diff --git a/drivers/dahdi/dahdi-base.c b/drivers/dahdi/dahdi-base.c
index a9cd775..2a5d6f9 100644
--- a/drivers/dahdi/dahdi-base.c
+++ b/drivers/dahdi/dahdi-base.c
@@ -8617,14 +8617,40 @@ static void process_timers(void)
 	spin_unlock(&dahdi_timer_lock);
 }
 
-static unsigned int dahdi_timer_poll(struct file *file, struct poll_table_struct *wait_table)
+/**
+ * dahdi_timer_poll - Poll function for a dahdi_timer.
+ * @file:	Open timer handle.
+ * @wait_table: Just passing through...
+ *
+ * Returns 0 if there isn't anything to wake us up, otherwise POLLPRI if there
+ * is an event waiting on the timer.
+ *
+ * Older versions of Asterisk depend on the behavior that this poll will block
+ * indefintely if the timer has not been configured, so if there is no rate
+ * attached to the timer, this function must return 0.
+ *
+ */
+static unsigned int
+dahdi_timer_poll(struct file *file, struct poll_table_struct *wait_table)
 {
 	struct dahdi_timer *timer = file->private_data;
-	struct dahdi_timer_rate *rate = timer->rate;
+	struct dahdi_timer_rate *rate;
 
-	if (!rate || !timer)
+	if (!timer)
 		return -EINVAL;
 
+	rate = timer->rate;
+
+	if (!rate) {
+		static bool __once;
+		if (!__once) {
+			__once = true;
+			module_printk(KERN_NOTICE,
+				      "Calling poll on unconfigured timer.\n");
+		}
+		return 0;
+	}
+
 	poll_wait(file, &rate->sel, wait_table);
 	if (atomic_read(&timer->tripped) || atomic_read(&timer->ping))
 		return POLLPRI;