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Date: Thu, 2 Aug 2007 17:57:11 +0100
From: Alan Cox <alan@lxorguk.ukuu.org.uk>
To: Robert Hancock <hancockr@shaw.ca>
Cc: Mark Lord <lkml@rtr.ca>, "Maciej W. Rozycki" <macro@linux-mips.org>,
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       Lee Howard <faxguy@howardsilvan.com>, linux-serial@vger.kernel.org,
       tytso@mit.edu, linux-kernel@vger.kernel.org
Subject: Re: serial flow control appears broken
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> I think that PIO transfers only have to be done with interrupts disabled 
> on really old, evil controllers (without unmask set). I don't think 
> libata ever disables interrupts during transfers(?)

Currently libata PIO is mostly done in the IRQ path. Albert Lee was doing
some work on that but its actually very hard to fix without doing polled
PIO.