To: Harald Welte <HaraldWelte@viatech.com>
Cc: "Michael S. Zick" <lkml@morethan.org>,
       Linus Torvalds <torvalds@linux-foundation.org>,
       Duane Griffin <duaneg@dghda.com>,
       Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: Linux 2.6.30-rc8 [also: VIA Support]
From: Andi Kleen <andi@firstfloor.org>
References: <alpine.LFD.2.01.0906022055030.4880@localhost.localdomain>
	<e9e943910906040900j6f334f29l42a9f5a57e9a1c8f@mail.gmail.com>
	<alpine.LFD.2.01.0906040910280.4880@localhost.localdomain>
	<200906041121.30845.lkml@morethan.org>
	<20090604174059.GB9823@prithivi.gnumonks.org>
Date: Thu, 04 Jun 2009 22:16:35 +0200
In-Reply-To: <20090604174059.GB9823@prithivi.gnumonks.org> (Harald Welte's message of "Thu, 4 Jun 2009 19:40:59 +0200")
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Harald Welte <HaraldWelte@viatech.com> writes:
>
> why would it matter on UP? as indicated, I'm not the expert here, but I thought
> memory ordering issues only arise in SMP systems [or possibly with regard to
> DMA, but as we already explored much earlier in this thread, drivers that access
> DMA buffers whil the hardware owns them are buggy and need to be fixed]

Sorry we didn't establish that. Accessing data structures that are
also accessed by DMA hardware is pretty common in fact and memory
ordering issues also come up regularly (e.g. all the infamous PCI
posting bugs)

What we established is that the drivers don't use LOCK for it
(or at least we think that's very unlikely)

-Andi

-- 
ak@linux.intel.com -- Speaking for myself only.
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