Index: sys/x86/isa/clock.c
===================================================================
--- sys/x86/isa/clock.c	(revision 204309)
+++ sys/x86/isa/clock.c	(working copy)
@@ -97,6 +97,9 @@
 int	i8254_max_count;
 static int i8254_real_max_count;
 
+static int lapic_allclocks;
+TUNABLE_INT("machdep.lapic_allclocks", &lapic_allclocks);
+
 struct mtx clock_lock;
 static	struct intsrc *i8254_intsrc;
 static	u_int32_t i8254_lastcount;
@@ -526,9 +529,24 @@
 void
 cpu_initclocks()
 {
+#if defined(__amd64__) || defined(DEV_APIC)
+	enum lapic_clock tlsca;
+#endif
+	int tasc;
 
+	/* Initialize RTC. */
+	atrtc_start();
+	tasc = atrtc_setup_clock();
+
+	/*
+	 * If the atrtc successfully initialized and the users didn't force
+	 * otherwise use the LAPIC in order to cater hardclock only, otherwise
+	 * take in charge all the clock sources.
+	 */
 #if defined(__amd64__) || defined(DEV_APIC)
-	using_lapic_timer = lapic_setup_clock();
+	tlsca = (lapic_allclocks == 0 && tasc != 0) ? LAPIC_CLOCK_HARDCLOCK :
+	    LAPIC_CLOCK_ALL;
+	using_lapic_timer = lapic_setup_clock(tlsca);
 #endif
 	/*
 	 * If we aren't using the local APIC timer to drive the kernel
@@ -550,9 +568,6 @@
 		set_i8254_freq(i8254_freq, hz);
 	}
 
-	/* Initialize RTC. */
-	atrtc_start();
-
 	/*
 	 * If the separate statistics clock hasn't been explicility disabled
 	 * and we aren't already using the local APIC timer to drive the
@@ -560,7 +575,7 @@
 	 * drive statclock() and profclock().
 	 */
 	if (using_lapic_timer != LAPIC_CLOCK_ALL) {
-		using_atrtc_timer = atrtc_setup_clock();
+		using_atrtc_timer = tasc; 
 		if (using_atrtc_timer) {
 			/* Enable periodic interrupts from the RTC. */
 			intr_add_handler("rtc", 8,
Index: sys/i386/include/apicvar.h
===================================================================
--- sys/i386/include/apicvar.h	(revision 204308)
+++ sys/i386/include/apicvar.h	(working copy)
@@ -259,7 +259,7 @@
 	    enum intr_trigger trigger);
 void	lapic_set_tpr(u_int vector);
 void	lapic_setup(int boot);
-enum lapic_clock	lapic_setup_clock(void);
+enum lapic_clock	lapic_setup_clock(enum lapic_clock srcsdes);
 
 #endif /* !LOCORE */
 #endif /* _MACHINE_APICVAR_H_ */
Index: sys/i386/i386/local_apic.c
===================================================================
--- sys/i386/i386/local_apic.c	(revision 204308)
+++ sys/i386/i386/local_apic.c	(working copy)
@@ -150,6 +150,7 @@
 volatile lapic_t *lapic;
 vm_paddr_t lapic_paddr;
 static u_long lapic_timer_divisor, lapic_timer_period, lapic_timer_hz;
+static enum lapic_clock clockcoverage;
 
 static void	lapic_enable(void);
 static void	lapic_resume(struct pic *pic);
@@ -161,17 +162,6 @@
 
 struct pic lapic_pic = { .pic_resume = lapic_resume };
 
-/*
- * The atrtc device is compiled in only if atpic is present.
- * If it is not, force lapic to take care of all the clocks.
- */
-#ifdef DEV_ATPIC
-static int lapic_allclocks;
-TUNABLE_INT("machdep.lapic_allclocks", &lapic_allclocks);
-#else
-static int lapic_allclocks = 1;
-#endif
-
 static uint32_t
 lvt_mode(struct lapic *la, u_int pin, uint32_t value)
 {
@@ -431,18 +421,21 @@
  * that it can drive hardclock, statclock, and profclock. 
  */
 enum lapic_clock
-lapic_setup_clock(void)
+lapic_setup_clock(enum lapic_clock srcsdes)
 {
 	u_long value;
 	int i;
 
+	/* lapic_setup_clock() should not be called with LAPIC_CLOCK_NONE. */
+	MPASS(srcsdes != LAPIC_CLOCK_NONE);
+
 	/* Can't drive the timer without a local APIC. */
-	if (lapic == NULL)
-		return (LAPIC_CLOCK_NONE);
+	if (lapic == NULL ||
+	    (resource_int_value("apic", 0, "clock", &i) == 0 && i == 0)) {
+		clockcoverage = LAPIC_CLOCK_NONE;
+		return (clockcoverage);
+	}
 
-	if (resource_int_value("apic", 0, "clock", &i) == 0 && i == 0)
-		return (LAPIC_CLOCK_NONE);
-
 	/* Start off with a divisor of 2 (power on reset default). */
 	lapic_timer_divisor = 2;
 
