From: David Gibson <david@gibson.dropbear.id.au>
To: Nathan Lynch <ntl@pobox.com>
Cc: linuxppc-dev@ozlabs.org, Paul Mackerras <paulus@samba.org>
Subject: Re: [RFC/PATCH] remove gratuitous reads from maple pci config space methods
Date: Thu, 9 Aug 2007 14:18:03 +1000 [thread overview]
Message-ID: <20070809041803.GG8261@localhost.localdomain> (raw)
In-Reply-To: <20070809041632.GA13921@localdomain>
On Wed, Aug 08, 2007 at 11:16:32PM -0500, Nathan Lynch wrote:
> David Gibson wrote:
> > On Wed, Aug 08, 2007 at 07:50:44PM -0500, Nathan Lynch wrote:
> > > The maple pci configuration space write methods read the written
> > > location immediately after the write is performed, presumably in order
> > > to flush the write. However, configuration space writes are not
> > > allowed to be posted, making these reads gratuitous.
> >
> > It might be worth checking that there isn't a particular reason for
> > these. Just because posting writes are forbidden doesn't mean a
> > particular bridge won't screw it up...
>
> Well, I had already checked with Ben, who wrote the code, and my
> understanding is that the reads are intended to work around some
> misbehaving Apple bridges, but that a sync after the write (implied by
> releasing pci_lock in the generic pci code) should suffice for
> those.
Ah, ok then.
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
next prev parent reply other threads:[~2007-08-09 4:18 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-08-09 0:50 [RFC/PATCH] remove gratuitous reads from maple pci config space methods Nathan Lynch
2007-08-09 0:55 ` Benjamin Herrenschmidt
2007-08-09 1:04 ` Nathan Lynch
2007-08-09 1:14 ` Benjamin Herrenschmidt
2007-08-09 20:03 ` Olof Johansson
2007-08-09 3:05 ` David Gibson
2007-08-09 4:16 ` Nathan Lynch
2007-08-09 4:18 ` David Gibson [this message]
2007-08-09 10:40 ` Segher Boessenkool
2007-08-09 21:24 ` Nathan Lynch
2007-08-10 17:58 ` Segher Boessenkool
2007-08-11 23:41 ` Benjamin Herrenschmidt
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=20070809041803.GG8261@localhost.localdomain \
--to=david@gibson.dropbear.id.au \
--cc=linuxppc-dev@ozlabs.org \
--cc=ntl@pobox.com \
--cc=paulus@samba.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).