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Date: Sat, 2 Aug 1997 23:27:12 -0700 (PDT)
From: Tom Samplonius <tom@sdf.com>
To: Charles Henrich <henrich@crh.cl.msu.edu>
cc: freebsd-hackers@freebsd.org
Subject: Re: tty-level buffer overflows
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On Sun, 3 Aug 1997, Charles Henrich wrote:

> I've searched the FreeBSD archives over and over, and all I find is dozens of
> complaints of this error (I too am seeing it:
> 
> sio0: 1081 more tty-level buffer overflows (total 3960)
> sio0: 526 more tty-level buffer overflows (total 4486)
> sio0: 532 more tty-level buffer overflows (total 5018)
> sio0: 2784 more tty-level buffer overflows (total 7802)
> sio0: 9439 more tty-level buffer overflows (total 17241)
> sio0: 677 more tty-level buffer overflows (total 17918)
> 
> But no resolutions.. Because of this I cannot use the serial ports on my
> FreeBSD box.. does anyone have any solutions? 

  Dozens of complaints?

  Generally the above is caused by a poor UART, and and an overloaded CPU.

  I've seen it with p2p links, when the link dies but the application (in
this case a stupid UDP app) keeps pumping data.  Since it has no place to
go, so the kernel throws it aways, and prints a warning.

  I've never seen that error in normal operation.  I see some overruns on
115200 bps ppp connection to 3COM ISDN TA.  But this was only a 486 that
is running a lot of stuff, and should be upgraded to a faster CPU.

> -Crh
> 
>        Charles Henrich     Michigan State University     henrich@msu.edu
> 
>                          http://pilot.msu.edu/~henrich
> 
> 

Tom