Re: [regression, bisected] fails to boot on Dell Optiplex 760 withVT-d enabled

From: David Woodhouse
Date: Mon Aug 17 2009 - 18:17:14 EST


On Mon, 2009-08-17 at 14:27 -0700, Faidon Liambotis wrote:
> I am experiencin a bug on an Dell Optiplex 760 with a configuration that
> has an Intel Core2 Q9550 CPU and with an up-to-date BIOS, version A03.
>
> When "VT for Direct I/O" is enabled in the BIOS, v2.6.30 boots and works
> perfectly, while v2.6.31-rc1..rc6 fail (both of them x86-64).
>
> More specifically, I get an endless loop of printing the following
> messages in
> the screen:
> DMAR: [DMA Read] Request device [ff:1f.7] fault addr
> fffffffffffff000
> DMAR: [fault reason 255] Unknown
> and the boot process doesn't move on from there.

Is it fixed by http://git.infradead.org/iommu-2.6.git/commit/0815565a ?

I strongly suspect you weren't actually using the IOMMU in your
'working' 2.6.30 kernel? Can you show a full log of that one booting?

--
David Woodhouse Open Source Technology Centre
David.Woodhouse@xxxxxxxxx Intel Corporation

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