Difference btw interrupt and interrupt request

Question

I am learning kernel interrupt handling and have question about probe_irq_on explanation http://www.linuxcertif.com/man/9/probe_irq_on/en/

"turns on IRQ detection. It operates by enabling all interrupts which have no handlers, while keeping the handlers for those interrupts NULL. The kernel's generic interrupt handling routine will disable these IRQs when an interrupt is received on them."

Does it say "interrupt is received on these IRQs" I always thought IRQ(Interrupt request) is same as Interrupt.So quite confused about this. Is there any difference btw these two ??

Thanks

Answer 1

An interrupt request is just an indication to the CPU that a specific interrupt wants to happen. But perhaps interrupts are temporarily disabled, or another higher-priority interrupt is already going on.

Thus the interrupt itself doesn't happen until that request is serviced.

Here's some more reading for you about interrupt handlers.

Answer 2

The interrupt is the actual event that happens on the IRQ.