From: Tejun Heo <htejun@gmail.com>
To: Robert Hancock <hancockr@shaw.ca>
Cc: linux-kernel <linux-kernel@vger.kernel.org>,
ide <linux-ide@vger.kernel.org>, Jeff Garzik <jeff@garzik.org>
Subject: Re: [PATCH] sata_nv: don't use legacy DMA in ADMA mode (v2)
Date: Sat, 24 Nov 2007 14:16:43 +0900 [thread overview]
Message-ID: <4747B3BB.4000708@gmail.com> (raw)
In-Reply-To: <47463580.8080909@shaw.ca>
Robert Hancock wrote:
> We need to run any DMA command with result taskfile requested in ADMA mode
> when the port is in ADMA mode, otherwise it may try to use the legacy DMA engine
> in ADMA mode which is not allowed. Enforce this with BUG_ON() since data
> corruption could potentially result if this happened. Also WARN_ON() if we try
> and send result taskfile commands while NCQ commands are still active, since the
> hardware doesn't allow this.
>
> Signed-off-by: Robert Hancock <hancockr@shaw.ca>
>
> @@ -1425,9 +1427,17 @@
> + /* We can't handle result taskfile with NCQ commands active, since
> + retrieving the taskfile switches us out of ADMA mode and would abort
> + existing commands. */
> + WARN_ON((qc->flags & ATA_QCFLAG_RESULT_TF) &&
> + (qc->ap->qc_allocated & ~(1 << qc->tag)));
I owe an apology here. ap->qc_allocated & ~(1 << qc->tag) test isn't
correct. Sorry. qc deferring happens after qc is allocated so the
condition can trigger (although it should be rare) even when nothing is
going wrong, so I guess it should be WARN_ON((qc->flags &
ATA_QCFLAG_RESULT_TF) && link->sactive).
Sorry. :-)
--
tejun
next prev parent reply other threads:[~2007-11-24 5:17 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-11-23 2:05 [PATCH] sata_nv: don't use legacy DMA in ADMA mode (v2) Robert Hancock
2007-11-24 5:16 ` Tejun Heo [this message]
2007-11-24 5:19 ` Tejun Heo
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=4747B3BB.4000708@gmail.com \
--to=htejun@gmail.com \
--cc=hancockr@shaw.ca \
--cc=jeff@garzik.org \
--cc=linux-ide@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).