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ACPI / PCI: Bail early in acpi_pci_add_bus() if there is no ACPI handle 

Hyper-V instances support PCI pass-through which is implemented through PV
pci-hyperv driver. When a device is passed through, a new root PCI bus is
created in the guest. The bus sits on top of VMBus and has no associated
information in ACPI. acpi_pci_add_bus() in this case proceeds all the way
to acpi_evaluate_dsm(), which reports

  ACPI: \: failed to evaluate _DSM (0x1001)

While acpi_pci_slot_enumerate() and acpiphp_enumerate_slots() are protected
against ACPI_HANDLE() being NULL and do nothing, acpi_evaluate_dsm() is not
and gives us the error. It seems the correct fix is to not do anything in
acpi_pci_add_bus() in such cases.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
hifive-unleashed-5.1
Vitaly Kuznetsov 2017-09-14 16:50:14 +02:00 committed by Bjorn Helgaas
parent 9e66317d3c
commit a0040c0145
1 changed files with 1 additions and 1 deletions
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2
drivers/pci/pci-acpi.c
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@ -624,7 +624,7 @@ void acpi_pci_add_bus(struct pci_bus *bus)
union acpi_object *obj;
struct pci_host_bridge *bridge;
if (acpi_pci_disabled || !bus->bridge)
if (acpi_pci_disabled || !bus->bridge || !ACPI_HANDLE(bus->bridge))
return;
acpi_pci_slot_enumerate(bus);