diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index b52f47d..f223863 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1571,6 +1571,10 @@
 			Format: { parport<nr> | timid | 0 }
 			See also Documentation/parport.txt.
 
+	pmtmr=		[X86] Manual setup of pmtmr I/O Port. 
+			Override pmtimer IOPort with a hex value.
+			e.g. pmtmr=0x508
+
 	pnpacpi=	[ACPI]
 			{ off }
 
diff --git a/drivers/clocksource/acpi_pm.c b/drivers/clocksource/acpi_pm.c
index 7b46faf..bcd7d0e 100644
--- a/drivers/clocksource/acpi_pm.c
+++ b/drivers/clocksource/acpi_pm.c
@@ -215,3 +215,22 @@
  * but we still need to load before device_initcall
  */
 fs_initcall(init_acpi_pm_clocksource);
+
+/*
+ * Allow an override of the IOPort. Stupid BIOSes do not tell us about
+ * the PMTimer, but we might know where it is.
+ */
+static int __init parse_pmtmr(char *arg)
+{
+	unsigned long base;
+
+	if (strict_strtoul(arg, 16, &base))
+		return -EINVAL;
+
+	printk(KERN_INFO "PMTMR IOPort override: 0x%04x -> 0x%04x\n",
+	       (unsigned int)pmtmr_ioport, base);
+	pmtmr_ioport = base;
+
+	return 1;
+}
+__setup("pmtmr=", parse_pmtmr);
diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c
index ab80515..ffca825 100644
--- a/kernel/hrtimer.c
+++ b/kernel/hrtimer.c
@@ -300,11 +300,10 @@
  */
 u64 ktime_divns(const ktime_t kt, s64 div)
 {
-	u64 dclc, inc, dns;
+	u64 dclc;
 	int sft = 0;
 
-	dclc = dns = ktime_to_ns(kt);
-	inc = div;
+	dclc = ktime_to_ns(kt);
 	/* Make sure the divisor is less than 2^32: */
 	while (div >> 32) {
 		sft++;
@@ -632,8 +631,6 @@
  */
 void hres_timers_resume(void)
 {
-	WARN_ON_ONCE(num_online_cpus() > 1);
-
 	/* Retrigger the CPU local events: */
 	retrigger_next_event(NULL);
 }
diff --git a/kernel/posix-cpu-timers.c b/kernel/posix-cpu-timers.c
index f1525ad..c42a03a 100644
--- a/kernel/posix-cpu-timers.c
+++ b/kernel/posix-cpu-timers.c
@@ -1037,6 +1037,9 @@
 				sig->rlim[RLIMIT_RTTIME].rlim_cur +=
 								USEC_PER_SEC;
 			}
+			printk(KERN_INFO
+				"RT Watchdog Timeout: %s[%d]\n",
+				tsk->comm, task_pid_nr(tsk));
 			__group_send_sig_info(SIGXCPU, SEND_SIG_PRIV, tsk);
 		}
 	}
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index b854a89..86baa4f 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -48,6 +48,13 @@
 	unsigned long ticks = 0;
 	ktime_t delta;
 
+	/*
+	 * Do a quick check without holding xtime_lock:
+	 */
+	delta = ktime_sub(now, last_jiffies_update);
+	if (delta.tv64 < tick_period.tv64)
+		return;
+
 	/* Reevalute with xtime_lock held */
 	write_seqlock(&xtime_lock);
 
@@ -228,6 +235,7 @@
 			       local_softirq_pending());
 			ratelimit++;
 		}
+		goto end;
 	}
 
 	ts->idle_calls++;