On Tue, 26 Aug 2014 08:33:18 +0200, Oscar Salvador said: > If I get the IRQ from the pci_dev, I get a X, but if I get the IRQ > from the config space, I get another different number Y. > > Would be you so kind to explain: > > 1- Why it's better use the values stored in pci_dev structure instead > of read from config space. > 2- Why the IRQ number is different? (Maybe this question is answered > with the first question hehe) The Linux kernel keeps track of both physical and logical IRQ numbers. So physical IRQ 0 is often wired to a timer on x86 systems, but logical IRQ 0 is used for NO_IRQ in dev->irq type usages. Screw it, I'll let Linus explain from a decade ago: http://yarchive.net/comp/linux/no_irq.html
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