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Date: Mon, 07 Feb 2005 03:58:08 -0500
From: Jeff Garzik <jgarzik@pobox.com>
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To: Tejun Heo <htejun@gmail.com>,
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CC: linux-ide@vger.kernel.org, linux-kernel@vger.kernel.org,
       Alan Cox <alan@lxorguk.ukuu.org.uk>, Tejun Heo <tj@home-tj.org>
Subject: Re: [rfc][patch] ide: fix unneeded LBA48 taskfile registers access
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FWIW, there are two limitations of libata in this area:

1) ISTR some PATA vendor-specific commands have a very specific set of 
input and output registers to use, and input/output sets of registers 
may differ from each other.

2) libata is lazy, and just reads registers in "groups":  the 
lbaH/M/L/nsect registers, the device register, etc.