550A" (the "A" suffix
is very important here) when FreeBSD starts up? If not, then you're
at risk of losing data at high communication rates (especially if your
computer is not extremely fast). Get a new serial card with 16550A
support.
Are you running the X Window System (XFree86) on the same computer
while you are connected to the Internet? If so, which version? Does
the serial I/O problem go away if you get out of X and work directly
with the plain-text console? There is a known problem with serial
I/O and version 4 of XFree86 -- though this problem doesn't seem to
exist with the XFree86 version (3.3.6) that is included by default in
FreeBSD. If you are using XFree86-4 and aren't willing to go back to
version 3.3.6, there may be a workaround for the serial I/O problem;
go to http://www.FreeBSD.org/cgi/query-pr.cgi and look up PR #26261
for more details.
Rich Wales richw@webcom.com http://www.webcom.com/richw/
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