diff --git a/arch/ia64/kernel/acpi.c b/arch/ia64/kernel/acpi.c
index 4d1a7e9314cf53c6b76c6d77c453b520365e6855..c6c90f39f4d9e35381cedf30cbd700fd4d7c84cb 100644
--- a/arch/ia64/kernel/acpi.c
+++ b/arch/ia64/kernel/acpi.c
@@ -785,6 +785,14 @@ int acpi_gsi_to_irq(u32 gsi, unsigned int *irq)
 	return 0;
 }
 
+int acpi_isa_irq_to_gsi(unsigned isa_irq, u32 *gsi)
+{
+	if (isa_irq >= 16)
+		return -1;
+	*gsi = isa_irq;
+	return 0;
+}
+
 /*
  *  ACPI based hotplug CPU support
  */
diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c
index cd40aba6aa9563cf5bdb9282fa076ef474d4e163..da718d672596a1844f074a57ea55f77fa996cf72 100644
--- a/arch/x86/kernel/acpi/boot.c
+++ b/arch/x86/kernel/acpi/boot.c
@@ -458,6 +458,14 @@ int acpi_gsi_to_irq(u32 gsi, unsigned int *irq)
 	return 0;
 }
 
+int acpi_isa_irq_to_gsi(unsigned isa_irq, u32 *gsi)
+{
+	if (isa_irq >= 16)
+		return -1;
+	*gsi = isa_irq;
+	return 0;
+}
+
 /*
  * success: return IRQ number (>=0)
  * failure: return < 0
diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index b926afe8c03e7f846043ec78e2bbfb0cc021497e..7a937dabcc4a176d27dfaee061c6b7e3411446e4 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -116,6 +116,7 @@ extern unsigned long acpi_realmode_flags;
 
 int acpi_register_gsi (struct device *dev, u32 gsi, int triggering, int polarity);
 int acpi_gsi_to_irq (u32 gsi, unsigned int *irq);
+int acpi_isa_irq_to_gsi (unsigned isa_irq, u32 *gsi);
 
 #ifdef CONFIG_X86_IO_APIC
 extern int acpi_get_override_irq(int bus_irq, int *trigger, int *polarity);