diff --git a/src/sound/snd_opl.c b/src/sound/snd_opl.c
index 488acdc35..bab1a8c3f 100644
--- a/src/sound/snd_opl.c
+++ b/src/sound/snd_opl.c
@@ -175,8 +175,6 @@ opl_write(opl_t *dev, uint16_t port, uint8_t val)
 
 	if (!(dev->flags & FLAG_OPL3))
 		dev->port &= 0x00ff;
-
-	return;
     }
 }
 
diff --git a/src/timer.c b/src/timer.c
index 85264a62a..0920076d3 100644
--- a/src/timer.c
+++ b/src/timer.c
@@ -233,6 +233,8 @@ timer_advance_ex(pc_timer_t *timer, int start)
     } else {
 	if (timer->period > 0.0)
 		timer_do_period(timer, (uint64_t) (timer->period * ((double) TIMER_USEC)), start);
+	else
+		timer_disable(timer);
 	timer->period = 0.0;
 	timer->flags &= ~TIMER_SPLIT;
     }
@@ -256,5 +258,8 @@ timer_on_auto(pc_timer_t *timer, double period)
     if (!timer_inited || (timer == NULL))
 	return;
 
-    timer_on(timer, period, (timer->period == 0.0));
+    if (period > 0.0)
+	timer_on(timer, period, (timer->period == 0.0));
+    else
+	timer_stop(timer);
 }