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Diffstat (limited to 'arch/i386/kernel/apic.c')
-rw-r--r--arch/i386/kernel/apic.c78
1 files changed, 27 insertions, 51 deletions
diff --git a/arch/i386/kernel/apic.c b/arch/i386/kernel/apic.c
index 2383bcf18c5..5cff7970911 100644
--- a/arch/i386/kernel/apic.c
+++ b/arch/i386/kernel/apic.c
@@ -338,6 +338,7 @@ void __init setup_boot_APIC_clock(void)
void (*real_handler)(struct clock_event_device *dev);
unsigned long deltaj;
long delta, deltapm;
+ int pm_referenced = 0;
apic_printk(APIC_VERBOSE, "Using local APIC timer interrupts.\n"
"calibrating APIC timer ...\n");
@@ -357,7 +358,8 @@ void __init setup_boot_APIC_clock(void)
/* Let the interrupts run */
local_irq_enable();
- while(lapic_cal_loops <= LAPIC_CAL_LOOPS);
+ while (lapic_cal_loops <= LAPIC_CAL_LOOPS)
+ cpu_relax();
local_irq_disable();
@@ -394,6 +396,7 @@ void __init setup_boot_APIC_clock(void)
"%lu (%ld)\n", (unsigned long) res, delta);
delta = (long) res;
}
+ pm_referenced = 1;
}
/* Calculate the scaled math multiplication factor */
@@ -423,68 +426,41 @@ void __init setup_boot_APIC_clock(void)
calibration_result / (1000000 / HZ),
calibration_result % (1000000 / HZ));
-
- apic_printk(APIC_VERBOSE, "... verify APIC timer\n");
-
- /*
- * Setup the apic timer manually
- */
local_apic_timer_verify_ok = 1;
- levt->event_handler = lapic_cal_handler;
- lapic_timer_setup(CLOCK_EVT_MODE_PERIODIC, levt);
- lapic_cal_loops = -1;
- /* Let the interrupts run */
- local_irq_enable();
+ /* We trust the pm timer based calibration */
+ if (!pm_referenced) {
+ apic_printk(APIC_VERBOSE, "... verify APIC timer\n");
- while(lapic_cal_loops <= LAPIC_CAL_LOOPS);
+ /*
+ * Setup the apic timer manually
+ */
+ levt->event_handler = lapic_cal_handler;
+ lapic_timer_setup(CLOCK_EVT_MODE_PERIODIC, levt);
+ lapic_cal_loops = -1;
- local_irq_disable();
+ /* Let the interrupts run */
+ local_irq_enable();
- /* Stop the lapic timer */
- lapic_timer_setup(CLOCK_EVT_MODE_SHUTDOWN, levt);
+ while(lapic_cal_loops <= LAPIC_CAL_LOOPS)
+ cpu_relax();
- local_irq_enable();
+ local_irq_disable();
- /* Jiffies delta */
- deltaj = lapic_cal_j2 - lapic_cal_j1;
- apic_printk(APIC_VERBOSE, "... jiffies delta = %lu\n", deltaj);
+ /* Stop the lapic timer */
+ lapic_timer_setup(CLOCK_EVT_MODE_SHUTDOWN, levt);
- /* Check, if the PM timer is available */
- deltapm = lapic_cal_pm2 - lapic_cal_pm1;
- apic_printk(APIC_VERBOSE, "... PM timer delta = %ld\n", deltapm);
+ local_irq_enable();
- local_apic_timer_verify_ok = 0;
+ /* Jiffies delta */
+ deltaj = lapic_cal_j2 - lapic_cal_j1;
+ apic_printk(APIC_VERBOSE, "... jiffies delta = %lu\n", deltaj);
- if (deltapm) {
- if (deltapm > (pm_100ms - pm_thresh) &&
- deltapm < (pm_100ms + pm_thresh)) {
- apic_printk(APIC_VERBOSE, "... PM timer result ok\n");
- /* Check, if the jiffies result is consistent */
- if (deltaj < LAPIC_CAL_LOOPS-2 ||
- deltaj > LAPIC_CAL_LOOPS+2) {
- /*
- * Not sure, what we can do about this one.
- * When high resultion timers are active
- * and the lapic timer does not stop in C3
- * we are fine. Otherwise more trouble might
- * be waiting. -- tglx
- */
- printk(KERN_WARNING "Global event device %s "
- "has wrong frequency "
- "(%lu ticks instead of %d)\n",
- global_clock_event->name, deltaj,
- LAPIC_CAL_LOOPS);
- }
- local_apic_timer_verify_ok = 1;
- }
- } else {
/* Check, if the jiffies result is consistent */
- if (deltaj >= LAPIC_CAL_LOOPS-2 &&
- deltaj <= LAPIC_CAL_LOOPS+2) {
+ if (deltaj >= LAPIC_CAL_LOOPS-2 && deltaj <= LAPIC_CAL_LOOPS+2)
apic_printk(APIC_VERBOSE, "... jiffies result ok\n");
- local_apic_timer_verify_ok = 1;
- }
+ else
+ local_apic_timer_verify_ok = 0;
}
if (!local_apic_timer_verify_ok) {