From 8a99070ad644bfbb3d5225acb514e543b745524c Mon Sep 17 00:00:00 2001
From: Ron Sluiter <rsluiter@users.noreply.github.com>
Date: Fri, 15 Nov 2013 19:44:42 +0000
Subject: [PATCH] Added bus flushing read on exit from ISR to fix "out of order
 transactions"; symptom "Spurious interrupts".

---
 motorApp/OmsSrc/drvOms.cc | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/motorApp/OmsSrc/drvOms.cc b/motorApp/OmsSrc/drvOms.cc
index b56fd1f1..6ee46d26 100644
--- a/motorApp/OmsSrc/drvOms.cc
+++ b/motorApp/OmsSrc/drvOms.cc
@@ -82,6 +82,8 @@ HeadURL:        $URL$
  * .17  07-26-12 rls - Added reboot flag to IRQ control register. Driver
  *                     sets IRQ_RESET_ID bit on; set_status() and send_mess()
  *                     read IRQ register and disable board if flag is off.
+ * .18  11-15-03 rls - Added bus flushing read on exit from ISR to prevent
+ *                     "out of order transactions".
  */
 
 /*========================stepper motor driver ========================
@@ -900,8 +902,8 @@ static void motorIsr(int card)
         }
         irqdata->recv_sem->signal();
     }
-    /* Update-interrupt state */
-    pmotor->control = control;
+    pmotor->control = control;  /* Update-interrupt state. */
+    control = pmotor->control;  /* Read it back to flush last write cycle. */
 }
 
 static int motorIsrEnable(int card)