commit 40f08e87f613273f9dcc8df7d6a0f574b7d28d05
author Stefan Weil <sw@weilnetz.de> Fri Apr 27 05:34:40 2012 +0000
committer Stefan Weil <sw@weilnetz.de> Thu May 03 07:04:48 2012 +0200
tree 1c69d0f004c24f0e364d60365b7843e49a587b3f
parent f156f2385ff72e05e35edea6bea270033bf2756a

qemu-timer: Fix limits for w32 mmtimer

timeSetEvent only accepts delays in the range which is returned by
timeGetDevCaps.

The lower limit is typically 1 (= 1 ms), so the constant value of 1
in the old code usually worked.

The upper limit can be as low as 10000 ms, so the latest changes in
QEMU's timer handling which introduced timeout values above that limit
could result in failures of timeSetEvent when the timer was re-armed.

Signed-off-by: Stefan Weil <sw@weilnetz.de>

qemu-timer.c

diff --git a/qemu-timer.c b/qemu-timer.c
index 8eadd16..b9fd75d 100644
--- a/qemu-timer.c
+++ b/qemu-timer.c
@@ -611,7 +611,7 @@
 #ifdef _WIN32
 
 static MMRESULT mm_timer;
-static unsigned mm_period;
+static TIMECAPS mm_tc;
 
 static void CALLBACK mm_alarm_handler(UINT uTimerID, UINT uMsg,
                                       DWORD_PTR dwUser, DWORD_PTR dw1,
@@ -628,16 +628,12 @@
 
 static int mm_start_timer(struct qemu_alarm_timer *t)
 {
-    TIMECAPS tc;
+    timeGetDevCaps(&mm_tc, sizeof(mm_tc));
 
-    memset(&tc, 0, sizeof(tc));
-    timeGetDevCaps(&tc, sizeof(tc));
+    timeBeginPeriod(mm_tc.wPeriodMin);
 
-    mm_period = tc.wPeriodMin;
-    timeBeginPeriod(mm_period);
-
-    mm_timer = timeSetEvent(1,                  /* interval (ms) */
-                            mm_period,          /* resolution */
+    mm_timer = timeSetEvent(mm_tc.wPeriodMin,   /* interval (ms) */
+                            mm_tc.wPeriodMin,   /* resolution */
                             mm_alarm_handler,   /* function */
                             (DWORD_PTR)t,       /* parameter */
                             TIME_ONESHOT | TIME_CALLBACK_FUNCTION);
@@ -645,7 +641,7 @@
     if (!mm_timer) {
         fprintf(stderr, "Failed to initialize win32 alarm timer: %ld\n",
                 GetLastError());
-        timeEndPeriod(mm_period);
+        timeEndPeriod(mm_tc.wPeriodMin);
         return -1;
     }
 
@@ -655,23 +651,21 @@
 static void mm_stop_timer(struct qemu_alarm_timer *t)
 {
     timeKillEvent(mm_timer);
-    timeEndPeriod(mm_period);
+    timeEndPeriod(mm_tc.wPeriodMin);
 }
 
 static void mm_rearm_timer(struct qemu_alarm_timer *t, int64_t delta)
 {
     int64_t nearest_delta_ms = delta / 1000000;
-    if (nearest_delta_ms < 1) {
-        nearest_delta_ms = 1;
-    }
-    /* UINT_MAX can be 32 bit */
-    if (nearest_delta_ms > UINT_MAX) {
-        nearest_delta_ms = UINT_MAX;
+    if (nearest_delta_ms < mm_tc.wPeriodMin) {
+        nearest_delta_ms = mm_tc.wPeriodMin;
+    } else if (nearest_delta_ms > mm_tc.wPeriodMax) {
+        nearest_delta_ms = mm_tc.wPeriodMax;
     }
 
     timeKillEvent(mm_timer);
-    mm_timer = timeSetEvent((unsigned int) nearest_delta_ms,
-                            mm_period,
+    mm_timer = timeSetEvent((UINT)nearest_delta_ms,
+                            mm_tc.wPeriodMin,
                             mm_alarm_handler,
                             (DWORD_PTR)t,
                             TIME_ONESHOT | TIME_CALLBACK_FUNCTION);
@@ -680,7 +674,7 @@
         fprintf(stderr, "Failed to re-arm win32 alarm timer %ld\n",
                 GetLastError());
 
-        timeEndPeriod(mm_period);
+        timeEndPeriod(mm_tc.wPeriodMin);
         exit(1);
     }
 }