Bamboo PCI interrupt issues

Segher Boessenkool segher at kernel.crashing.org
Wed Mar 5 07:59:28 EST 2008


>> 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?  :-)


Segher




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