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

[Neil Horman]

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@xxxxxxxxxxxxx>
> CC: Prarit Bhargava <prarit@xxxxxxxxxx>
> CC: Don Zickus <dzickus@xxxxxxxxxx>
> CC: Don Dutile <ddutile@xxxxxxxxxx>
> CC: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
> CC: Asit Mallick <asit.k.mallick@xxxxxxxxx>
> CC: linux-pci@xxxxxxxxxxxxxxx
> 
Ping, anyone want to Ack/Nack this?
Neil

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