Re: [PATCH v2] irq: add quirk for broken interrupt remapping on 55XX chipsets

[Myron Stowe <myron.stowe@gmail.com>]

On Sat, Mar 9, 2013 at 1:49 PM, Neil Horman <nhorman@tuxdriver.com> wrote:
> On Mon, Mar 04, 2013 at 02:04:19PM -0500, Neil Horman wrote:
>> A few years back intel published a spec update:
>> http://www.intel.com/content/dam/doc/specification-update/5520-and-5500-chipset-ioh-specification-update.pdf
>>
>> For the 5520 and 5500 chipsets which contained an errata (specificially errata
>> 53), which noted that these chipsets can't properly do interrupt remapping, and
>> as a result the recommend that interrupt remapping be disabled in bios.  While
>> many vendors have a bios update to do exactly that, not all do, and of course
>> not all users update their bios to a level that corrects the problem.  As a
>> result, occasionally interrupts can arrive at a cpu even after affinity for that
>> interrupt has be moved, leading to lost or spurrious interrupts (usually
>> characterized by the message:
>> kernel: do_IRQ: 7.71 No irq handler for vector (irq -1)
>>
>> There have been several incidents recently of people seeing this error, and
>> investigation has shown that they have system for which their BIOS level is such
>> that this feature was not properly turned off.  As such, it would be good to
>> give them a reminder that their systems are vulnurable to this problem.
>>
>> Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
>> CC: Prarit Bhargava <prarit@redhat.com>
>> CC: Don Zickus <dzickus@redhat.com>
>> CC: Don Dutile <ddutile@redhat.com>
>> CC: Bjorn Helgaas <bhelgaas@google.com>
>> CC: Asit Mallick <asit.k.mallick@intel.com>
>> CC: linux-pci@vger.kernel.org
>>
> Ping, anyone want to Ack/Nack this?

Don's comment earlier seems to imply that this is a short term fix and
that a more long term fix may be coming soon.  If that is the case
wouldn't we want to wait for the long term fix and just pull that in?

Myron

> Neil
>
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