[PATCH] doc/guides/rel_notes: Add known issue for IOMMU attributes read

[Rosen Xu <rosen.xu@intel.com>]

Read IOMMU attributes from linux kernle 4.10.0 error.

Cc: stable@dpdk.org

Signed-off-by: Rosen Xu <rosen.xu@intel.com>
---
 doc/guides/rel_notes/known_issues.rst | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/doc/guides/rel_notes/known_issues.rst b/doc/guides/rel_notes/known_issues.rst
index afcc2c4..74876ff 100644
--- a/doc/guides/rel_notes/known_issues.rst
+++ b/doc/guides/rel_notes/known_issues.rst
@@ -714,3 +714,24 @@ igb_uio can not be used when running l3fwd-power
 
 **Driver/Module**:
    ``igb_uio`` module.
+
+
+linux kernel iommu attribute read error
+---------------------------------------
+
+**Description**:
+   Read immu attributes from /sys/devices/virtual/iommu/dmarXXX/intel-iommu/cap in linux kernel
+   4.10.0 error. That because the link between the iommu sysfs-device and the struct intel_iommu
+   is no longer stored as driver-data.
+
+**Implication**:
+   When insmod ``vfio-pci`` and running testpmd APP, it doesn't initiate properly.
+
+**Resolution/Workaround**:
+   Use other linux kernel version. It only happens in linux kernel 4.10.0.
+
+**Affected Environment/Platform**:
+   ALL OS of linux kernel 4.10.0.
+
+**Driver/Module**:
+   ``vfio-pci`` module.
-- 
1.8.3.1