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

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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.

ff69f2bba6
(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>
This commit is contained in:
Len Brown 2009-04-21 00:50:11 -04:00
parent 0910697403
commit a71e4917dc
1 changed files with 5 additions and 10 deletions
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15
drivers/acpi/processor_idle.c
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@ -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);