Re: DMAR:[fault reason 02] Present bit in context entry is clear (firewire-ohci)

Re: DMAR:[fault reason 02] Present bit in context entry is clear (firewire-ohci)

[Tomáš Janoušek]

Hello guys,

On Sat, May 22, 2010 at 12:09:05PM -0700, Jesse Barnes wrote:
> On Sat, 22 May 2010 19:40:43 +0100
> David Woodhouse <dwmw2@infradead.org> wrote:
> > [...]
> > Yeah, the DMAR looks at the source-id in the PCIe transactions, and it
> > sounds like those are all 04:00.0. But we've probably set up the DMAR to
> > allow the transactions from 04:00.4, and then it naturally faults when a
> > "different" device actually ends up doing the transaction.
> > 
> > If you make the pci_find_upstream_pcie_bridge() function do the
> > appropriate thing for this device, does it then work as expected?
> > 
> > Whether that's a _sane_ thing to do or not is possibly more of a Jesse
> > question...
> 
> Well, if cardbus bridges tend to behave this way in general it would
> make sense to simply use the cardbus bride id everywhere, rather than
> the specific functions of the device.  Cc'ing Dominik.

Any news on this one? It is still an issue with current kernel on current
hardware (like my ThinkPad T420). :-(

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

Re: DMAR:[fault reason 02] Present bit in context entry is clear (firewire-ohci)

[Clemens Ladisch]

Tomáš Janoušek wrote:
> On Sat, May 22, 2010 at 12:09:05PM -0700, Jesse Barnes wrote:
>> On Sat, 22 May 2010 19:40:43 +0100
>> David Woodhouse <dwmw2@infradead.org> wrote:
>>> [...]
>>> Yeah, the DMAR looks at the source-id in the PCIe transactions, and it
>>> sounds like those are all 04:00.0. But we've probably set up the DMAR to
>>> allow the transactions from 04:00.4, and then it naturally faults when a
>>> "different" device actually ends up doing the transaction.
>>>
>>> If you make the pci_find_upstream_pcie_bridge() function do the
>>> appropriate thing for this device, does it then work as expected?
>>>
>>> Whether that's a _sane_ thing to do or not is possibly more of a Jesse
>>> question...
>>
>> Well, if cardbus bridges tend to behave this way in general it would
>> make sense to simply use the cardbus bride id everywhere, rather than
>> the specific functions of the device.  Cc'ing Dominik.
>
> Any news on this one?

Apparently not.

Try the patch in <https://bugzilla.redhat.com/show_bug.cgi?id=605888>
that is intended to work around the bug in your Ricoh chip.  Alternatively,
disable VT-d or FireWire in the BIOS, or add the kernel parameter
"intel_iommu=off".


Regards,
Clemens

Re: DMAR:[fault reason 02] Present bit in context entry is clear (firewire-ohci)

[Tomáš Janoušek]

Hi,

On Wed, Nov 30, 2011 at 05:16:54PM +0100, Clemens Ladisch wrote:
> Try the patch in <https://bugzilla.redhat.com/show_bug.cgi?id=605888>
> that is intended to work around the bug in your Ricoh chip.  Alternatively,
> disable VT-d or FireWire in the BIOS, or add the kernel parameter
> "intel_iommu=off".

Yeah, I guess that would work, I was just concerned with a fix not being in
the mainline. Surely we don't expect every ThinkPad user who wants to use
firewire and VT-d to apply the patch himself (the Fedora fix was to forcefully
disable IOMMU in presence of that Ricoh device). :-)

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