[PATCH 1/1] doc: expand description of no-huge and PMD issue

[Stanislaw Kardach <kda@semihalf.com>]

Add more details to the description of a known issue of PMDs not being
usable when --no-huge EAL command line parameter is used. The issue
actually happens whenever there is a need for physical addresses, even
when there is no PMD attached.

Signed-off-by: Stanislaw Kardach <kda@semihalf.com>
---
 doc/guides/rel_notes/known_issues.rst | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/doc/guides/rel_notes/known_issues.rst b/doc/guides/rel_notes/known_issues.rst
index 570550843a..2e0ffbdd93 100644
--- a/doc/guides/rel_notes/known_issues.rst
+++ b/doc/guides/rel_notes/known_issues.rst
@@ -249,11 +249,15 @@ PMD does not work with --no-huge EAL command line parameter
 -----------------------------------------------------------
 
 **Description**:
-   Currently, the DPDK does not store any information about memory allocated by ``malloc()` (for example, NUMA node,
-   physical address), hence PMDs do not work when the ``--no-huge`` command line parameter is supplied to EAL.
+   Currently, the DPDK does not store any information about memory allocated by ``malloc()`` (for example, NUMA node,
+   physical address), hence PMDs do not work when the ``--no-huge`` command line parameter is supplied to EAL. This
+   happens when using non-IOMMU based UIO drivers (i.e. ``igb_uio`` or ``uio_pci_generic``) or when IOVA mode is
+   explicitly set to use physical addresses (via the ``--iova-mode=pa`` EAL parameter).
 
 **Implication**:
-   Sending and receiving data with PMD will not work.
+   Sending and receiving data with PMD will not work. Unit tests checking ``--no-huge`` operation will fail if
+   there is a device bound to the PMD (eal_flags_n_opt_autotest, eal_flags_no_huge_autotest,
+   eal_flags_vdev_opt_autotest, eal_flags_misc_autotest).
 
 **Resolution/Workaround**:
    Use huge page memory or use VFIO to map devices.
-- 
2.30.2