X-Git-Url: https://gerrit.fd.io/r/gitweb?p=deb_dpdk.git;a=blobdiff_plain;f=doc%2Fguides%2Fnics%2Fi40e.rst;fp=doc%2Fguides%2Fnics%2Fi40e.rst;h=cd468748f8ae539df25c5cfe26302cd7d41881f3;hp=bc200d39d37cf54342948449ca0402eb898afc8a;hb=055c52583a2794da8ba1e85a48cce3832372b12f;hpb=f239aed5e674965691846e8ce3f187dd47523689

diff --git a/doc/guides/nics/i40e.rst b/doc/guides/nics/i40e.rst
index bc200d39..cd468748 100644
--- a/doc/guides/nics/i40e.rst
+++ b/doc/guides/nics/i40e.rst
@@ -78,6 +78,8 @@ Prerequisites
 - To get better performance on Intel platforms, please follow the "How to get best performance with NICs on Intel platforms"
   section of the :ref:`Getting Started Guide for Linux <linux_gsg>`.
 
+- Upgrade the NVM/FW version following the `Intel® Ethernet NVM Update Tool Quick Usage Guide for Linux
+  <https://www-ssl.intel.com/content/www/us/en/embedded/products/networking/nvm-update-tool-quick-linux-usage-guide.html>`_ if needed.
 
 Pre-Installation Configuration
 ------------------------------
@@ -396,13 +398,24 @@ used to classify MPLS packet by using a command in testpmd like:
    testpmd> ethertype_filter 0 add mac_ignr 00:00:00:00:00:00 ethertype \
             0x8847 fwd queue <M>
 
-16 Byte Descriptor cannot be used on DPDK VF
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+16 Byte RX Descriptor setting on DPDK VF
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
-If the Linux i40e kernel driver is used as host driver, while DPDK i40e PMD
-is used as the VF driver, DPDK cannot choose 16 byte receive descriptor. That
-is to say, user should keep ``CONFIG_RTE_LIBRTE_I40E_16BYTE_RX_DESC=n`` in
-config file.
+Currently the VF's RX descriptor mode is decided by PF. There's no PF-VF
+interface for VF to request the RX descriptor mode, also no interface to notify
+VF its own RX descriptor mode.
+For all available versions of the i40e driver, these drivers don't support 16
+byte RX descriptor. If the Linux i40e kernel driver is used as host driver,
+while DPDK i40e PMD is used as the VF driver, DPDK cannot choose 16 byte receive
+descriptor. The reason is that the RX descriptor is already set to 32 byte by
+the i40e kernel driver. That is to say, user should keep
+``CONFIG_RTE_LIBRTE_I40E_16BYTE_RX_DESC=n`` in config file.
+In the future, if the Linux i40e driver supports 16 byte RX descriptor, user
+should make sure the DPDK VF uses the same RX descriptor mode, 16 byte or 32
+byte, as the PF driver.
+
+The same rule for DPDK PF + DPDK VF. The PF and VF should use the same RX
+descriptor mode. Or the VF RX will not work.
 
 Receive packets with Ethertype 0x88A8
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
@@ -465,6 +478,11 @@ enabled using the steps below.
 
       setpci -s <XX:XX.X> a8.w=<value>
 
+Vlan strip of VF
+~~~~~~~~~~~~~~~~
+
+The VF vlan strip function is only supported in the i40e kernel driver >= 2.1.26.
+
 High Performance of Small Packets on 40G NIC
 --------------------------------------------