diff --git a/arch/ia64/kernel/acpi.c b/arch/ia64/kernel/acpi.c
index 6ff6815d34ef9166be93f4580829416a54ff7ffd..853d1f11be005f9e0b3443d8b33cdcbd72e53edd 100644
--- a/arch/ia64/kernel/acpi.c
+++ b/arch/ia64/kernel/acpi.c
@@ -627,6 +627,9 @@ void acpi_unregister_gsi(u32 gsi)
 	if (acpi_irq_model == ACPI_IRQ_MODEL_PLATFORM)
 		return;
 
+	if (has_8259 && gsi < 16)
+		return;
+
 	iosapic_unregister_intr(gsi);
 }