Don't need to read PIT in timer handler when PM timer is used The PM timer path through main_timer_handler doesn't need the delay variable because it figures it out in a different way. Don't try to read it from the PIT. With stopped PIT timer it is even useless. Signed-off-by: Andi Kleen arch/x86_64/kernel/time.c | 4 ++-- 1 files changed, 2 insertions(+), 2 deletions(-) Index: linux/arch/x86_64/kernel/time.c =================================================================== --- linux.orig/arch/x86_64/kernel/time.c +++ linux/arch/x86_64/kernel/time.c @@ -349,7 +349,7 @@ void main_timer_handler(struct pt_regs * { static unsigned long rtc_update = 0; unsigned long tsc; - int delay, offset = 0, lost = 0; + int delay = 0, offset = 0, lost = 0; /* * Here we are in the timer irq handler. We have irqs locally disabled (so we @@ -370,7 +370,7 @@ void main_timer_handler(struct pt_regs * */ offset = hpet_readl(HPET_T0_CMP) - hpet_tick; delay = hpet_readl(HPET_COUNTER) - offset; - } else { + } else if (!pmtmr_ioport) { spin_lock(&i8253_lock); outb_p(0x00, 0x43); delay = inb_p(0x40);