On Fri, Mar 01, 2013 at 10:20:35AM -0800, Yinghai Lu wrote: > 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 > I was under the impression that BIOS might have enabled irq remapping prior to the OS booting, at which point a reboot was requried anyway. Neil -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
