Bamboo PCI interrupt issues

Benjamin Herrenschmidt benh at kernel.crashing.org
Wed Mar 5 08:01:30 EST 2008


On Tue, 2008-03-04 at 21:59 +0100, Segher Boessenkool wrote:
> >> More generally, the target interrupt descriptors (sense values, in
> >> particular) in a device tree interrupt map describe the interrupts as
> >> seen on the target interrupt controller, *not* as seen on this 
> >> (source)
> >> interrupt domain.  This should be obvious, but since the source
> >> interrupt
> >> descriptor for PCI doesn't have a sense value (it's always level low,
> >> after all), it can be confusing.  Well, interrupts always are 
> >> confusing
> >> :-)
> >
> > Sure. But if your stupid bridge sticks a not gate between the PIRQ 
> > input
> > and the UIC (interrupt controller), effectively, the UIC sees a 
> > reversed
> > polarity. Thus you need to put in your interrupt map a reversed 
> > polarity
> > information for the UIC interrupt specifiers.
> 
> That's what I said, isn't it?  :-)

Maybe, I wasn't sure I decrypted you properly :-)

Ben.





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