> It is edge triggered so it won't refire when unmasked (especially if we don't know).
Well, we are smarter than that. soft-masking is a know well-solved
problem. We just latch that something happened while masked and refire
when unmasked. Not terribly hard. We already do that in various
situations to mask edge interrupts.
Masking in HW is totally optional. I don't mask in HW on cell for
example, the HW just can't.
We only re-fire if it actually occured while "masked", that should take
care that we never fire once too much, no ?
There must be some way of knowing what work is to do (ie, whether a DMA
q entry is completed, some kind of done bit, etc...). There generally is
at least, so that even in that case, spurrious MSIs are mostly a non
issue, but I don't think we have them here.
I still mostly dislike the new approach, I prefer Matthew's original one
with SW masking of the MSIs. For example, if you have the MSIs be 'one'
interrupt, then you hit all of the logic in the IRQ core to make sure
only one happens at once. Might not be what you want, and -will- cause
some to be dropped... not nice.
Ben.
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