# HG changeset patch
# User Ryan C. Gordon <icculus@icculus.org>
# Date 1429546964 14400
# Node ID 7454bfce92024d4ad50540bbaaf53d57e965ec3e
# Parent  5378812427567d00a19f0119ea22dda11734e7ff
Windows: Always set the system timer resolution to 1ms by default.

An existing hint lets apps that don't need the timer resolution changed avoid
this, to save battery, etc, but this fixes several problems in timing, audio
callbacks not firing fast enough, etc.

Fixes Bugzilla #2944.

diff -r 537881242756 -r 7454bfce9202 src/timer/windows/SDL_systimer.c
--- a/src/timer/windows/SDL_systimer.c	Thu Apr 16 22:04:35 2015 +0200
+++ b/src/timer/windows/SDL_systimer.c	Mon Apr 20 12:22:44 2015 -0400
@@ -43,7 +43,7 @@
 
 #ifndef __WINRT__
 static void
-timeSetPeriod(UINT uPeriod)
+timeSetPeriod(const UINT uPeriod)
 {
     static UINT timer_period = 0;
 
@@ -87,6 +87,11 @@
     }
     ticks_started = SDL_TRUE;
 
+    /* if we didn't set a precision, set it high. This affects lots of things
+       on Windows besides the SDL timers, like audio callbacks, etc. */
+    SDL_AddHintCallback(SDL_HINT_TIMER_RESOLUTION,
+                        SDL_TimerResolutionChanged, NULL);
+
     /* Set first ticks value */
 #ifdef USE_GETTICKCOUNT
     start = GetTickCount();
@@ -102,11 +107,7 @@
 #ifdef __WINRT__
         start = 0;            /* the timer failed to start! */
 #else
-        timeSetPeriod(1);     /* use 1 ms timer precision */
         start = timeGetTime();
-
-        SDL_AddHintCallback(SDL_HINT_TIMER_RESOLUTION,
-                            SDL_TimerResolutionChanged, NULL);
 #endif /* __WINRT__ */
     }
 #endif /* USE_GETTICKCOUNT */
@@ -120,12 +121,14 @@
 #ifndef __WINRT__
         SDL_DelHintCallback(SDL_HINT_TIMER_RESOLUTION,
                             SDL_TimerResolutionChanged, NULL);
-
-        timeSetPeriod(0);
 #endif /* __WINRT__ */
     }
 #endif /* USE_GETTICKCOUNT */
 
+#ifndef __WINRT__
+    timeSetPeriod(0);  /* always release our timer resolution request. */
+#endif
+
     ticks_started = SDL_FALSE;
 }