Hi,

Pawel Laszczak [off-list ref] writes:

quoted

quoted

quoted

quoted

IRQF_ONESHOT can be used  only in threaded handled.
"
 * IRQF_ONESHOT - Interrupt is not reenabled after the hardirq handler finished.
 *                Used by threaded interrupts which need to keep the
 *                irq line disabled until the threaded handler has been run.
"

so?

I don't understand why If I don't have threaded handler why I need IRQF_ONESHOT.
Why interrupt cannot be reenabled after hardirq handler finished ?
I do not use threaded handler so this flag seem unnecessary.

Unless this has changed over the years, it was a requirement from IRQ susbystem.

/*
 * Drivers are often written to work w/o knowledge about the
 * underlying irq chip implementation, so a request for a
 * threaded irq without a primary hard irq context handler
 * requires the ONESHOT flag to be set. Some irq chips like
 * MSI based interrupts are per se one shot safe. Check the
 * chip flags, so we can avoid the unmask dance at the end of
 * the threaded handler for those.
 */
if (desc->irq_data.chip->flags & IRQCHIP_ONESHOT_SAFE)
	new->flags &= ~IRQF_ONESHOT;

From description I understand that it should be set when driver uses only 
threaded handler without hard irq handler.
eg. 

	ret = devm_request_threaded_irq(dev, data->usb_id_irq,
					NULL, int3496_thread_isr,
					IRQF_SHARED | IRQF_ONESHOT |
					IRQF_TRIGGER_RISING |
					IRQF_TRIGGER_FALLING,
					dev_name(dev), data);

It make sense, we don't have hard irq handler so we can't clear source of interrupt. 
If we clear it immediately in interrupt controller then the same interrupt could 
be raised again, because it was not cleared e.g in controller register. 

You are correct. Big mistake on my side. Apologies.

-- 
balbi