Shared IRQ lines

[gaf]

Hello,
is there any way of telling which device caused an shared IRQ or does this have to be determined by the drivers themselves ?

regards,
gaf

[distantvoices]

I think this has to be determined by the drivers. There are some flags/functions in the pci config space which can be used to determine inside the interrupt handler: Have you triggered this irq? if no? next interrupt handler please. Untl, if no handler feels responsible, a global handler is called to report about the facht that some hardware has demanded attention.

In short, you build a linked list of handlers and have one after the other check the device - if it is responsible for the device, it should take the needed operations.

hm. Me is still at research concerning chained interrupt handlers and shared irq lines. so thats ust my rambling.

[gaf]

Thanks for your help, beyond infinity. I think that it's a pretty bad hardware design if there's no standard way of detecting which device caused an IRQ, but that's just one of the idiocies of the x86 and I can't change it...

In short, you build a linked list of handlers and have one after the other check the device - if it is responsible for the device, it should take the needed operations.

I'd use a tree . That way it's easier to keep track of the access rights: only an app/driver that already owns an IRQ can give it to (or share it with) another task.

regards,
gaf