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Date: Wed, 24 Jul 2002 18:37:28 -0400
From: Pete Zaitcev <zaitcev@redhat.com>
Message-Id: <200207242237.g6OMbSO10262@devserv.devel.redhat.com>
To: Bill Davidsen <davidsen@tmr.com>
Cc: linux-kernel@vger.kernel.org
Subject: Re: Safety of IRQ during i/o
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>[...]
> I would think that this would be safe when using DMA, and likely to be
> safe for PIO and more recent chipsets, but I wouldn't want to actually
> tell anyone that.

A little story from OLS. I have a 486/75 laptop, which can only
do PIO. It always was losing characters evern on 9600 baud on its
serial port, and I thought it was simply broken for five years.
A guy who did a security talk showed me that doing hdparm -u
fixes the problem. Apparently, the lappy has a non-buffering UART.

So, it seems that hdparm -u is a very useful thing for obsotele
boxes. If you do DMA, you probably do not care.

-- Pete
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