1 files changed, 9 insertions, 2 deletions

diff --git a/drivers/acpi/pci_link.c b/drivers/acpi/pci_link.c
index fcfdef7b4fdd..e52ad91ce2dc 100644
--- a/drivers/acpi/pci_link.c
+++ b/drivers/acpi/pci_link.c
@@ -531,7 +531,7 @@ int __init acpi_irq_penalty_init(void)
         return 0;
 }
 
-static int acpi_irq_balance;    /* 0: static, 1: balance */
+static int acpi_irq_balance = -1;       /* 0: static, 1: balance */
 
 static int acpi_pci_link_allocate(struct acpi_pci_link *link)
 {
@@ -950,10 +950,17 @@ device_initcall(irqrouter_init_sysfs);
 
 static int __init acpi_pci_link_init(void)
 {
-
         if (acpi_noirq)
                 return 0;
 
+        if (acpi_irq_balance == -1) {
+                /* no command line switch: enable balancing in IOAPIC mode */
+                if (acpi_irq_model == ACPI_IRQ_MODEL_IOAPIC)
+                        acpi_irq_balance = 1;
+                else
+                        acpi_irq_balance = 0;
+        }
+
         acpi_link.count = 0;
         INIT_LIST_HEAD(&acpi_link.entries);