diff --git a/sys/kern/kern_clock.c b/sys/kern/kern_clock.c
--- a/sys/kern/kern_clock.c
+++ b/sys/kern/kern_clock.c
@@ -44,6 +44,7 @@
 #include "opt_hwpmc_hooks.h"
 #include "opt_ntp.h"
 #include "opt_watchdog.h"
+#include "opt_acpi.h"
 
 #include <sys/param.h>
 #include <sys/systm.h>
@@ -533,7 +534,10 @@
 			if (i > 0 && i <= newticks)
 				watchdog_fire();
 		}
-		intr_event_handle(clk_intr_event, NULL);
+#ifdef DEV_ACPI
+		if (!CK_SLIST_EMPTY(&clk_intr_event->ie_handlers))
+			intr_event_handle(clk_intr_event, NULL);
+#endif
 	}
 	if (curcpu == CPU_FIRST())
 		cpu_tick_calibration();
diff --git a/sys/kern/kern_intr.c b/sys/kern/kern_intr.c
--- a/sys/kern/kern_intr.c
+++ b/sys/kern/kern_intr.c
@@ -32,6 +32,7 @@
 #include "opt_ddb.h"
 #include "opt_hwpmc_hooks.h"
 #include "opt_kstack_usage_prof.h"
+#include "opt_acpi.h"
 
 #include <sys/param.h>
 #include <sys/bus.h>
@@ -88,7 +89,9 @@
 	uintptr_t event;
 };
 
+#ifdef DEV_ACPI
 struct	intr_event *clk_intr_event;
+#endif
 struct proc *intrproc;
 
 static MALLOC_DEFINE(M_ITHREAD, "ithread", "Interrupt Threads");
@@ -1618,6 +1621,7 @@
 }
 #endif /* DDB */
 
+#ifdef DEV_ACPI
 /*
  * Start standard software interrupt threads
  */
@@ -1631,6 +1635,7 @@
 }
 SYSINIT(start_softintr, SI_SUB_SOFTINTR, SI_ORDER_FIRST, start_softintr,
     NULL);
+#endif
 
 /*
  * Sysctls used by systat and others: hw.intrnames and hw.intrcnt.
diff --git a/sys/sys/interrupt.h b/sys/sys/interrupt.h
--- a/sys/sys/interrupt.h
+++ b/sys/sys/interrupt.h
@@ -152,7 +152,9 @@
 
 struct proc;
 
+#ifdef DEV_ACPI
 extern struct	intr_event *clk_intr_event;
+#endif
 
 /* Counts and names for statistics (defined in MD code). */
 extern u_long 	*intrcnt;	/* counts for each device and stray */
diff --git a/sys/x86/x86/mp_x86.c b/sys/x86/x86/mp_x86.c
--- a/sys/x86/x86/mp_x86.c
+++ b/sys/x86/x86/mp_x86.c
@@ -1663,7 +1663,10 @@
 ipi_swi_handler(struct trapframe frame)
 {
 
-	intr_event_handle(clk_intr_event, &frame);
+#ifdef DEV_ACPI
+	if (!CK_SLIST_EMPTY(&clk_intr_event->ie_handlers))
+		intr_event_handle(clk_intr_event, &frame);
+#endif
 }
 
 /*