3 files changed, 9 insertions, 4 deletions

diff --git a/arch/x86/include/asm/acpi.h b/arch/x86/include/asm/acpi.h
index 8d676d8ecde9..9830681446ad 100644
--- a/arch/x86/include/asm/acpi.h
+++ b/arch/x86/include/asm/acpi.h
@@ -113,7 +113,6 @@ static inline void acpi_disable_pci(void)
         acpi_pci_disabled = 1;
         acpi_noirq_set();
 }
-extern int acpi_irq_balance_set(char *str);
 
 /* routines for saving/restoring kernel state */
 extern int acpi_save_state_mem(void);
diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c
index 8c1f76abae9e..4c51a2f8fd31 100644
--- a/arch/x86/kernel/acpi/boot.c
+++ b/arch/x86/kernel/acpi/boot.c
@@ -1343,7 +1343,6 @@ static void __init acpi_process_madt(void)
                         error = acpi_parse_madt_ioapic_entries();
                         if (!error) {
                                 acpi_irq_model = ACPI_IRQ_MODEL_IOAPIC;
-                                acpi_irq_balance_set(NULL);
                                 acpi_ioapic = 1;
 
                                 smp_found_config = 1;
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);