range constraint for realtime-priority engine parameter

git-svn-id: http://subversion.jackaudio.org/jack/jack2/trunk/jackmp@3011 0c269be4-1314-0410-8aa9-9f06e86f4224

common/JackControlAPI.cpp

@@ -591,6 +591,29 @@ jackctl_wait_signals(sigset_t signals)
 }
 #endif
 
+static
+jack_driver_param_constraint_desc_t *
+get_realtime_priority_constraint()
+{
+    jack_driver_param_constraint_desc_t * constraint_ptr;
+    int min, max;
+
+    if (!jack_get_thread_realtime_priority_range(&min, &max))
+    {
+        return NULL;
+    }
+
+    //jack_info("realtime priority range is (%d,%d)", min, max);
+
+    constraint_ptr = (jack_driver_param_constraint_desc_t *)calloc(1, sizeof(jack_driver_param_value_enum_t));
+    constraint_ptr->flags = JACK_CONSTRAINT_FLAG_RANGE;
+
+    constraint_ptr->constraint.range.min.i = min;
+    constraint_ptr->constraint.range.max.i = max;
+
+    return constraint_ptr;
+}
+
 EXPORT jackctl_server_t * jackctl_server_create()
 {
     struct jackctl_server * server_ptr;
@@ -645,7 +668,8 @@ EXPORT jackctl_server_t * jackctl_server_create()
             JackParamInt,
             &server_ptr->realtime_priority,
             &server_ptr->default_realtime_priority,
-            value) == NULL)
+            value,
+            get_realtime_priority_constraint()) == NULL)
     {
         goto fail_free_parameters;
     }

common/JackThread.h

@@ -114,6 +114,8 @@ class SERVER_EXPORT JackThreadInterface
 
 } // end of namespace
 
+bool jack_get_thread_realtime_priority_range(int * min_ptr, int * max_ptr);
+
 bool jack_tls_allocate_key(jack_tls_key *key_ptr);
 bool jack_tls_free_key(jack_tls_key key);
 

posix/JackPosixThread.cpp

@@ -22,6 +22,10 @@ Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 #include "JackError.h"
 #include "JackTime.h"
 #include <string.h> // for memset
+#include <unistd.h> // for _POSIX_PRIORITY_SCHEDULING check
+
+#define JACK_SCHED_POLICY SCHED_RR
+//#define JACK_SCHED_POLICY SCHED_FIFO
 
 namespace Jack
 {
@@ -114,8 +118,7 @@ int JackPosixThread::StartImp(pthread_t* thread, int priority, int realtime, voi
             return -1;
     	}
     
-        //if ((res = pthread_attr_setschedpolicy(&attributes, SCHED_FIFO))) {
-        if ((res = pthread_attr_setschedpolicy(&attributes, SCHED_RR))) {
+        if ((res = pthread_attr_setschedpolicy(&attributes, JACK_SCHED_POLICY))) {
             jack_error("Cannot set RR scheduling class for RT thread res = %d err = %s", res, strerror(errno));
             return -1;
         }
@@ -216,9 +219,7 @@ int JackPosixThread::AcquireRealTimeImp(pthread_t thread, int priority)
     memset(&rtparam, 0, sizeof(rtparam));
     rtparam.sched_priority = priority;
 
-    //if ((res = pthread_setschedparam(fThread, SCHED_FIFO, &rtparam)) != 0) {
-
-    if ((res = pthread_setschedparam(thread, SCHED_RR, &rtparam)) != 0) {
+    if ((res = pthread_setschedparam(thread, JACK_SCHED_POLICY, &rtparam)) != 0) {
         jack_error("Cannot use real-time scheduling (RR/%d) "
                    "(%d: %s)", rtparam.sched_priority, res,
                    strerror(res));
@@ -265,6 +266,34 @@ SERVER_EXPORT void ThreadExit()
 
 } // end of namespace
 
+bool jack_get_thread_realtime_priority_range(int * min_ptr, int * max_ptr)
+{
+#if defined(_POSIX_PRIORITY_SCHEDULING) && !defined(__APPLE__)
+    int min, max;
+
+    min = sched_get_priority_min(JACK_SCHED_POLICY);
+    if (min == -1)
+    {
+        jack_error("sched_get_priority_min() failed.");
+        return false;
+    }
+
+    max = sched_get_priority_max(JACK_SCHED_POLICY);
+    if (max == -1)
+    {
+        jack_error("sched_get_priority_max() failed.");
+        return false;
+    }
+
+    *min_ptr = min;
+    *max_ptr = max;
+
+    return true;
+#else
+    return false;
+#endif
+}
+
 bool jack_tls_allocate_key(jack_tls_key *key_ptr)
 {
     int ret;

windows/JackWinThread.cpp

@@ -232,6 +232,11 @@ SERVER_EXPORT void ThreadExit()
 
 } // end of namespace
 
+bool jack_get_thread_realtime_priority_range(int * min_ptr, int * max_ptr)
+{
+    return false;
+}
+
 bool jack_tls_allocate_key(jack_tls_key *key_ptr)
 {
     DWORD key;