ACPI: idle: mark_tsc_unstable() at init-time, not run-time

The c2 and c3 idle handlers check tsc_halts_in_c()
after every time they return from idle.  Um, when?:-)

Move this check to init-time to remove the unnecessary
run-time overhead, and also to have the check complete before
the first entry into the idle handler.

ff69f2bba67bd45514923aaedbf40fe351787c59
(acpi: fix of pmtimer overflow that make Cx states time incorrect)
replaced the hard-coded use of the PM-timer inside idle,
with ktime_get_readl(), which possibly uses the TSC --
so it is now especially prudent to detect a broken TSC
before entering idle.

http://bugzilla.kernel.org/show_bug.cgi?id=13087

Signed-off-by: Len Brown <len.brown@intel.com>

1 files changed, 5 insertions, 10 deletions

diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c
index 6fe121434ff..9d1f01ee65d 100644
--- a/drivers/acpi/processor_idle.c
+++ b/drivers/acpi/processor_idle.c
@@ -581,6 +581,11 @@ static int acpi_processor_power_verify(struct acpi_processor *pr)
         for (i = 1; i < ACPI_PROCESSOR_MAX_POWER; i++) {
                 struct acpi_processor_cx *cx = &pr->power.states[i];
 
+#if defined (CONFIG_GENERIC_TIME) && defined (CONFIG_X86)
+                /* TSC could halt in idle, so notify users */
+                if (tsc_halts_in_c(cx->type))
+                        mark_tsc_unstable("TSC halts in idle");;
+#endif
                 switch (cx->type) {
                 case ACPI_STATE_C1:
                         cx->valid = 1;
@@ -871,11 +876,6 @@ static int acpi_idle_enter_simple(struct cpuidle_device *dev,
         kt2 = ktime_get_real();
         idle_time =  ktime_to_us(ktime_sub(kt2, kt1));
 
-#if defined (CONFIG_GENERIC_TIME) && defined (CONFIG_X86)
-        /* TSC could halt in idle, so notify users */
-        if (tsc_halts_in_c(cx->type))
-                mark_tsc_unstable("TSC halts in idle");;
-#endif
         sleep_ticks = us_to_pm_timer_ticks(idle_time);
 
         /* Tell the scheduler how much we idled: */
@@ -989,11 +989,6 @@ static int acpi_idle_enter_bm(struct cpuidle_device *dev,
                 spin_unlock(&c3_lock);
         }
 
-#if defined (CONFIG_GENERIC_TIME) && defined (CONFIG_X86)
-        /* TSC could halt in idle, so notify users */
-        if (tsc_halts_in_c(ACPI_STATE_C3))
-                mark_tsc_unstable("TSC halts in idle");
-#endif
         sleep_ticks = us_to_pm_timer_ticks(idle_time);
         /* Tell the scheduler how much we idled: */
         sched_clock_idle_wakeup_event(sleep_ticks*PM_TIMER_TICK_NS);