diff --git a/arch/ia64/include/asm/acpi.h b/arch/ia64/include/asm/acpi.h
index 97cb16086314..2e73dffa16af 100644
--- a/arch/ia64/include/asm/acpi.h
+++ b/arch/ia64/include/asm/acpi.h
@@ -85,6 +85,7 @@ ia64_acpi_release_global_lock (unsigned int *lock)
 	((Acq) = ia64_acpi_release_global_lock(&facs->global_lock))
 
 #ifdef	CONFIG_ACPI
+extern int acpi_lapic;
 #define acpi_disabled 0	/* ACPI always enabled on IA64 */
 #define acpi_noirq 0	/* ACPI always enabled on IA64 */
 #define acpi_pci_disabled 0 /* ACPI PCI always enabled on IA64 */
diff --git a/arch/ia64/kernel/acpi.c b/arch/ia64/kernel/acpi.c
index 0d407b300762..615ef81def49 100644
--- a/arch/ia64/kernel/acpi.c
+++ b/arch/ia64/kernel/acpi.c
@@ -56,6 +56,7 @@
 
 #define PREFIX			"ACPI: "
 
+int acpi_lapic;
 unsigned int acpi_cpei_override;
 unsigned int acpi_cpei_phys_cpuid;
 
@@ -676,6 +677,8 @@ int __init early_acpi_boot_init(void)
 	if (ret < 1)
 		printk(KERN_ERR PREFIX
 		       "Error parsing MADT - no LAPIC entries\n");
+	else
+		acpi_lapic = 1;
 
 #ifdef CONFIG_SMP
 	if (available_cpus == 0) {
diff --git a/drivers/acpi/acpi_pad.c b/drivers/acpi/acpi_pad.c
index 37d73024b82e..f148a0580e04 100644
--- a/drivers/acpi/acpi_pad.c
+++ b/drivers/acpi/acpi_pad.c
@@ -156,12 +156,13 @@ static int power_saving_thread(void *data)
 
 	while (!kthread_should_stop()) {
 		int cpu;
-		u64 expire_time;
+		unsigned long expire_time;
 
 		try_to_freeze();
 
 		/* round robin to cpus */
-		if (last_jiffies + round_robin_time * HZ < jiffies) {
+		expire_time = last_jiffies + round_robin_time * HZ;
+		if (time_before(expire_time, jiffies)) {
 			last_jiffies = jiffies;
 			round_robin_cpu(tsk_index);
 		}
@@ -200,7 +201,7 @@ static int power_saving_thread(void *data)
 					CLOCK_EVT_NOTIFY_BROADCAST_EXIT, &cpu);
 			local_irq_enable();
 
-			if (jiffies > expire_time) {
+			if (time_before(expire_time, jiffies)) {
 				do_sleep = 1;
 				break;
 			}
@@ -215,8 +216,15 @@ static int power_saving_thread(void *data)
 		 * borrow CPU time from this CPU and cause RT task use > 95%
 		 * CPU time. To make 'avoid starvation' work, takes a nap here.
 		 */
-		if (do_sleep)
+		if (unlikely(do_sleep))
 			schedule_timeout_killable(HZ * idle_pct / 100);
+
+		/* If an external event has set the need_resched flag, then
+		 * we need to deal with it, or this loop will continue to
+		 * spin without calling __mwait().
+		 */
+		if (unlikely(need_resched()))
+			schedule();
 	}
 
 	exit_round_robin(tsk_index);
diff --git a/drivers/acpi/acpi_processor.c b/drivers/acpi/acpi_processor.c
index 52c81c49cc7d..1c085742644f 100644
--- a/drivers/acpi/acpi_processor.c
+++ b/drivers/acpi/acpi_processor.c
@@ -268,7 +268,7 @@ static int acpi_processor_get_info(struct acpi_device *device)
 	pr->apic_id = apic_id;
 
 	cpu_index = acpi_map_cpuid(pr->apic_id, pr->acpi_id);
-	if (!cpu0_initialized) {
+	if (!cpu0_initialized && !acpi_lapic) {
 		cpu0_initialized = 1;
 		/* Handle UP system running SMP kernel, with no LAPIC in MADT */
 		if ((cpu_index == -1) && (num_online_cpus() == 1))
diff --git a/drivers/acpi/processor_driver.c b/drivers/acpi/processor_driver.c
index 7f70f3182d50..4fcbd670415c 100644
--- a/drivers/acpi/processor_driver.c
+++ b/drivers/acpi/processor_driver.c
@@ -121,6 +121,13 @@ static int acpi_cpu_soft_notify(struct notifier_block *nfb,
 	struct acpi_processor *pr = per_cpu(processors, cpu);
 	struct acpi_device *device;
 
+	/*
+	 * CPU_STARTING and CPU_DYING must not sleep. Return here since
+	 * acpi_bus_get_device() may sleep.
+	 */
+	if (action == CPU_STARTING || action == CPU_DYING)
+		return NOTIFY_DONE;
+
 	if (!pr || acpi_bus_get_device(pr->handle, &device))
 		return NOTIFY_DONE;