--- 70a770ac013875a3e4b5200b954a21197623e2e7
+++ 006466d2a830a34850f6be195cf2c454266b2cf8
@@ -476,6 +476,21 @@ static int hpet_ioctl_ieon(struct hpet_d
 	if (irq) {
 		unsigned long irq_flags;
 
+		if (devp->hd_flags & HPET_SHARED_IRQ) {
+			/*
+			 * To prevent the interrupt handler from seeing an
+			 * unwanted interrupt status bit, program the timer
+			 * so that it will not fire in the near future ...
+			 */
+			writel(readl(&timer->hpet_config) & ~Tn_TYPE_CNF_MASK,
+			       &timer->hpet_config);
+			write_counter(read_counter(&hpet->hpet_mc),
+				      &timer->hpet_compare);
+			/* ... and clear any left-over status. */
+			isr = 1 << (devp - devp->hd_hpets->hp_dev);
+			writel(isr, &hpet->hpet_isr);
+		}
+
 		sprintf(devp->hd_name, "hpet%d", (int)(devp - hpetp->hp_dev));
 		irq_flags = devp->hd_flags & HPET_SHARED_IRQ
 						? IRQF_SHARED : IRQF_DISABLED;
@@ -970,6 +985,8 @@ static int hpet_acpi_add(struct acpi_dev
 		return -ENODEV;
 
 	if (!data.hd_address || !data.hd_nirqs) {
+		if (data.hd_address)
+			iounmap(data.hd_address);
 		printk("%s: no address or irqs in _CRS\n", __func__);
 		return -ENODEV;
 	}