From: Jesse Barnes <jbarnes@engr.sgi.com>
To: James Bottomley <James.Bottomley@steeleye.com>
Cc: Matthew Wilcox <willy@debian.org>,
Grant Grundler <grundler@parisc-linux.org>,
Andrew Vasquez <andrew.vasquez@qlogic.com>,
pj@sgi.com, SCSI Mailing List <linux-scsi@vger.kernel.org>,
mdr@cthulhu.engr.sgi.com, jeremy@cthulhu.engr.sgi.com,
djh@cthulhu.engr.sgi.com, Andrew Morton <akpm@osdl.org>
Subject: Re: SCSI QLA not working on latest *-mm SN2
Date: Tue, 21 Sep 2004 12:18:00 -0400 [thread overview]
Message-ID: <200409211218.00809.jbarnes@engr.sgi.com> (raw)
In-Reply-To: <1095783077.2467.145.camel@mulgrave>
On Tuesday, September 21, 2004 12:11 pm, James Bottomley wrote:
> On Tue, 2004-09-21 at 12:05, Jesse Barnes wrote:
> > Reading from the closest bridge won't be enough? If not, then dealing
> > with posting in a nice way is simply impossible for some devices. We'd
> > be stuck with udelay().
>
> That's correct. The posted write is held somewhere in one of the
> bridges, but the PCI ordering rules only require it to be ordered with
> other MMIO reads to the *device*; so you only guarantee that the posted
> write is flushed by doing a device read....obviously, there exist
> bridges with looser ideas than this, but we need to follow the PCI
> specs.
>
> udelay() isn't a viable solution because the PCI specs have no upper
> bound on the length of time a write may remain posted.
Well then. Sounds like we're hosed for the qla2xxx case at least. I think we
still need pioflush for the case of writes from different CPUs (described in
the document). Using it *should* make the window pretty small for qla2xxx
type problems too, but we have no guarantee.
Jesse
next prev parent reply other threads:[~2004-09-21 16:18 UTC|newest]
Thread overview: 96+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <B179AE41C1147041AA1121F44614F0B060EF48@AVEXCH02.qlogic.org>
[not found] ` <20040916121235.5e4f9c32.pj@sgi.com>
[not found] ` <1095362263.16326.12.camel@praka>
2004-09-16 19:56 ` SCSI QLA not working on latest *-mm SN2 Paul Jackson
2004-09-16 20:05 ` Jesse Barnes
2004-09-16 20:56 ` Andrew Vasquez
2004-09-16 21:09 ` Jesse Barnes
2004-09-16 21:40 ` Andrew Vasquez
2004-09-16 22:25 ` Andrew Morton
2004-09-16 22:29 ` Jesse Barnes
2004-09-17 17:21 ` Jesse Barnes
2004-09-18 6:10 ` Grant Grundler
2004-09-18 17:57 ` Documentation/io_ordering.txt is wrong Matthew Wilcox
2004-09-20 23:39 ` Jesse Barnes
2004-09-21 0:38 ` Jesse Barnes
2004-09-20 22:40 ` SCSI QLA not working on latest *-mm SN2 Jesse Barnes
2004-09-20 23:27 ` Grant Grundler
2004-09-21 0:09 ` Jesse Barnes
2004-09-21 5:46 ` Grant Grundler
2004-09-21 6:45 ` Jeremy Higdon
2004-09-21 13:29 ` Jesse Barnes
2004-09-21 13:25 ` Jesse Barnes
2004-09-21 15:13 ` Jesse Barnes
