diff --git a/man2/reboot.2 b/man2/reboot.2
index ee5064863..c3d8d252f 100644
--- a/man2/reboot.2
+++ b/man2/reboot.2
@@ -139,6 +139,12 @@ is performed immediately.
 If not preceded by a
 .BR sync (2),
 data will be lost.
+.TP
+.BR LINUX_REBOOT_CMD_SW_SUSPEND 
+(0xd000fce2; since Linux 2.5.18).
+The system is suspended (hibernated) to disk.
+This option is available only if the kernel was configured with
+.BR CONFIG_HIBERNATION .
 .LP
 Only the superuser may call
 .BR reboot ().