@@ -477,7 +470,7 @@
 	 * Please note that stathz and profhz are set only if all the
 	 * clocks are handled through the local APIC.
 	 */
-	if (lapic_allclocks != 0) {
+	if (srcsdes == LAPIC_CLOCK_ALL) {
 		if (hz >= 1500)
 			lapic_timer_hz = hz;
 		else if (hz >= 750)
@@ -487,7 +480,7 @@
 	} else
 		lapic_timer_hz = hz;
 	lapic_timer_period = value / lapic_timer_hz;
-	if (lapic_allclocks != 0) {
+	if (srcsdes == LAPIC_CLOCK_ALL) {
 		if (lapic_timer_hz < 128)
 			stathz = lapic_timer_hz;
 		else
@@ -501,7 +494,8 @@
 	 */
 	lapic_timer_periodic(lapic_timer_period);
 	lapic_timer_enable_intr();
-	return (lapic_allclocks == 0 ? LAPIC_CLOCK_HARDCLOCK : LAPIC_CLOCK_ALL);
+	clockcoverage = srcsdes;
+	return (srcsdes);
 }
 
 void
@@ -804,7 +798,7 @@
 		else
 			hardclock_cpu(TRAPF_USERMODE(frame));
 	}
-	if (lapic_allclocks != 0) {
+	if (clockcoverage == LAPIC_CLOCK_ALL) {
 
 		/* Fire statclock at stathz. */
 		la->la_stat_ticks += stathz;
Index: sys/amd64/include/apicvar.h
===================================================================
--- sys/amd64/include/apicvar.h	(revision 204308)
+++ sys/amd64/include/apicvar.h	(working copy)
@@ -230,7 +230,7 @@
 	    enum intr_trigger trigger);
 void	lapic_set_tpr(u_int vector);
 void	lapic_setup(int boot);
-enum lapic_clock	lapic_setup_clock(void);
+enum lapic_clock	lapic_setup_clock(enum lapic_clock srcsdes);
 
 #endif /* !LOCORE */
 #endif /* _MACHINE_APICVAR_H_ */
Index: sys/amd64/amd64/local_apic.c
===================================================================
--- sys/amd64/amd64/local_apic.c	(revision 204308)
+++ sys/amd64/amd64/local_apic.c	(working copy)
@@ -149,6 +149,7 @@
 volatile lapic_t *lapic;
 vm_paddr_t lapic_paddr;
 static u_long lapic_timer_divisor, lapic_timer_period, lapic_timer_hz;
+static enum lapic_clock clockcoverage;
 
 static void	lapic_enable(void);
 static void	lapic_resume(struct pic *pic);
@@ -160,9 +161,6 @@
 
 struct pic lapic_pic = { .pic_resume = lapic_resume };
 
-static int lapic_allclocks;
-TUNABLE_INT("machdep.lapic_allclocks", &lapic_allclocks);
-
 static uint32_t
 lvt_mode(struct lapic *la, u_int pin, uint32_t value)
 {
@@ -423,18 +421,21 @@
  * local APIC only for the hardclock and 0 if none of them can be handled.
  */
 enum lapic_clock
-lapic_setup_clock(void)
+lapic_setup_clock(enum lapic_clock srcsdes)
 {
 	u_long value;
 	int i;
 
+	/* lapic_setup_clock() should not be called with LAPIC_CLOCK_NONE. */
+	MPASS(srcsdes != LAPIC_CLOCK_NONE);
+
 	/* Can't drive the timer without a local APIC. */
-	if (lapic == NULL)
-		return (LAPIC_CLOCK_NONE);
+	if (lapic == NULL ||
+	    (resource_int_value("apic", 0, "clock", &i) == 0 && i == 0)) {
+		clockcoverage = LAPIC_CLOCK_NONE;
+		return (clockcoverage);
+	}
 
-	if (resource_int_value("apic", 0, "clock", &i) == 0 && i == 0)
-		return (LAPIC_CLOCK_NONE);
-
 	/* Start off with a divisor of 2 (power on reset default). */
 	lapic_timer_divisor = 2;
 
@@ -469,7 +470,7 @@
 	 * Please note that stathz and profhz are set only if all the
 	 * clocks are handled through the local APIC.
 	 */
-	if (lapic_allclocks != 0) {
+	if (srcsdes == LAPIC_CLOCK_ALL) {
 		if (hz >= 1500)
 			lapic_timer_hz = hz;
 		else if (hz >= 750)
@@ -479,7 +480,7 @@
 	} else
 		lapic_timer_hz = hz;
 	lapic_timer_period = value / lapic_timer_hz;
-	if (lapic_allclocks != 0) {
+	if (srcsdes == LAPIC_CLOCK_ALL) {
 		if (lapic_timer_hz < 128)
 			stathz = lapic_timer_hz;
 		else
@@ -493,7 +494,8 @@
 	 */
 	lapic_timer_periodic(lapic_timer_period);
 	lapic_timer_enable_intr();
-	return (lapic_allclocks == 0 ? LAPIC_CLOCK_HARDCLOCK : LAPIC_CLOCK_ALL);
+	clockcoverage = srcsdes;
+	return (srcsdes);
 }
 
 void
@@ -796,7 +798,7 @@
 		else
 			hardclock_cpu(TRAPF_USERMODE(frame));
 	}
-	if (lapic_allclocks != 0) {
+	if (clockcoverage == LAPIC_CLOCK_ALL) {
 
 		/* Fire statclock at stathz. */
 		la->la_stat_ticks += stathz;