PCI <-> ISA interrupt sharing

Ulrich Windl (Ulrich.Windl@rz.uni-regensburg.de)
Thu, 2 May 1996 08:55:20 +0200

>From my knowledge PCI interrupts are usually negative level triggered
while ISA interrupts are usually positive edge triggered. Thus I
suspect that you can't share interrupts between PCI and ISA.

But currently the kernel does not take any advantage of this fact. I
wonder if the probing for interrupts during autodetection can be
optimized (we are talking about ISA-only cards).

I aslo wonder if all the memory regions of detected PCI cards should
be registered, even if no driver is loaded. Can one assume that no
PCI card will generate an interrupt if the corresponding driver is
not loaded? If no, shouldn't the PCI interrupts be registererd as
well during startup?

(I don't know too much about PCI yet)
Ulrich Windl