diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 882a40d..9ca3e74 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1070,6 +1070,9 @@
 				VIA, nVidia)
 			verbose: show contents of HPET registers during setup
 
+	hpet_mmap=	[X86, HPET_MMAP] Allow userspace to mmap HPET
+			registers.  Default set by CONFIG_HPET_MMAP_DEFAULT.
+
 	hugepages=	[HW,X86-32,IA-64] HugeTLB pages to allocate at boot.
 	hugepagesz=	[HW,IA-64,PPC,X86-64] The size of the HugeTLB pages.
 			On x86-64 and powerpc, this option can be specified