Date: Sun, 4 Nov 2007 23:42:05 +0000
From: Alan Cox <alan@lxorguk.ukuu.org.uk>
To: albertl@mail.com
Cc: albertcc@tw.ibm.com, Tejun Heo <htejun@gmail.com>,
       Daniel Drake <dsd@gentoo.org>, Jeff Garzik <jeff@garzik.org>,
       Jens Axboe <jens.axboe@oracle.com>,
       linux list <linux-kernel@vger.kernel.org>, linux-ide@vger.kernel.org
Subject: Re: "Fix ATAPI transfer lengths" causes CD writing regression
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> Maybe we could set a limit here. If the ATAPI device keeps DRQ=1 and
> exceeds the limit, we consider it as HSM violation and have EH handle it.

On a DMA transfer its basically out of our control (and a PIO drain will
lock some controllers solid until power cycle), but on PIO we know we
never set a chunk size over 64K, so if we exceed 64K its time to apply a
larger hammer
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