add BUSY retval

Reviewed-on: #139

src/fsfw/devicehandlers/DeviceCommunicationIF.h

@@ -49,6 +49,7 @@ class DeviceCommunicationIF {
   // is this needed if there is no open/close call?
   static const ReturnValue_t NOT_ACTIVE = MAKE_RETURN_CODE(0x05);
   static const ReturnValue_t TOO_MUCH_DATA = MAKE_RETURN_CODE(0x06);
+  static constexpr ReturnValue_t BUSY = MAKE_RETURN_CODE(0x07);
 
   virtual ~DeviceCommunicationIF() {}
 

src/fsfw/osal/linux/PosixThread.cpp

@@ -179,8 +179,8 @@ void PosixThread::createTask(void* (*fnc_)(void*), void* arg_) {
 #error "Please define FSFW_USE_REALTIME_FOR_LINUX with either 0 or 1"
 #endif
 #if FSFW_USE_REALTIME_FOR_LINUX == 1
-  // FIFO -> This needs root privileges for the process
+  // RR -> This needs root privileges for the process
-  status = pthread_attr_setschedpolicy(&attributes, SCHED_FIFO);
+  status = pthread_attr_setschedpolicy(&attributes, SCHED_RR);
   if (status != 0) {
     utility::printUnixErrorGeneric(CLASS_NAME, "createTask", "pthread_attr_setschedpolicy");
   }