Changeset 21933 for trunk/src/winmm/os2timer.cpp

Timestamp:

Dec 30, 2011, 11:41:30 AM (14 years ago)

Author:

dmik

Message:

winmm: Restore normal priority when calling timer funciton.

This should prevent the callback code from working at the high
priority used for waiting on timer signals.

File:

• trunk/src/winmm/os2timer.cpp (modified) (4 diffs)

trunk/src/winmm/os2timer.cpp

@@ -423 +423 @@
   ULONG   Count = 0;
   APIRET  rc = 0;       /* Return code  */
-  USHORT  selTIB;
 
   dprintf(("WINMM: TimerHandler thread created (%08xh)\n",
            this));
 
-  rc = DosSetPriority (PRTYS_THREAD,        /* Change a single thread */
-                       PRTYC_TIMECRITICAL,  /* Time critical class    */
-                       0L,                  /* Increase by 15         */
-                       0L);                 /* Assume current thread  */
+  // save the current thread priority
+  PTIB ptib = NULL;
+  DosGetInfoBlocks(&ptib, NULL);
+  ULONG prio = ptib->tib_ptib2->tib2_ulpri;
+
+  // increase the thread priority to improve timer resolution
+  DosSetPriority (PRTYS_THREAD, PRTYC_TIMECRITICAL, 0, 0);
 
   while(!fFatal)
@@ -438 +440 @@
              dwFlags,
             clientCallback));
-    
+
     rc = DosWaitEventSem(TimerSem, SEM_INDEFINITE_WAIT);
     if(rc) {
@@ -451 +453 @@
     if(!fFatal)
     {
-        // @@@PH: we're calling the client with PRTYC_TIMECRITICAL !!!
-        //        It'd be much nicer to call with original priority!
-      
         // check timer running condition
         if (TimerStatus == Running)
@@ -467 +466 @@
               if (clientCallback != NULL)
               {
+                  // restore the original priority (we never know what the callback
+                  // code does)
+                  DosSetPriority (PRTYS_THREAD, (prio >> 8) & 0xFF, 0, 0);
+
                   clientCallback((UINT)timerID, 0, userData, 0, 0);
+
+                  DosSetPriority (PRTYS_THREAD, PRTYC_TIMECRITICAL, 0, 0);
               }
               break;