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    Subject[PATCH x86-64] Calgary - Fix mis-handled PCI topology
    Andrew, can you please push this Calgary bug-fix to 2.6.23 in your
    next merge? it fixes a showstopper bug in the recently merged CalIOC2
    support that hits machines with multiple levels of PCI-to-PCI bridges.

    Thanks,
    Muli
    ---
    From: Murillo Fernandes Bernardes <bernarde@br.ibm.com>
    Subject: x86-64: Calgary - Fix mis-handled PCI topology

    Current code assumed that devices were directly connected to a Calgary
    bridge, as it tried to get the iommu table directly from the parent bus
    controller.

    When we have another bridge between the Calgary/CalIOC2 bridge and the
    device we should look upwards until we get to the top (Calgary/CalIOC2
    bridge), where the iommu table resides.

    Signed-off-by: Murillo Fernandes Bernardes <mfb@br.ibm.com>
    Signed-off-by: Muli Ben-Yehuda <muli@il.ibm.com>

    --
    diff -ruN linux-2.6.23-rc1.orig/arch/x86_64/kernel/pci-calgary.c linux-2.6.23-rc1/arch/x86_64/kernel/pci-calgary.c
    --- linux-2.6.23-rc1.orig/arch/x86_64/kernel/pci-calgary.c 2007-08-01 15:37:04.000000000 -0300
    +++ linux-2.6.23-rc1/arch/x86_64/kernel/pci-calgary.c 2007-08-01 15:48:55.000000000 -0300
    @@ -367,16 +367,15 @@

    pdev = to_pci_dev(dev);

    - /* is the device behind a bridge? */
    - if (unlikely(pdev->bus->parent))
    - pbus = pdev->bus->parent;
    - else
    - pbus = pdev->bus;
    + pbus = pdev->bus;
    +
    + /* is the device behind a bridge? Look for the root bus */
    + while (pbus->parent)
    + pbus = pbus->parent;

    tbl = pci_iommu(pbus);

    - BUG_ON(pdev->bus->parent &&
    - (tbl->it_busno != pdev->bus->parent->number));
    + BUG_ON(tbl && (tbl->it_busno != pbus->number));

    return tbl;
    }




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