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Date: Sat, 27 Sep 2008 02:30:29 +0300
From: "Tomas Winkler" <tomasw@gmail.com>
To: "Johannes Berg" <johannes@sipsolutions.net>
Subject: Re: bad DMAR interaction with iwlagn and SATA
Cc: "Muli Ben-Yehuda" <muli@il.ibm.com>,
	"Jeff Garzik" <jeff@garzik.org>,
	"Andres Freund" <andres@anarazel.de>, linux-kernel@vger.kernel.org,
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On Fri, Sep 26, 2008 at 6:12 PM, Johannes Berg
<johannes@sipsolutions.net> wrote:
> On Fri, 2008-09-26 at 17:47 +0300, Muli Ben-Yehuda wrote:
>
>> The way to debug this is to figure out why device 00:1f.2 is trying to
>> read from DMA address fffbf000 and does not have permission to do
>> so. This could be indicative of a driver bug where it is programming
>> the device to read from some buffer that has not been allocated
>> through the DMA API and thus does not have a valid IOMMU mapping, or a
>> hardware quirk where the device tries to read from memory without host
>> involvement. The former is much more likely.
>
> The same is probably true for the iwlagn case which was
>
>> [ 4184.617392] DMAR:[DMA Read] Request device [03:00.0] fault addr fa946000
>> [ 4184.617393] DMAR:[fault reason 06] PTE Read access is not set
>> [ 4184.644081] iwlagn: Microcode HW error detected.  Restarting.
>
> and indeed matches experience from myself and Marcel that DMA bugs seem
> to lurk.

Meanwhile it all reported bugs in this case points to 64 bit
installations, I'll give it more testing
Thnaks.
Tomas