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    Subject[PATCH 4.14 110/159] PCI: Avoid bus reset if bridge itself is broken
    4.14-stable review patch.  If anyone has any objections, please let me know.


    From: David Daney <>

    [ Upstream commit 357027786f3523d26f42391aa4c075b8495e5d28 ]

    When checking to see if a PCI bus can safely be reset, we previously
    checked to see if any of the children had their PCI_DEV_FLAGS_NO_BUS_RESET
    flag set. Children marked with that flag are known not to behave well
    after a bus reset.

    Some PCIe root port bridges also do not behave well after a bus reset,
    sometimes causing the devices behind the bridge to become unusable.

    Add a check for PCI_DEV_FLAGS_NO_BUS_RESET being set in the bridge device
    to allow these bridges to be flagged, and prevent their secondary buses
    from being reset.

    Signed-off-by: David Daney <>
    [ fixed typo]
    Signed-off-by: Jan Glauber <>
    Signed-off-by: Bjorn Helgaas <>
    Reviewed-by: Alex Williamson <>

    Signed-off-by: Sasha Levin <>
    Signed-off-by: Greg Kroah-Hartman <>
    drivers/pci/pci.c | 4 ++++
    1 file changed, 4 insertions(+)

    --- a/drivers/pci/pci.c
    +++ b/drivers/pci/pci.c
    @@ -4356,6 +4356,10 @@ static bool pci_bus_resetable(struct pci
    struct pci_dev *dev;

    + if (bus->self && (bus->self->dev_flags & PCI_DEV_FLAGS_NO_BUS_RESET))
    + return false;
    list_for_each_entry(dev, &bus->devices, bus_list) {
    if (dev->dev_flags & PCI_DEV_FLAGS_NO_BUS_RESET ||
    (dev->subordinate && !pci_bus_resetable(dev->subordinate)))

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