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SubjectRe: [PATCH 3/3] clocksource: atmel-pit: Remove irq handler when clock event is unused
On Fri, 17 Jul 2015, Alexandre Belloni wrote:
> /*
> + * IRQ handler for the timer.
> + */
> +static irqreturn_t at91sam926x_pit_interrupt(int irq, void *dev_id)
> +{
> + struct pit_data *data = dev_id;
> +
> + /*
> + * irqs should be disabled here, but as the irq is shared they are only
> + * guaranteed to be off if the timer irq is registered first.

That's wrong. We run all handlers with interrupts disabled for about 5
years now.

> + */
> + WARN_ON_ONCE(!irqs_disabled());


> + /* The PIT interrupt may be disabled, and is shared */
> + if (clockevent_state_periodic(&data->clkevt) &&
> + (pit_read(data->base, AT91_PIT_SR) & AT91_PIT_PITS)) {
> + unsigned nr_ticks;
> +
> + /* Get number of ticks performed before irq, and ack it */
> + nr_ticks = PIT_PICNT(pit_read(data->base, AT91_PIT_PIVR));
> + do {
> + data->cnt += data->cycle;
> + data->clkevt.event_handler(&data->clkevt);
> + nr_ticks--;
> + } while (nr_ticks);

I don't think you need this loop. You have a proper clocksource
registered so the timekeeping code will handle the lost ticks nicely.


Thanks,

tglx


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