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clinuxkernelinterruptirq
montezuma
montezuma

Reputation: 61

Difference between request_irq and __interrupt

From what I read both are used to register interrupt handlers. I saw lots of request_irq calls in kernel code but not even one __interrupt call. Is __interrupt some way to register a handler from user space?

Upvotes: 6

Views: 5929

Answers (2)

Kumba
Kumba

Reputation: 2428

request_irq is essentially a wrapper call to request_threaded_irq, which allocates the IRQ resources and enables the IRQ. That's paraphrased from the comment block in kernel/irq/manage.c, Line #1239.

Basically, you want to use request_irq if you need to setup interrupt handling for a device of some kind. Make sure that whatever subsystem you are working in doesn't already provide a wrapper for request_irq, too. I.e., if you are working on a device driver, consider using the devm_* family of calls to auto-manage the minutiae, like freeing unused variables and such. See devm_request_threaded_irq at Line #29 in kernel/irq/devres.c for a better explanation. Its equivalent call (and the one you would most likely use) is devm_request_irq.

Upvotes: 8

Eduard Thamm
Eduard Thamm

Reputation: 942

As far as I remember __interrupt() is used to declare a function as ISR in userspace. I am not sure where I have this from but I'll come back to you as soon as I found the spot.

Upvotes: 0

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