skiboot 5.10.4 release notes

Signed-off-by: Stewart Smith <stewart@linux.ibm.com>
(cherry picked from commit 604f758)
Signed-off-by: Stewart Smith <stewart@linux.ibm.com>

doc/release-notes/skiboot-5.10.4.rst

@@ -0,0 +1,28 @@
+.. _skiboot-5.10.4:
+
+==============
+skiboot-5.10.4
+==============
+
+skiboot 5.10.4 was released on Wednesday April 4th, 2018. It replaces
+:ref:`skiboot-5.10.3` as the current stable release in the 5.10.x series.
+
+It is recommended that 5.10.3 be used instead of any previous 5.10.x version
+due to the bug fixes and debugging enhancements in it.
+
+Over :ref:`skiboot-5.10.3`, we have one bug fix:
+
+- xive: disable store EOI support
+
+  Hardware has limitations which would require to put a sync after each
+  store EOI to make sure the MMIO operations that change the ESB state
+  are ordered. This is a killer for performance and the PHBs do not
+  support the sync. So remove the store EOI for the moment, until
+  hardware is improved.
+
+  Also, while we are at changing the XIVE source flags, let's fix the
+  settings for the PHB4s which should follow these rules :
+
+  - SHIFT_BUG    for DD10
+  - STORE_EOI    for DD20 and if enabled
+  - TRIGGER_PAGE for DDx0 and if not STORE_EOI