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

[Yinghai Lu]

On Fri, Mar 1, 2013 at 9:17 AM, Neil Horman <nhorman@xxxxxxxxxxxxx> 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
> ---
>  drivers/iommu/intel_irq_remapping.c | 20 ++++++++++++++++++++
>  include/linux/pci_ids.h             |  2 ++
>  2 files changed, 22 insertions(+)
>
> diff --git a/drivers/iommu/intel_irq_remapping.c b/drivers/iommu/intel_irq_remapping.c
> index f3b8f23..9bfb6c2 100644
> --- a/drivers/iommu/intel_irq_remapping.c
> +++ b/drivers/iommu/intel_irq_remapping.c
> @@ -1113,3 +1113,23 @@ struct irq_remap_ops intel_irq_remap_ops = {
>         .msi_setup_irq          = intel_msi_setup_irq,
>         .setup_hpet_msi         = intel_setup_hpet_msi,
>  };
> +
> +
> +static void intel_remapping_check(struct pci_dev *dev)
> +{
> +       u8 revision;
> +
> +       pci_read_config_byte(dev, PCI_REVISION_ID, &revision);
> +
> +       if ((revision == 0x13) && irq_remapping_enabled) {
> +               pr_warn("WARNING WARNING WARNING WARNING WARNING WARNING\n"
> +                       "This system BIOS has enabled interrupt remapping\n"
> +                       "on a chipset that contains an errata making that\n"
> +                       "feature unstable.  Please reboot with nointremap\n"
> +                       "added to the kernel command line and contact\n"
> +                       "your BIOS vendor for an update");
> +       }
> +}
> +DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_5520_IOHUB, intel_remapping_check);
> +DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_5500_IOHUB, intel_remapping_check);

only for x86 platform?
If so, you can check that in arch/x86/kernel/early-quirks.c::early_quirks()
and set one flag and later print warning and skip there if someone
need to enable intr-remap.
So users will not need to reboot the system...

Thanks

Yinghai

> +
> diff --git a/include/linux/pci_ids.h b/include/linux/pci_ids.h
> index 31717bd..54027a6 100644
> --- a/include/linux/pci_ids.h
> +++ b/include/linux/pci_ids.h
> @@ -2732,6 +2732,8 @@
>  #define PCI_DEVICE_ID_INTEL_LYNNFIELD_MC_CH2_RANK_REV2  0x2db2
>  #define PCI_DEVICE_ID_INTEL_LYNNFIELD_MC_CH2_TC_REV2    0x2db3
>  #define PCI_DEVICE_ID_INTEL_82855PM_HB 0x3340
> +#define PCI_DEVICE_ID_INTEL_5500_IOHUB 0x3403
> +#define PCI_DEVICE_ID_INTEL_5520_IOHUB 0x3406
>  #define PCI_DEVICE_ID_INTEL_IOAT_TBG4  0x3429
>  #define PCI_DEVICE_ID_INTEL_IOAT_TBG5  0x342a
>  #define PCI_DEVICE_ID_INTEL_IOAT_TBG6  0x342b
> --
> 1.7.11.7
>
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