Date: Fri, 15 Dec 1995 18:28:30 -0500
Message-Id: <199512152328.SAA14493@etinc.com>
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To: Bruce Evans <bde@zeta.org.au>
From: dennis@etinc.com (dennis)
Subject: Re: sio overruns on 2.0.5R
Cc: hackers@freebsd.org
Sender: owner-hackers@freebsd.org
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>>> After I switched to a Asus P55TP4XE 90Mc I see things like
>>> 
>>> sio0: 5 more silo overflows (total 7)
>>> 
>>> The Asus supposedly has 16550A UARTs, of which I use one. 
>>> 
>>> On my previous MB, a 25Mc 486DX
>>> I used an AST/4 with 16550A chips without a single silo overflow.
>>> I also have the impression the UUCP datarate is now slower than
>>> before.
>>> 
>>> This is a 14K4 modem BTW, on a 57600 baud line.
>
>>I hate to sound like a broken record, but are you *sure* you're using
>>flow-control?  Can you use stty on the connected end to make sure?
>
>Er, flow control has no effect on silo overflows.
>
>Perhaps the problem is a downgrade to a bus-hogging DMA controller.
>

Ah...bus mastering controllers! So unpredictable.

Does anyone know how these on-board IDE/IO asics are bussed to the system?
If they're bridged they could have secondary interrupts or something.....

I would  disable the on-board uart and try  the same AST board you used before
successfully just to see if it works.. Many of those IO asics emulate 16550s
but they're
not as good.

Dennis
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