From: Alan Cox <alan@lxorguk.ukuu.org.uk>
To: Jeff Garzik <jgarzik@pobox.com>
Cc: Albert Lee <albertcc@tw.ibm.com>,
doug_maxey@us.ibm.com,
"linux-ide@vger.kernel.org" <linux-ide@vger.kernel.org>,
Bartlomiej Zolnierkiewicz <B.Zolnierkiewicz@elka.pw.edu.pl>,
Tejun Heo <htejun@gmail.com>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>
Subject: Re: Organized summary of the pacthes
Date: Tue, 28 Jun 2005 19:00:12 +0100 [thread overview]
Message-ID: <1119981611.32381.32.camel@localhost.localdomain> (raw)
In-Reply-To: <42C16AFC.7010908@pobox.com>
On Maw, 2005-06-28 at 16:21, Jeff Garzik wrote:
> These two patches make me REALLY nervous. This overrun business needs
> to be handled in a different way.
>
> For DMA, we will want to copy 0-3 odd bytes into a 4-byte buffer, and
> then make that 4-byte buffer than final DMA segment.
You may need 16 or 32 byte alignment for some hardware on the host side.
> However, I am pondering scrapping all the polling code, since on SATA,
> interrupt-driven mode is much more desirable.
You need both interrupt and polled command issue. ACPI needs to be able
to issue taskfiles to the IDE drive fairly early during resume. Right
now this isn't done at all. If polled is there it might also prove a
useful way to reissue a command when you think the IRQ routing is hosed
8)
There is a really nasty case here that the old IDE layer totally screwed
up: You may need to sequence speed changes into error recovery (BAD CRC)
which is coming from a timeout and irq context. In the sata layer at
least its from an eh thread.
Alan
next prev parent reply other threads:[~2005-06-28 18:03 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <42C12A10.8030308@tw.ibm.com>
2005-06-28 15:21 ` Organized summary of the pacthes Jeff Garzik
2005-06-28 18:00 ` Alan Cox [this message]
2005-07-10 0:54 ` Doug Maxey
2005-07-10 3:44 ` Jeff Garzik
2005-06-30 8:43 ` Albert Lee
2005-06-30 12:45 ` Al Boldi
2005-07-02 5:24 ` Tejun Heo
2005-06-30 17:10 ` Olaf Hering
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