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>
diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c
index 6fe1214..9d1f01e 100644
--- a/drivers/acpi/processor_idle.c
+++ b/drivers/acpi/processor_idle.c
@@ -581,6 +581,11 @@
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 @@
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 @@
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);