From d9c149d6ce1a94de578a4e323f6881fcb6b986ab Mon Sep 17 00:00:00 2001 From: Rui Wang Date: Sat, 10 Sep 2016 23:40:45 +0800 Subject: [PATCH] x86/ioapic: Ignore root bridges without a companion ACPI device Some PCI root bridges don't have a corresponding ACPI device. This can be the case on some old platforms. Don't call acpi_ioapic_add() on these bridges because they can't support ioapic hotplug. Reported-and-tested-by: Borislav Petkov Signed-off-by: Rui Wang Reviewed-by: Borislav Petkov Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: bhelgaas@google.com Cc: helgaas@kernel.org Cc: linux-acpi@vger.kernel.org Cc: linux-pci@vger.kernel.org Cc: rjw@rjwysocki.net Cc: tony.luck@intel.com Link: http://lkml.kernel.org/r/1473522046-31329-1-git-send-email-rui.y.wang@intel.com Signed-off-by: Ingo Molnar --- drivers/pci/setup-bus.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c index ec538d3d2bd5..f30ca75b5b6c 100644 --- a/drivers/pci/setup-bus.c +++ b/drivers/pci/setup-bus.c @@ -1855,7 +1855,10 @@ void __init pci_assign_unassigned_resources(void) list_for_each_entry(root_bus, &pci_root_buses, node) { pci_assign_unassigned_root_bus_resources(root_bus); - acpi_ioapic_add(ACPI_HANDLE(root_bus->bridge)); + + /* Make sure the root bridge has a companion ACPI device: */ + if (ACPI_HANDLE(root_bus->bridge)) + acpi_ioapic_add(ACPI_HANDLE(root_bus->bridge)); } }