+ /* HOST_IRQ_STAT behaves as level triggered latch meaning that
+ * it should be cleared after all the port events are cleared;
+ * otherwise, it will raise a spurious interrupt after each
+ * valid one. Please read section 10.6.2 of ahci 1.1 for more
+ * information.
+ *
+ * Also, use the unmasked value to clear interrupt as spurious
+ * pending event on a dummy port might cause screaming IRQ.
+ */
+ writel(irq_stat, mmio + HOST_IRQ_STAT);
+