diff --git a/arch/ia64/kernel/acpi.c b/arch/ia64/kernel/acpi.c
index ef2fe47..29f05d4 100644
--- a/arch/ia64/kernel/acpi.c
+++ b/arch/ia64/kernel/acpi.c
@@ -609,6 +609,9 @@
 
 void acpi_unregister_gsi(u32 gsi)
 {
+	if (acpi_irq_model == ACPI_IRQ_MODEL_PLATFORM)
+		return;
+
 	iosapic_unregister_intr(gsi);
 }