diff --git a/qemu/hw/mc146818rtc.c b/qemu/hw/mc146818rtc.c
index e1e6427..fd00f3a 100644
--- a/qemu/hw/mc146818rtc.c
+++ b/qemu/hw/mc146818rtc.c
@@ -72,6 +72,7 @@ struct RTCState {
 
 static void rtc_set_time(RTCState *s);
 static void rtc_copy_date(RTCState *s);
+static void rtc_catchup(RTCState *s);
 
 static void rtc_timer_update(RTCState *s, int64_t current_time)
 {
@@ -108,6 +109,8 @@ static void cmos_ioport_write(void *opaque, uint32_t addr, uint32_t data)
 {
     RTCState *s = opaque;
 
+    rtc_catchup(s);
+
     if ((addr & 1) == 0) {
         s->cmos_index = data & 0x7f;
     } else {
@@ -334,13 +337,48 @@ static void rtc_update_second2(void *opaque)
     s->cmos_data[RTC_REG_A] &= ~REG_A_UIP;
 
     s->next_second_time += ticks_per_sec;
-    qemu_mod_timer(s->second_timer, s->next_second_time);
+
+    /* Keep going only if interrupts are needed */
+    if (s->cmos_data[RTC_REG_B] & (REG_B_AIE | REG_B_UIE)) {
+        qemu_mod_timer(s->second_timer, s->next_second_time);
+    }
+}
+
+static void rtc_catchup(RTCState *s)
+{
+    int64_t now;
+
+    if (!qemu_timer_pending(s->second_timer) &&
+        !qemu_timer_pending(s->second_timer2)) {
+
+        /* Count the seconds passed since last access */
+        now = qemu_get_clock(vm_clock);
+
+        while (s->next_second_time <= now) {
+            rtc_next_second(&s->current_tm);
+            s->next_second_time += ticks_per_sec;
+        }
+
+        if (!(s->cmos_data[RTC_REG_B] & REG_B_SET)) {
+            rtc_copy_date(s);
+        }
+
+        /* Restart the right timer */
+        if ((s->next_second_time - now) < ticks_per_sec/100) {
+            rtc_update_second(s);
+        } else {
+            qemu_mod_timer(s->second_timer, s->next_second_time);
+        }
+    }
 }
 
 static uint32_t cmos_ioport_read(void *opaque, uint32_t addr)
 {
     RTCState *s = opaque;
     int ret;
+
+    rtc_catchup(s);
+
     if ((addr & 1) == 0) {
         return 0xff;
     } else {