diff --git a/Documentation/filesystems/nfs/nfsroot.txt b/Documentation/filesystems/nfs/nfsroot.txt
index 5efae00f6c7fd82f863939ac2e6f2883a52fee09..1513e5d663fd4c1f497e3abbec8c24fe1e032acb 100644
--- a/Documentation/filesystems/nfs/nfsroot.txt
+++ b/Documentation/filesystems/nfs/nfsroot.txt
@@ -123,10 +123,13 @@ ip=<client-ip>:<server-ip>:<gw-ip>:<netmask>:<hostname>:<device>:<autoconf>:
 
 		Default:  Determined using autoconfiguration.
 
-  <hostname>	Name of the client. May be supplied by autoconfiguration,
-  		but its absence will not trigger autoconfiguration.
-		If specified and DHCP is used, the user provided hostname will
-		be carried in the DHCP request to hopefully update DNS record.
+  <hostname>	Name of the client. If a '.' character is present, anything
+		before the first '.' is used as the client's hostname, and anything
+		after it is used as its NIS domain name. May be supplied by
+		autoconfiguration, but its absence will not trigger autoconfiguration.
+		If specified and DHCP is used, the user-provided hostname (and NIS
+		domain name, if present) will be carried in the DHCP request; this
+		may cause a DNS record to be created or updated for the client.
 
   		Default: Client IP address is used in ASCII notation.