[dpdk-stable] [PATCH] doc: update mlx5 flow MARK action description

[Viacheslav Ovsiienko <viacheslavo@nvidia.com>]

There some limitations added for the MARK action value range.

Fixes: 2d241515ebaf ("net/mlx5: add devarg for extensive metadata support")
Cc: stable@dpdk.org

Signed-off-by: Viacheslav Ovsiienko <viacheslavo@nvidia.com>
---
 doc/guides/nics/mlx5.rst | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/doc/guides/nics/mlx5.rst b/doc/guides/nics/mlx5.rst
index 3bda0f8..3abf0f9 100644
--- a/doc/guides/nics/mlx5.rst
+++ b/doc/guides/nics/mlx5.rst
@@ -825,7 +825,7 @@ Driver options
   +------+-----------+-----------+-------------+-------------+
   | 1    | 24 bits   | vary 0-32 | 32 bits     | yes         |
   +------+-----------+-----------+-------------+-------------+
-  | 2    | vary 0-32 | 32 bits   | 32 bits     | yes         |
+  | 2    | vary 0-24 | 32 bits   | 32 bits     | yes         |
   +------+-----------+-----------+-------------+-------------+
 
   If there is no E-Switch configuration the ``dv_xmeta_en`` parameter is
@@ -837,6 +837,15 @@ 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.
+
+  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
+  MARK action values is 0-0xFFEF for the 16-bit mode and 0-xFFFFEF
+  for the 24-bit mode, the flows with the MARK action value outside
+  the specified range will be rejected.
+
 - ``dv_flow_en`` parameter [int]
 
   A nonzero value enables the DV flow steering assuming it is supported
-- 
1.8.3.1