From: Robert Hancock <hancockr@shaw.ca>
To: Linus Torvalds <torvalds@osdl.org>
Cc: linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: Memory barriers and spin_unlock safety
Date: Fri, 10 Mar 2006 19:19:51 -0600 [thread overview]
Message-ID: <441225B7.5010003@shaw.ca> (raw)
In-Reply-To: <5NY0h-7wa-1@gated-at.bofh.it>
Linus Torvalds wrote:
> Close, yes. HOWEVER, it's only really ordered wrt the "innermost" bus. I
> don't think PCI bridges are supposed to post PIO writes, but a x86 CPU
> basically won't stall for them forever. I _think_ they'll wait for it to
> hit that external bus, though.
PCI I/O writes are allowed to be posted by the host bus bridge (not
other bridges) according to the PCI 2.2 spec. Maybe no x86 platform
actually does this, but it's allowed, so technically a device would need
to do a read in order to ensure that I/O writes have arrived at the
device as well.
--
Robert Hancock Saskatoon, SK, Canada
To email, remove "nospam" from hancockr@nospamshaw.ca
Home Page: http://www.roberthancock.com/
next parent reply other threads:[~2006-03-11 4:02 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <5Ml19-2Ki-19@gated-at.bofh.it>
[not found] ` <5MlO0-3JU-13@gated-at.bofh.it>
[not found] ` <5MCF0-2TS-27@gated-at.bofh.it>
[not found] ` <5MITJ-2l4-15@gated-at.bofh.it>
[not found] ` <5NXxl-6WZ-9@gated-at.bofh.it>
[not found] ` <5NY0h-7wa-1@gated-at.bofh.it>
2006-03-11 1:19 ` Robert Hancock [this message]
2006-03-12 18:09 ` Memory barriers and spin_unlock safety Alan Cox
2006-03-03 16:03 David Howells
2006-03-03 16:45 ` David Howells
2006-03-03 17:03 ` Linus Torvalds
2006-03-03 20:17 ` David Howells
2006-03-03 21:34 ` Linus Torvalds
2006-03-03 21:51 ` Benjamin LaHaise
2006-03-03 22:21 ` Linus Torvalds
2006-03-03 22:36 ` Linus Torvalds
2006-03-07 17:36 ` David Howells
2006-03-07 17:40 ` Matthew Wilcox
2006-03-07 17:56 ` Jesse Barnes
2006-03-07 18:18 ` Alan Cox
2006-03-07 18:28 ` Linus Torvalds
2006-03-07 18:55 ` Alan Cox
2006-03-07 20:21 ` Linus Torvalds
2006-03-06 9:06 ` Helge Hafting
2006-03-03 20:02 ` Arjan van de Ven
2006-03-03 16:55 ` Linus Torvalds
2006-03-03 20:15 ` David Howells
2006-03-03 21:31 ` Linus Torvalds
2006-03-03 21:06 ` Benjamin Herrenschmidt
2006-03-03 21:18 ` Hollis Blanchard
2006-03-03 21:52 ` David S. Miller
2006-03-03 22:04 ` Linus Torvalds
2006-03-04 10:58 ` Paul Mackerras
2006-03-04 22:49 ` Benjamin Herrenschmidt
2006-03-04 10:58 ` Paul Mackerras
2006-03-04 17:28 ` Linus Torvalds
2006-03-08 3:20 ` Paul Mackerras
2006-03-08 3:54 ` Linus Torvalds
2006-03-08 13:12 ` Alan Cox
2006-03-08 15:30 ` Linus Torvalds
2006-03-05 2:04 ` Michael Buesch
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