Messages in this thread | | | Date | Fri, 29 Jun 2007 15:55:49 -0400 | From | "LOL ER" <> | Subject | Need help making sense of IRQ API |
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Hello, I've been trying to make sense of how the kernel (on an i386) calls __do_IRQ() from do_IRQ() for the past few days to no avail. After doing some research I found out that do_IRQ() calls the corresponding "highlevel irq-events handler", this lead me to believe that the kernel calls __do_IRQ through "desc->handle_irq(irq, desc);" (snippet from do_IRQ in arch/i386). Looking at the kernel I found a comment which reads, " * @handle_irq: highlevel irq-events handler [if NULL, __do_IRQ()]", instinctively I then grepped through the kernel to find any instances of where handle_IRQ is checked for being NULL. I then found an inlined function called generic_handle_irq that does just that. If indeed generic_handle_irq() is the default value of handle_irq(), why is its datatype not irq_flow_handler_t, and where in the kernel is it set as the default "highlevel irq-events handler?" Just to clarify what I mean, the handle_irq member in the irq_desc struct has its datatype as irq_flow_handler_t, which is a function pointer that takes 2 arguments, "unsigned int irq, struct irq_desc *desc", however unsigned generic_handle_irq() takes one argument, which is just an int representing the IRQ number. Thank You, Robert G. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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