Re: [PATCH v5] irq: add quirk for broken interrupt remapping on 55XX chipsets

2013-04-05 Thread Neil Horman
On Fri, Apr 05, 2013 at 03:25:54PM -0400, 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 
> CC: Prarit Bhargava 
> CC: Don Zickus 
> CC: Don Dutile 
> CC: Bjorn Helgaas 
> CC: Asit Mallick 
> CC: David Woodhouse 
> CC: linux-...@vger.kernel.org
> ---
> 
> Change notes:
> 
> v2)
> 
> * Moved the quirk to the x86 arch, since consensus seems to be that the 55XX
> chipset series is x86 only.  I decided however to keep the quirk as a regular
> quirk, not an early_quirk.  Early quirks have no way currently to determine if
> BIOS has properly disabled the feature in the iommu, at least not without
> significant hacking, and since its quite possible this will be a short lived
> quirk, should Don Z's workaround code prove successful (and it looks like it 
> may
> well), I don't think that necessecary.
> 
> * Removed the WARNING banner from the quirk, and added the HW_ERR token to the
> string, I opted to leave the newlines in place however, as I really couldnt
> find a way to keep the text on a single line is still legible from a code
> perspective.  I think theres enough language in there that using cscope on 
> just
> about any substring however will turn it up, and again, this may be a short
> lived quirk.
> 
> v3)
> 
> * Removed defines from pci_ids.h, and used direct id values as per request 
> from
> Bjorn.
> 
> v4)
> 
> * Converted pr_warn to WARN_TAINT(TAINT_FIRMWARE_WORKAROUND) as per David
> Woodhouse
> 
> v5)
> 
> * Moved check to an early quirk, and flagged the broken chip, so we could
> reasonably disable irq remapping during bootup.


Self NAK, sorry, I've got extra water in the quirks file left over from my move.

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Re: [PATCH v5] irq: add quirk for broken interrupt remapping on 55XX chipsets

2013-04-05 Thread Neil Horman
On Fri, Apr 05, 2013 at 03:25:54PM -0400, 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 nhor...@tuxdriver.com
 CC: Prarit Bhargava pra...@redhat.com
 CC: Don Zickus dzic...@redhat.com
 CC: Don Dutile ddut...@redhat.com
 CC: Bjorn Helgaas bhelg...@google.com
 CC: Asit Mallick asit.k.mall...@intel.com
 CC: David Woodhouse dw...@infradead.org
 CC: linux-...@vger.kernel.org
 ---
 
 Change notes:
 
 v2)
 
 * Moved the quirk to the x86 arch, since consensus seems to be that the 55XX
 chipset series is x86 only.  I decided however to keep the quirk as a regular
 quirk, not an early_quirk.  Early quirks have no way currently to determine if
 BIOS has properly disabled the feature in the iommu, at least not without
 significant hacking, and since its quite possible this will be a short lived
 quirk, should Don Z's workaround code prove successful (and it looks like it 
 may
 well), I don't think that necessecary.
 
 * Removed the WARNING banner from the quirk, and added the HW_ERR token to the
 string, I opted to leave the newlines in place however, as I really couldnt
 find a way to keep the text on a single line is still legible from a code
 perspective.  I think theres enough language in there that using cscope on 
 just
 about any substring however will turn it up, and again, this may be a short
 lived quirk.
 
 v3)
 
 * Removed defines from pci_ids.h, and used direct id values as per request 
 from
 Bjorn.
 
 v4)
 
 * Converted pr_warn to WARN_TAINT(TAINT_FIRMWARE_WORKAROUND) as per David
 Woodhouse
 
 v5)
 
 * Moved check to an early quirk, and flagged the broken chip, so we could
 reasonably disable irq remapping during bootup.


Self NAK, sorry, I've got extra water in the quirks file left over from my move.

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Please read the FAQ at  http://www.tux.org/lkml/