x86: C1E late detection fix. Really switch off lapic timer

Doh, I completely missed that devices marked DUMMY are not running
the set_mode function. So we force broadcasting, but we keep the
local APIC timer running.

Let the clock event layer mark the device _after_ switching it off.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

arch/x86/kernel/apic_64.c

@@ -974,15 +974,12 @@ void __init setup_boot_APIC_clock (void)
  */
 void __cpuinit check_boot_apic_timer_broadcast(void)
 {
-	struct clock_event_device *levt = &per_cpu(lapic_events, boot_cpu_id);
-
 	if (!disable_apic_timer ||
 	    (lapic_clockevent.features & CLOCK_EVT_FEAT_DUMMY))
 		return;
 
 	printk(KERN_INFO "AMD C1E detected late. Force timer broadcast.\n");
 	lapic_clockevent.features |= CLOCK_EVT_FEAT_DUMMY;
-	levt->features |= CLOCK_EVT_FEAT_DUMMY;
 
 	local_irq_enable();
 	clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_FORCE, &boot_cpu_id);

kernel/time/tick-broadcast.c

@@ -222,20 +222,8 @@ static void tick_do_broadcast_on_off(void *why)
 	if (!dev || !(dev->features & CLOCK_EVT_FEAT_C3STOP))
 		goto out;
 
-	/*
-	 * Defect device ?
-	 */
-	if (!tick_device_is_functional(dev)) {
-		/*
-		 * AMD C1E wreckage fixup:
-		 *
-		 * Device was registered functional in the first
-		 * place. Now the secondary CPU detected the C1E
-		 * misfeature and notifies us to fix it up
-		 */
-		if (*reason != CLOCK_EVT_NOTIFY_BROADCAST_FORCE)
+	if (!tick_device_is_functional(dev))
 		goto out;
-	}
 
 	switch (*reason) {
 	case CLOCK_EVT_NOTIFY_BROADCAST_ON:
@@ -246,6 +234,8 @@ static void tick_do_broadcast_on_off(void *why)
 				clockevents_set_mode(dev,
 						     CLOCK_EVT_MODE_SHUTDOWN);
 		}
+		if (*reason == CLOCK_EVT_NOTIFY_BROADCAST_FORCE)
+			dev->features |= CLOCK_EVT_FEAT_DUMMY;
 		break;
 	case CLOCK_EVT_NOTIFY_BROADCAST_OFF:
 		if (cpu_isset(cpu, tick_broadcast_mask)) {