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Commit a71e4917 authored by Len Brown's avatar Len Brown
Browse files

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.

ff69f2bb
(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: default avatarLen Brown <len.brown@intel.com>
parent 09106974

drivers/acpi/processor_idle.c

+5 −10
Original line number Original line Diff line number Diff line
@@ -581,6 +581,11 @@ static int acpi_processor_power_verify(struct acpi_processor *pr) 
	for (i = 1; i < ACPI_PROCESSOR_MAX_POWER; i++) {

	for (i = 1; i < ACPI_PROCESSOR_MAX_POWER; i++) {

		struct acpi_processor_cx *cx = &pr->power.states[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) {

		switch (cx->type) {

		case ACPI_STATE_C1:

		case ACPI_STATE_C1:

			cx->valid = 1;

			cx->valid = 1;
@@ -871,11 +876,6 @@ static int acpi_idle_enter_simple(struct cpuidle_device *dev, 
	kt2 = ktime_get_real();

	kt2 = ktime_get_real();

	idle_time =  ktime_to_us(ktime_sub(kt2, kt1));

	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);

	sleep_ticks = us_to_pm_timer_ticks(idle_time);





	/* Tell the scheduler how much we idled: */

	/* 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);

		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);

	sleep_ticks = us_to_pm_timer_ticks(idle_time);

	/* Tell the scheduler how much we idled: */

	/* Tell the scheduler how much we idled: */

	sched_clock_idle_wakeup_event(sleep_ticks*PM_TIMER_TICK_NS);

	sched_clock_idle_wakeup_event(sleep_ticks*PM_TIMER_TICK_NS);