From: Roland Dreier <rdreier@cisco.com>
To: David Miller <davem@davemloft.net>
Cc: matthew@wil.cx, jeff@garzik.org,
linux-pci@atrey.karlin.mff.cuni.cz, linux-ia64@vger.kernel.org,
linux-kernel@vger.kernel.org, openib-general@openib.org,
johnip@sgi.com
Subject: Re: Ordering between PCI config space writes and MMIO reads?
Date: Wed, 25 Oct 2006 07:15:16 -0700 [thread overview]
Message-ID: <aday7r4a3d7.fsf@cisco.com> (raw)
In-Reply-To: <20061024.154347.77057163.davem@davemloft.net> (David Miller's message of "Tue, 24 Oct 2006 15:43:47 -0700 (PDT)")
> One thing is that we definitely don't want to fix this by,
> for example, reading back the PCI_COMMAND register or something
> like that. That causes two problems:
>
> 1) Some PCI config writes shut the device down and make it
> no respond to some kinds of PCI config transactions.
> One example is putting the device into D3 or similar
> power state, another is performing a device reset.
Hmm... it seems there is no other guaranteed way to make sure a config
write has really completed except doing a config read. And only the
driver knows what the config access it's doing means. So the
conclusion we seem to be forced into is that drivers need to include
these reads in the cases where they are needed.
- R.
next prev parent reply other threads:[~2006-10-25 14:15 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
2006-10-24 22:43 ` David Miller
2006-10-25 14:15 ` Roland Dreier [this message]
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=aday7r4a3d7.fsf@cisco.com \
--to=rdreier@cisco.com \
--cc=davem@davemloft.net \
--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=matthew@wil.cx \
--cc=openib-general@openib.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