Re: Linux 2.6.30-rc8 [also: VIA Support]

Harald Welte
2009-06-05T07:39:33Z

On Thu, Jun 04, 2009 at 10:16:35PM +0200, Andi Kleen wrote:
> 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)

Yes, sorry for not mentioning that. I was implicitly thinking of "not using an
appropriate locking method"

--
- Harald Welte <HaraldWelte@viatech.com> http://linux.via.com.tw/
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VIA Free and Open Source Software Liaison