1 files changed, 11 insertions, 1 deletions

diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
index d144168d4ef9..bf601d4df8cf 100644
--- a/drivers/acpi/pci_root.c
+++ b/drivers/acpi/pci_root.c
@@ -614,7 +614,17 @@ static int acpi_pci_root_add(struct acpi_device *device,
         if (hotadd) {
                 pcibios_resource_survey_bus(root->bus);
                 pci_assign_unassigned_root_bus_resources(root->bus);
-                acpi_ioapic_add(root);
+                /*
+                 * This is only called for the hotadd case. For the boot-time
+                 * case, we need to wait until after PCI initialization in
+                 * order to deal with IOAPICs mapped in on a PCI BAR.
+                 *
+                 * This is currently x86-specific, because acpi_ioapic_add()
+                 * is an empty function without CONFIG_ACPI_HOTPLUG_IOAPIC.
+                 * And CONFIG_ACPI_HOTPLUG_IOAPIC depends on CONFIG_X86_IO_APIC
+                 * (see drivers/acpi/Kconfig).
+                 */
+                acpi_ioapic_add(root->device->handle);
         }
 
         pci_lock_rescan_remove();