diff options
Diffstat (limited to 'arch/x86/kernel/i8253.c')
| -rw-r--r-- | arch/x86/kernel/i8253.c | 10 |
1 files changed, 9 insertions, 1 deletions
diff --git a/arch/x86/kernel/i8253.c b/arch/x86/kernel/i8253.c index a42c8074532..0f8f35458a8 100644 --- a/arch/x86/kernel/i8253.c +++ b/arch/x86/kernel/i8253.c @@ -197,7 +197,15 @@ static struct clocksource clocksource_pit = { static int __init init_pit_clocksource(void) { - if (num_possible_cpus() > 1) /* PIT does not scale! */ + /* + * Several reasons not to register PIT as a clocksource: + * + * - On SMP PIT does not scale due to i8253_lock + * - when HPET is enabled + * - when local APIC timer is active (PIT is switched off) + */ + if (num_possible_cpus() > 1 || is_hpet_enabled() || + pit_clockevent.mode != CLOCK_EVT_MODE_PERIODIC) return 0; clocksource_pit.mult = clocksource_hz2mult(CLOCK_TICK_RATE, 20); |