New upstream version 18.11.1

[deb_dpdk.git] / doc / guides / rel_notes / known_issues.rst

diff --git a/doc/guides/rel_notes/known_issues.rst b/doc/guides/rel_notes/known_issues.rst
index 95e4ce6..358dfa3 100644 (file)
--- a/doc/guides/rel_notes/known_issues.rst
+++ b/doc/guides/rel_notes/known_issues.rst
@@ -759,3 +759,105 @@ Netvsc driver and application restart
 
 **Driver/Module**:
    ``uio_hv_generic`` module.
+
+
+PHY link up fails when rebinding i40e NICs to kernel driver
+-----------------------------------------------------------
+
+**Description**:
+   Some kernel drivers are not able to handle the link status correctly
+   after DPDK application sets the PHY to link down.
+
+**Implication**:
+   The link status can't be set to "up" after the NIC is rebound to the
+   kernel driver. Before a DPDK application quits it will invoke the
+   function ``i40e_dev_stop()`` which will sets the PHY to link down. Some
+   kernel drivers may not be able to handle the link status correctly after
+   it retakes control of the device. This is a known PHY link configuration
+   issue in the i40e kernel driver. The fix has been addressed in the 2.7.4 rc
+   version. So if the i40e kernel driver is < 2.7.4 and doesn't have the
+   fix backported it will encounter this issue.
+
+**Resolution/Workaround**:
+   First try to remove and reinsert the i40e kernel driver. If that fails
+   reboot the system.
+
+**Affected Environment/Platform**:
+   All.
+
+**Driver/Module**:
+   Poll Mode Driver (PMD).
+
+
+Restricted vdev ethdev operations supported in secondary process
+----------------------------------------------------------------
+**Description**
+   In current virtual device sharing model, Ethernet device data structure will be
+   shared between primary and secondary process. Only those Ethernet device operations
+   which based on it are workable in secondary process.
+
+**Implication**
+   Some Ethernet device operations like device start/stop will be failed on virtual
+   device in secondary process.
+
+**Affected Environment/Platform**:
+   ALL.
+
+**Driver/Module**:
+   Virtual Device Poll Mode Driver (PMD).
+
+
+Kernel crash when hot-unplug igb_uio device while DPDK application is running
+-----------------------------------------------------------------------------
+
+**Description**:
+   When device has been bound to igb_uio driver and application is running,
+   hot-unplugging the device may cause kernel crash.
+
+**Reason**:
+   When device is hot-unplugged, igb_uio driver will be removed which will destroy UIO resources.
+   Later trying to access any uio resource will cause kernel crash.
+
+**Resolution/Workaround**:
+   If using DPDK for PCI HW hot-unplug, prefer to bind device with VFIO instead of IGB_UIO.
+
+**Affected Environment/Platform**:
+    ALL.
+
+**Driver/Module**:
+   ``igb_uio`` module.
+
+
+AVX-512 support disabled
+------------------------
+
+**Description**:
+   ``AVX-512`` support has been disabled on some conditions.
+   This shouldn't be confused with ``CONFIG_RTE_ENABLE_AVX512`` config option which is already
+   disabled by default. This config option defines if ``AVX-512`` specific implementations of
+   some file to be used or not. What has been disabled is compiler feature to produce ``AVX-512``
+   instructions from any source code.
+
+   On DPDK v18.11 ``AVX-512`` is disabled for all ``GCC`` builds which reported to cause a performance
+   drop.
+
+   On DPDK v19.02 ``AVX-512`` disable scope is reduced to ``GCC`` and ``binutils version 2.30`` based
+   on information accured from the GCC community defect.
+
+**Reason**:
+   Generated ``AVX-512`` code cause crash:
+   https://bugs.dpdk.org/show_bug.cgi?id=97
+   https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88096
+
+**Resolution/Workaround**:
+   * Update ``binutils`` to newer version than ``2.30``.
+
+   OR
+
+   * Use different compiler, like ``clang`` for this case.
+
+**Affected Environment/Platform**:
+    ``GCC`` and ``binutils version 2.30``.
+
+**Driver/Module**:
+    ALL.