From: Matthew Wilcox <matthew@wil.cx>
To: Roland Dreier <rdreier@cisco.com>
Cc: Jeff Garzik <jeff@garzik.org>,
linux-pci@atrey.karlin.mff.cuni.cz, linux-ia64@vger.kernel.org,
linux-kernel@vger.kernel.org, openib-general@openib.org,
John Partridge <johnip@sgi.com>
Subject: Re: Ordering between PCI config space writes and MMIO reads?
Date: Tue, 24 Oct 2006 22:36:32 +0000 [thread overview]
Message-ID: <20061024223631.GT25210@parisc-linux.org> (raw)
In-Reply-To: <adar6wxbcwt.fsf@cisco.com>
On Tue, Oct 24, 2006 at 02:51:30PM -0700, Roland Dreier wrote:
> > I think the right way to fix this is to ensure mmio write ordering in
> > the pci_write_config_*() implementations. Like this.
>
> I'm happy to fix this in the PCI core and not force drivers to worry
> about this.
>
> John, can you confirm that this patch fixes the issue for you?
Hang on. I wasn't thinking clearly. mmiowb() only ensures the write
has got as far as the shub. There's no way to fix this in the pci core
-- any PCI-PCI bridge can reorder the two.
This is only really a problem for setup (when we program the BARs), so
it seems silly to enforce an ordering at any other time. Reluctantly, I
must disagree with Jeff -- drivers need to fix this.
next prev parent reply other threads:[~2006-10-24 22:36 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-10-24 19:13 Ordering between PCI config space writes and MMIO reads? Roland Dreier
2006-10-24 19:22 ` Jeff Garzik
2006-10-24 21:47 ` Matthew Wilcox
2006-10-24 21:51 ` Roland Dreier
2006-10-24 22:12 ` John Partridge
2006-10-24 22:36 ` Matthew Wilcox [this message]
2006-10-24 22:43 ` David Miller
2006-10-25 14:15 ` Roland Dreier
2006-10-31 19:02 ` Roland Dreier
2006-10-31 19:53 ` Michael S. Tsirkin
2006-10-31 19:53 ` Roland Dreier
2006-10-31 19:58 ` Matthew Wilcox
2006-10-31 20:28 ` Michael S. Tsirkin
2006-10-31 20:34 ` Richard B. Johnson
2006-10-31 20:47 ` Matthew Wilcox
2006-10-31 22:30 ` Roland Dreier
2006-11-01 16:27 ` John Partridge
2006-11-01 16:46 ` Matthew Wilcox
2006-11-01 17:08 ` John Partridge
2006-11-01 17:14 ` Matthew Wilcox
2006-11-01 23:04 ` David Miller
2006-11-02 1:08 ` John Partridge
2006-10-31 20:50 ` Michael S. Tsirkin
2006-10-24 22:59 ` [openib-general] " Jason Gunthorpe
2006-10-25 14:04 ` Roland Dreier
2006-10-24 23:09 ` Michael S. Tsirkin
2006-10-24 23:27 ` Jack Steiner
2006-10-25 14:05 ` Roland Dreier
2006-11-02 3:05 ` Jeremy Higdon
2006-10-24 21:01 ` [openib-general] " JWM
2006-10-24 21:24 ` Alan Cox
2006-10-24 21:29 ` Roland Dreier
2006-10-24 21:37 ` Jeff Garzik
2006-10-25 6:30 ` Grant Grundler
2006-10-25 14:11 ` Roland Dreier
2006-10-25 14:18 ` Matthew Wilcox
2006-10-25 17:15 ` [openib-general] " Jason Gunthorpe
2006-10-25 18:22 ` Michael S. Tsirkin
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=20061024223631.GT25210@parisc-linux.org \
--to=matthew@wil.cx \
--cc=jeff@garzik.org \
--cc=johnip@sgi.com \
--cc=linux-ia64@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-pci@atrey.karlin.mff.cuni.cz \
--cc=openib-general@openib.org \
--cc=rdreier@cisco.com \
/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