Subject: Re: iwlagn: memory corruption with WPA enterprise
From: wwguy <wey-yi.w.guy@intel.com>
To: =?UTF-8?Q?Tom=C3=A1=C5=A1_Janou=C5=A1ek?= <tomi@nomi.cz>
Cc: Stanislaw Gruszka <sgruszka@redhat.com>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"linux-wireless@vger.kernel.org" <linux-wireless@vger.kernel.org>
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Date: Sat, 19 Nov 2011 18:13:53 -0800
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On Sat, 2011-11-19 at 10:11 -0800, Tomáš Janoušek wrote:
> Hello,
> 
> On Mon, Nov 14, 2011 at 03:07:15PM +0100, Stanislaw Gruszka wrote:
> > On Fri, Nov 11, 2011 at 04:01:05PM +0100, Tomáš Janoušek wrote:
> > > Could you please elaborate on that thing with enabling IOMMU? The only thing I
> > > know about IOMMU is that it is somehow related to VT-d (passing whole PCI
> > > devices to virtual guests), and that I have to pass intel_iommu=off to kernel
> > > command line, otherwise the machine doesn't even boot. Is that a problem?
> > Yes. That mean iommu software or hardware is broken on your system.
> >
> > I have no other ideas how to track this down. I think now, this is
> > a firwmare issue. BTW, you suspected that from very beginning :-)
> > This could be also a driver issue, but AFAICT programing DMA do not
> > differ on 6205 from other devices, so bug in firmware is much more
> > probable reason of corruption.
> 
> I have some news. I got IOMMU to work, because I identified the problem [1]
> and disabled firewire-ohci for the time being completely, but I'm not sure
> what do I need to do to make it catch the problem. I assumed that all I need
> is to intel_iommu=on and then all devices do DMA stuff in isolation, but I can
> still reproduce the issue without the smallest hint of an error in dmesg. Does
> it tell us anything, or shall I enable some more debugging stuff?
> 
> [1] http://thread.gmane.org/gmane.linux.kernel.pci/8765/focus=1217800
> 
> Anyway, I didn't get to trying 2.6.38/39 yet, but I will do that soon. It is
> also safe to say now that x86_64 is completely unaffected, as I was running
> various 64bit kernels the whole week without a single failure.
> 


hmm, I don't have any IOMMU supported system, I guess it is the time to
get one :-)

Wey