diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c
index d73663a..d42deb3 100644
--- a/drivers/cpuidle/cpuidle.c
+++ b/drivers/cpuidle/cpuidle.c
@@ -67,7 +67,7 @@
 	/* enter the state and update stats */
 	dev->last_residency = target_state->enter(dev, target_state);
 	dev->last_state = target_state;
-	target_state->time += dev->last_residency;
+	target_state->time += (unsigned long long)dev->last_residency;
 	target_state->usage++;
 
 	/* give the governor an opportunity to reflect on the outcome */