[LinuxBIOS] IRQ question

bari bari at onelabs.com
Sat Nov 17 16:40:08 CET 2007

FengLibo wrote:

> A simple question: when talking about IRQ, you mean one of the 256 interrupt vectors within x86, or one of the pins of APIC, or one of the pins of 8259? I always got confused by it.

Yes! I see the same term "IRQ" used for both hardware and software
interrupts all the time. Context is the only key at times as to which
interrupt the writer is referring to.

Software Interrupt =  256 interrupt vectors within x86
Hardware Interrupt = "IRQ" signals on APIC, 8259 or other hardware
interrupt controller


> Another questiong about IRQ: The interrupt line register in PCI 
> configurationn space also contains an IRQ number, for example, my 
> ethernet card is IRQ 10, the IRQ number is the interrupter vector in x86 
> or the physical signal in APIC or PIC?

PCI Hardware Interrupt



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