2004-09-21 15:41 ` James Bottomley
2004-09-21 15:58 ` Jesse Barnes
2004-09-21 16:01 ` Matthew Wilcox
2004-09-21 16:05 ` Jesse Barnes
2004-09-21 16:11 ` James Bottomley
2004-09-21 16:18 ` Jesse Barnes [this message]
2004-09-21 16:24 ` James Bottomley
2004-09-21 17:03 ` Jesse Barnes
2004-09-21 17:15 ` Matthew Wilcox
2004-09-21 17:24 ` Jesse Barnes
2004-09-21 17:20 ` James Bottomley
2004-09-21 17:46 ` Jesse Barnes
2004-09-21 17:56 ` James Bottomley
2004-09-21 18:09 ` Jesse Barnes
2004-09-21 19:06 ` Grant Grundler
2004-09-21 19:40 ` Jesse Barnes
2004-09-21 22:44 ` Grant Grundler
2004-09-21 21:03 ` Jeremy Higdon
2004-09-21 21:11 ` Matthew Wilcox
2004-09-21 21:43 ` Jeremy Higdon
2004-09-21 22:33 ` Jesse Barnes
2004-09-22 0:02 ` Matthew Wilcox
2004-09-22 1:16 ` Jeremy Higdon
2004-09-22 1:44 ` Grant Grundler
2004-09-22 2:58 ` Jeremy Higdon
2004-09-22 14:32 ` I/O write ordering Matthew Wilcox
2004-09-22 14:40 ` Benjamin Herrenschmidt
2004-09-22 14:50 ` Jesse Barnes
2004-09-22 14:47 ` James Bottomley
2004-09-22 14:51 ` Benjamin Herrenschmidt
2004-09-22 15:11 ` James Bottomley
2004-09-22 15:11 ` Benjamin Herrenschmidt
2004-09-22 15:22 ` James Bottomley
2004-09-22 15:28 ` Benjamin Herrenschmidt
2004-09-22 15:43 ` James Bottomley
2004-09-23 0:19 ` Benjamin Herrenschmidt
2004-09-23 1:58 ` Matthew Wilcox
2004-09-23 3:01 ` James Bottomley
2004-09-23 3:40 ` Benjamin Herrenschmidt
2004-09-23 4:26 ` Grant Grundler
2004-09-21 23:03 ` SCSI QLA not working on latest *-mm SN2 Guennadi Liakhovetski
2004-09-16 23:14 ` Jeremy Higdon
2004-09-16 20:11 ` Andrew Morton
2004-09-21 21:22 Andrew Vasquez
2004-09-21 21:44 ` Jeremy Higdon
2004-09-21 22:37 ` Jesse Barnes
2004-09-21 22:49 ` Jeremy Higdon
-- strict thread matches above, loose matches on Subject: below --
2004-09-21 20:50 Andrew Vasquez
2004-09-21 21:06 ` Jeremy Higdon
2004-09-21 22:36 ` Jesse Barnes
2004-09-21 22:39 ` Jeremy Higdon
2004-09-21 22:43 ` Jesse Barnes
2004-09-21 22:54 ` Jeremy Higdon
2004-09-21 23:17 ` Jesse Barnes
2004-09-22 21:33 ` Jesse Barnes
2004-09-21 17:33 Andrew Vasquez
2004-09-21 17:52 ` Jesse Barnes
2004-09-21 18:04 ` Matthew Wilcox
2004-09-21 18:59 ` Matthew Wilcox
2004-09-21 19:10 ` Jesse Barnes
2004-09-21 15:58 Andrew Vasquez
2004-09-21 16:07 ` Jesse Barnes
2004-09-21 16:25 ` Matthew Wilcox
2004-09-21 16:33 ` James Bottomley
2004-09-21 20:39 ` Jeremy Higdon
2004-09-21 20:43 ` Jeremy Higdon
2004-09-17 22:55 Andrew Vasquez
2004-09-17 23:10 ` Jesse Barnes
2004-09-17 23:55 ` James Bottomley
2004-09-18 1:15 ` Andrew Vasquez
2004-09-18 1:25 ` Matthew Wilcox
2004-09-18 1:24 ` Andrew Vasquez
2004-09-18 2:36 ` Jeremy Higdon
2004-09-18 19:12 ` James Bottomley
2004-09-15 22:51 Paul Jackson
2004-09-15 23:13 ` Andrew Morton
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