diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index d8362cf..b182626 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -937,6 +937,8 @@
 
 
 	intel_iommu=	[DMAR] Intel IOMMU driver (DMAR) option
+		on
+			Enable intel iommu driver.
 		off
 			Disable intel iommu driver.
 		igfx_off [Default Off]