diff --git a/drivers/rtc/rtc-cmos.c b/drivers/rtc/rtc-cmos.c
index 0743c6acd6e2..9cc1c3b53c4b 100644
--- a/drivers/rtc/rtc-cmos.c
+++ b/drivers/rtc/rtc-cmos.c
@@ -1493,9 +1493,18 @@ static int __init cmos_platform_probe(struct platform_device *pdev)
 		resource = platform_get_resource(pdev, IORESOURCE_IO, 0);
 	else
 		resource = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	irq = platform_get_irq(pdev, 0);
-	if (irq < 0)
+	irq = platform_get_irq_optional(pdev, 0);
+	if (irq < 0) {
 		irq = -1;
+#ifdef CONFIG_X86
+		/*
+		 * On some x86 systems, the IRQ is not defined, but it should
+		 * always be safe to hardcode it on systems with a legacy PIC.
+		 */
+		if (nr_legacy_irqs())
+			irq = RTC_IRQ;
+#endif
+	}
 
 	return cmos_do_probe(&pdev->dev, resource, irq);
 }