diff options
Diffstat (limited to 'arch/x86')
| -rw-r--r-- | arch/x86/kernel/apic.c | 47 |
1 files changed, 30 insertions, 17 deletions
diff --git a/arch/x86/kernel/apic.c b/arch/x86/kernel/apic.c index 4b6df2469fe..7bcd746d704 100644 --- a/arch/x86/kernel/apic.c +++ b/arch/x86/kernel/apic.c @@ -535,7 +535,8 @@ static void __init lapic_cal_handler(struct clock_event_device *dev) } } -static int __init calibrate_by_pmtimer(long deltapm, long *delta) +static int __init +calibrate_by_pmtimer(long deltapm, long *delta, long *deltatsc) { const long pm_100ms = PMTMR_TICKS_PER_SEC / 10; const long pm_thresh = pm_100ms / 100; @@ -557,18 +558,29 @@ static int __init calibrate_by_pmtimer(long deltapm, long *delta) if (deltapm > (pm_100ms - pm_thresh) && deltapm < (pm_100ms + pm_thresh)) { apic_printk(APIC_VERBOSE, "... PM timer result ok\n"); - } else { - res = (((u64)deltapm) * mult) >> 22; - do_div(res, 1000000); - pr_warning("APIC calibration not consistent " - "with PM Timer: %ldms instead of 100ms\n", - (long)res); - /* Correct the lapic counter value */ - res = (((u64)(*delta)) * pm_100ms); + return 0; + } + + res = (((u64)deltapm) * mult) >> 22; + do_div(res, 1000000); + pr_warning("APIC calibration not consistent " + "with PM Timer: %ldms instead of 100ms\n",(long)res); + + /* Correct the lapic counter value */ + res = (((u64)(*delta)) * pm_100ms); + do_div(res, deltapm); + pr_info("APIC delta adjusted to PM-Timer: " + "%lu (%ld)\n", (unsigned long)res, *delta); + *delta = (long)res; + + /* Correct the tsc counter value */ + if (cpu_has_tsc) { + res = (((u64)(*deltatsc)) * pm_100ms); do_div(res, deltapm); - pr_info("APIC delta adjusted to PM-Timer: " - "%lu (%ld)\n", (unsigned long)res, *delta); - *delta = (long)res; + apic_printk(APIC_VERBOSE, "TSC delta adjusted to " + "PM-Timer: %lu (%ld) \n", + (unsigned long)res, *deltatsc); + *deltatsc = (long)res; } return 0; @@ -579,7 +591,7 @@ static int __init calibrate_APIC_clock(void) struct clock_event_device *levt = &__get_cpu_var(lapic_events); void (*real_handler)(struct clock_event_device *dev); unsigned long deltaj; - long delta; + long delta, deltatsc; int pm_referenced = 0; local_irq_disable(); @@ -609,9 +621,11 @@ static int __init calibrate_APIC_clock(void) delta = lapic_cal_t1 - lapic_cal_t2; apic_printk(APIC_VERBOSE, "... lapic delta = %ld\n", delta); + deltatsc = (long)(lapic_cal_tsc2 - lapic_cal_tsc1); + /* we trust the PM based calibration if possible */ pm_referenced = !calibrate_by_pmtimer(lapic_cal_pm2 - lapic_cal_pm1, - &delta); + &delta, &deltatsc); /* Calculate the scaled math multiplication factor */ lapic_clockevent.mult = div_sc(delta, TICK_NSEC * LAPIC_CAL_LOOPS, @@ -629,11 +643,10 @@ static int __init calibrate_APIC_clock(void) calibration_result); if (cpu_has_tsc) { - delta = (long)(lapic_cal_tsc2 - lapic_cal_tsc1); apic_printk(APIC_VERBOSE, "..... CPU clock speed is " "%ld.%04ld MHz.\n", - (delta / LAPIC_CAL_LOOPS) / (1000000 / HZ), - (delta / LAPIC_CAL_LOOPS) % (1000000 / HZ)); + (deltatsc / LAPIC_CAL_LOOPS) / (1000000 / HZ), + (deltatsc / LAPIC_CAL_LOOPS) % (1000000 / HZ)); } apic_printk(APIC_VERBOSE, "..... host bus clock speed is " |