Index: sys/x86/isa/atrtc.c
===================================================================
--- sys/x86/isa/atrtc.c
+++ sys/x86/isa/atrtc.c
@@ -85,6 +85,7 @@
 
 #ifdef DEV_ACPI
 #define	_COMPONENT	ACPI_TIMER
+static int acpi_rtc_is_present;
 ACPI_MODULE_NAME("ATRTC")
 #endif
 
@@ -203,6 +204,7 @@
 	struct resource *intr_res;
 	void *intr_handler;
 	struct eventtimer et;
+	int is_active;
 #ifdef DEV_ACPI
 	ACPI_HANDLE acpi_handle;
 #endif
@@ -293,7 +295,7 @@
 	if (addr >= ATRTC_LAST_REG || addr + len > ATRTC_LAST_REG)
 		return (false);
 
-	if (is_read) {
+	if (is_read || !(acpi_rtc_is_present)) {
 		/* Reading 0x0C will muck with interrupts */
 		if (addr <= RTC_INTR && addr + len > RTC_INTR)
 			return (false);
@@ -487,6 +489,8 @@
 		sc->et.et_priv = dev;
 		et_register(&sc->et);
 	}
+	sc->is_active = 1;
+
 	return(0);
 }
 
@@ -502,11 +506,14 @@
 atrtc_acpi_attach(device_t dev)
 {
 	int ret;
-
-	ret = atrtc_attach(dev);
-	if (ret)
-		return (ret);
-
+	acpi_rtc_is_present = acpi_DeviceIsPresent(dev);
+	if (acpi_rtc_is_present){
+		ret = atrtc_attach(dev);
+		if (ret)
+			return (ret);
+	}else{
+		device_printf(dev, "disabled in acpi handle. Only address space handler\n");
+	}
 	(void)atrtc_reg_acpi_cmos_handler(dev);
 
 	return (0);
@@ -524,8 +531,9 @@
 static int
 atrtc_resume(device_t dev)
 {
-
-	atrtc_restore();
+	struct atrtc_softc *sc = device_get_softc(dev);
+	if(sc->is_active)
+		atrtc_restore();
 	return(0);
 }