[dpdk-dev] [PATCH] doc: add known PHY link up issue for i40e

[Jeff Guo <jia.guo@intel.com>]

When application stop i40e nics and quit itself, if i40e nics be rebinded
from pmd to kernel driver, sometimes PHY can not be link up again any more.

Signed-off-by: Jeff Guo <jia.guo@intel.com>
---
 doc/guides/rel_notes/known_issues.rst | 27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/doc/guides/rel_notes/known_issues.rst b/doc/guides/rel_notes/known_issues.rst
index 95e4ce6..3378bb7 100644
--- a/doc/guides/rel_notes/known_issues.rst
+++ b/doc/guides/rel_notes/known_issues.rst
@@ -759,3 +759,30 @@ Netvsc driver and application restart
 
 **Driver/Module**:
    ``uio_hv_generic`` module.
+
+
+PHY link up failed when rebind i40e nics to kernel driver
+---------------------------------------------------------
+
+**Description**:
+   When application stop i40e nics and quit itself, if i40e nics be rebinded
+   from pmd to kernel driver, sometimes PHY can not be link up again any more.
+
+**Implication**:
+   when DPDK application quit and invoke the function ``i40e_dev_stop``, I40e
+   pmd will set PHY to be link down. After these unexpected configure which not
+   come from kernel driver, it will encounter link configure failure by using
+   kernel driver config tools ``ifconfig``. It is a known PHY link configure
+   synchronous issue in i40e kernel driver. The fix has been addressed in 2.7.4
+   rc version. So if the i40e kernel driver is < 2.7.4 and before the fix be
+   backported into the privous versions, use these kernel drivers will perhaps
+   have this issue.
+
+**Resolution/Workaround**:
+   If it does not help by re-insmod kernel driver, please reboot system.
+
+**Affected E0nvironment/Platform**:
+   All.
+
+**Driver/Module**:
+   Poll Mode Driver (PMD).
-- 
2.7.4