Configurable CA priority of PVAttribute (areaDetector#491)

xiaoqiangwang · May 24, 2023 · 954e57f · 954e57f
1 parent 49f9cce
commit 954e57f
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Showing 4 changed files with 20 additions and 4 deletions.
diff --git a/ADApp/ADSrc/PVAttribute.cpp b/ADApp/ADSrc/PVAttribute.cpp
@@ -33,9 +33,10 @@ static asynUser *pasynUserSelf = NULL;
   * \param[in] dbrType The EPICS DBR_XXX type to be used (DBR_STRING, DBR_DOUBLE, etc).
   *                    In addition to the normal DBR types a special type, DBR_NATIVE, may be used,
   *                    which means to use the native data type returned by Channel Access for this PV.
+  * \param[in] priority The priority level of the CA channel, 0 the lowest and 99 the highest.
   */
 PVAttribute::PVAttribute(const char *pName, const char *pDescription,
-                         const char *pSource, chtype dbrType)
+                         const char *pSource, chtype dbrType, int priority)
     : NDAttribute(pName, pDescription, NDAttrSourceEPICSPV, pSource, NDAttrUndefined, 0),
     dbrType(dbrType), callbackString(0), connectedOnce(false)
 {
@@ -63,7 +64,7 @@ PVAttribute::PVAttribute(const char *pName, const char *pDescription,
         return;
     }
     /* Set connection callback on this PV */
-    SEVCHK(ca_create_channel(pSource, connectCallbackC, this, 10 ,&this->chanId),
+    SEVCHK(ca_create_channel(pSource, connectCallbackC, this, priority, &this->chanId),
            "ca_create_channel");
 }
 

diff --git a/ADApp/ADSrc/PVAttribute.h b/ADApp/ADSrc/PVAttribute.h
@@ -24,7 +24,7 @@
   */
 class ADCORE_API PVAttribute : public NDAttribute {
 public:
-    PVAttribute(const char *pName, const char *pDescription, const char *pSource, chtype dbrType);
+    PVAttribute(const char *pName, const char *pDescription, const char *pSource, chtype dbrType, int priority);
     PVAttribute(PVAttribute& attribute);
     ~PVAttribute();
     PVAttribute* copy(NDAttribute *pAttribute);

diff --git a/ADApp/ADSrc/asynNDArrayDriver.cpp b/ADApp/ADSrc/asynNDArrayDriver.cpp
@@ -19,6 +19,7 @@
 
 #include <libxml/parser.h>
 
+#include <epicsAlgorithm.h>
 #include <epicsString.h>
 #include <epicsThread.h>
 #include <macLib.h>
@@ -429,11 +430,16 @@ asynStatus asynNDArrayDriver::readNDAttributesFile()
                    return asynError;
                 }
             }
+            // CA priority level
+            const char *pPriority = (const char *)xmlGetProp(Attr, (const xmlChar *)"priority");
+            int priority = 10;
+            if (pPriority) priority = epicsMin(99L, epicsMax(0L, strtol(pPriority, NULL, 0)));
+
             asynPrint(pasynUserSelf, ASYN_TRACEIO_DRIVER,
                 "%s:%s: Name=%s, PVName=%s, pDBRType=%s, dbrType=%d, pDescription=%s\n",
                 driverName, functionName, pName, pSource, pDBRType, dbrType, pDescription);
 #ifndef EPICS_LIBCOM_ONLY
-            PVAttribute *pPVAttribute = new PVAttribute(pName, pDescription, pSource, dbrType);
+            PVAttribute *pPVAttribute = new PVAttribute(pName, pDescription, pSource, dbrType, priority);
             this->pAttributeList->add(pPVAttribute);
 #endif
         } else if (strcmp(pAttrType, NDAttribute::attrSourceString(NDAttrSourceParam)) == 0) {

diff --git a/XML_schema/NDAttributes.xsd b/XML_schema/NDAttributes.xsd
@@ -73,6 +73,15 @@
           </xs:documentation>
         </xs:annotation>
       </xs:attribute>
+      <xs:attribute name="priority" type="xs:int" default="10">
+        <!-- only for type="EPICS_PV" -->
+        <xs:annotation>
+          <xs:documentation>
+            Declares the dispatch priority within the server for an
+            EPICS Process Variable.
+          </xs:documentation>
+        </xs:annotation>
+      </xs:attribute>
       <xs:attribute name="param" type="xs:string" default="">
         <!-- only for type="FUNCTION" -->
         <xs:annotation>