doc: add i40e limitation of DCB function

This patch adds limitation of DCB function.

Signed-off-by: Beilei Xing <beilei.xing@intel.com>
Acked-by: Marko Kovacevic <marko.kovacevic@intel.com>

diff --git a/doc/guides/nics/i40e.rst b/doc/guides/nics/i40e.rst
index cd46874..2507d5f 100644 (file)
--- a/doc/guides/nics/i40e.rst
+++ b/doc/guides/nics/i40e.rst
@@ -483,6 +483,11 @@ Vlan strip of VF
 
 The VF vlan strip function is only supported in the i40e kernel driver >= 2.1.26.
 
+DCB function
+~~~~~~~~~~~~
+
+DCB works only when RSS is enabled.
+
 High Performance of Small Packets on 40G NIC
 --------------------------------------------