More flexible RT priority setup on Windows.

windows/JackMMCSS.cpp

@@ -46,7 +46,7 @@ JackMMCSS::JackMMCSS()
 JackMMCSS::~JackMMCSS()
 {}
 
-int JackMMCSS::MMCSSAcquireRealTime(jack_native_thread_t thread)
+int JackMMCSS::MMCSSAcquireRealTime(jack_native_thread_t thread, int priority)
 {
     if (fHandleTable.find(thread) != fHandleTable.end()) {
         return 0;
@@ -57,7 +57,7 @@ int JackMMCSS::MMCSSAcquireRealTime(jack_native_thread_t thread)
         HANDLE task = ffMMCSSFun1("Pro Audio", &dummy);
         if (task == NULL) {
             jack_error("AvSetMmThreadCharacteristics error : %d", GetLastError());
-        } else if (ffMMCSSFun2(task, AVRT_PRIORITY_CRITICAL)) {
+        } else if (ffMMCSSFun2(task, priority - BASE_REALTIME_PRIORITY)) {
             fHandleTable[thread] = task;
             jack_log("AvSetMmThreadPriority success");
             return 0;

windows/JackMMCSS.h

@@ -36,8 +36,10 @@ typedef enum _AVRT_PRIORITY {
   AVRT_PRIORITY_HIGH,		/* 1 */
   AVRT_PRIORITY_CRITICAL	/* 2 */
 } AVRT_PRIORITY, *PAVRT_PRIORITY;
-
-typedef HANDLE (WINAPI *avSetMmThreadCharacteristics)(LPCTSTR, LPDWORD);
+
+#define BASE_REALTIME_PRIORITY 90
+
+typedef HANDLE (WINAPI *avSetMmThreadCharacteristics)(LPCTSTR, LPDWORD);
 typedef BOOL (WINAPI *avRevertMmThreadCharacteristics)(HANDLE);
 typedef BOOL (WINAPI *avSetMmThreadPriority)(HANDLE, AVRT_PRIORITY);
 
@@ -61,7 +63,7 @@ class SERVER_EXPORT JackMMCSS
         JackMMCSS();
         ~JackMMCSS();
 
-        static int MMCSSAcquireRealTime(jack_native_thread_t thread);
+        static int MMCSSAcquireRealTime(jack_native_thread_t thread, int priority);
         static int MMCSSDropRealTime(jack_native_thread_t thread);
 
 };

windows/JackWinThread.cpp

@@ -202,7 +202,7 @@ int JackWinThread::AcquireRealTimeImp(jack_native_thread_t thread, int priority)
 {
     jack_log("JackWinThread::AcquireRealTimeImp priority = %d", priority);
 
-    if (priority >= 90 && MMCSSAcquireRealTime(thread) == 0) {
+    if (priority >= (BASE_REALTIME_PRIORITY - 1) && MMCSSAcquireRealTime(thread, priority) == 0) {
         jack_log("MMCSS API used to acquire RT for thread");
         return 0;
     } else {