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:

quoted

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.

Regards,
-- 
Tomáš Janoušek, a.k.a. Liskni_si, http://work.lisk.in/