Commit a0040c01 authored Sep 14, 2017 by Vitaly Kuznetsov Committed by Bjorn Helgaas Oct 05, 2017

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>

parent 9e66317d

drivers/pci/pci-acpi.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -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);

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