diff --git a/hw/timer/puv3_ost.c b/hw/timer/puv3_ost.c
index 0898da5ce9..697519593b 100644
--- a/hw/timer/puv3_ost.c
+++ b/hw/timer/puv3_ost.c
@@ -13,7 +13,6 @@
 #include "hw/sysbus.h"
 #include "hw/irq.h"
 #include "hw/ptimer.h"
-#include "qemu/main-loop.h"
 #include "qemu/module.h"
 
 #undef DEBUG_PUV3
@@ -27,7 +26,6 @@ typedef struct PUV3OSTState {
     SysBusDevice parent_obj;
 
     MemoryRegion iomem;
-    QEMUBH *bh;
     qemu_irq irq;
     ptimer_state *ptimer;
 
@@ -68,6 +66,7 @@ static void puv3_ost_write(void *opaque, hwaddr offset,
     DPRINTF("offset 0x%x, value 0x%x\n", offset, value);
     switch (offset) {
     case 0x00: /* Match Register 0 */
+        ptimer_transaction_begin(s->ptimer);
         s->reg_OSMR0 = value;
         if (s->reg_OSMR0 > s->reg_OSCR) {
             ptimer_set_count(s->ptimer, s->reg_OSMR0 - s->reg_OSCR);
@@ -76,6 +75,7 @@ static void puv3_ost_write(void *opaque, hwaddr offset,
                     (0xffffffff - s->reg_OSCR));
         }
         ptimer_run(s->ptimer, 2);
+        ptimer_transaction_commit(s->ptimer);
         break;
     case 0x14: /* Status Register */
         assert(value == 0);
@@ -128,9 +128,10 @@ static void puv3_ost_realize(DeviceState *dev, Error **errp)
 
     sysbus_init_irq(sbd, &s->irq);
 
-    s->bh = qemu_bh_new(puv3_ost_tick, s);
-    s->ptimer = ptimer_init_with_bh(s->bh, PTIMER_POLICY_DEFAULT);
+    s->ptimer = ptimer_init(puv3_ost_tick, s, PTIMER_POLICY_DEFAULT);
+    ptimer_transaction_begin(s->ptimer);
     ptimer_set_freq(s->ptimer, 50 * 1000 * 1000);
+    ptimer_transaction_commit(s->ptimer);
 
     memory_region_init_io(&s->iomem, OBJECT(s), &puv3_ost_ops, s, "puv3_ost",
             PUV3_REGS_OFFSET);