doc: add i40e limitation for flow director

Each PCTYPE can only have one specific FDIR input set at one time.
Add input set requirement info to i40e doc.

Bugzilla ID: 403
Fixes: 14c66a451ef7 ("net/i40e: flush tunnel filters")
Cc: stable@dpdk.org
Signed-off-by: Wei Zhao <wei.zhao1@intel.com>
Acked-by: Beilei Xing <beilei.xing@intel.com>

diff --git a/doc/guides/nics/i40e.rst b/doc/guides/nics/i40e.rst
index 416b390..2f84609 100644 (file)
--- a/doc/guides/nics/i40e.rst
+++ b/doc/guides/nics/i40e.rst
@@ -747,6 +747,15 @@ Use 16 Bytes RX Descriptor Size
 As i40e PMD supports both 16 and 32 bytes RX descriptor sizes, and 16 bytes size can provide helps to high performance of small packets.
 Configuration of ``CONFIG_RTE_LIBRTE_I40E_16BYTE_RX_DESC`` in config files can be changed to use 16 bytes size RX descriptors.
 
+Input set requirement of each pctype for FDIR
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Each PCTYPE can only have one specific FDIR input set at one time.
+For example, if creating 2 rte_flow rules with different input set for one PCTYPE,
+it will fail and return the info "Conflict with the first rule's input set",
+which means the current rule's input set conflicts with the first rule's.
+Remove the first rule if want to change the input set of the PCTYPE.
+
 Example of getting best performance with l3fwd example
 ------------------------------------------------------