diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index 7235c48..43856d1 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -217,6 +217,7 @@
 
 int acpi_pci_irq_enable (struct pci_dev *dev);
 void acpi_penalize_isa_irq(int irq, int active);
+bool acpi_isa_irq_available(int irq);
 void acpi_penalize_sci_irq(int irq, int trigger, int polarity);
 void acpi_pci_irq_disable (struct pci_dev *dev);