doc: fix mark action zero value in mlx5 guide

The zero value in flow MARK action is reported in Rx datapath
as tagged with zero FDIR ID. Once packet is marked in flow engine
it will be always reported as tagged. For metadata only the zero
value means there is "no metadata" in the packet and the metadata
flag is not set for the case.

Fixes: 3ceeed9f7855 ("doc: update flow mark action in mlx5 guide")
Cc: stable@dpdk.org
Signed-off-by: Viacheslav Ovsiienko <viacheslavo@nvidia.com>

diff --git a/doc/guides/nics/mlx5.rst b/doc/guides/nics/mlx5.rst
index 51d81a0..ff5c8c1 100644 (file)
--- a/doc/guides/nics/mlx5.rst
+++ b/doc/guides/nics/mlx5.rst
@@ -875,8 +875,10 @@ Driver options
   of the extensive metadata features. The legacy Verbs supports FLAG and
   MARK metadata actions over NIC Rx steering domain only.
 
-  The setting MARK or META value to zero means there is no item provided and
-  receiving datapath will not report in mbufs these items are present.
+  Setting META value to zero in flow action means there is no item provided
+  and receiving datapath will not report in mbufs the metadata are present.
+  Setting MARK value to zero in flow action means the zero FDIR ID value
+  will be reported on packet receiving.
 
   For the MARK action the last 16 values in the full range are reserved for
   internal PMD purposes (to emulate FLAG action). The valid range for the