Simulating level triggered interrupts with edges

I've run into a couple of cases recently where a system has had a device with a level triggered interrupt connected to an edge triggered interrupt controller. Ignoring for the minute the hardware design concerns one might have this strikes me as something I'd expect the kernel to take a reasonable stab at handling in common code since it should be possible to have the core simply call the level triggered handler repeatedly until it returns IRQ_NONE when used with an edge based interrupt. Obviously this leaves something to be desired but something like this seems to be the most sensible way to deal with such systems.

Is this supported by the current code? I can't see any such support but that doesn't mean I'm not missing it. If it is not supported and I'm not missing some much bigger problem with the idea can you make any suggestions about the least bad way to allow systems to do this?

No, we don't have support for this. Drivers should be careful about such issues, but yes I can understand that we should think about having support in the core code for such HW crap instead of cluttering the drivers with such issues.

Though it's non-trivial. Think threaded interrupts, where we cannot deal with that in handle_irq_edge(). I have no immediate idea how to solve that at the core code, but feel free to have a stab.

Thanks,

tglx

Yes, that's why I asked - all the devices I care about have threaded handlers and I care about a system where the interrupt controller is threaded too. I was thinking error handling on set_type() and flags but thought I must be missing something. I'll probably have a poke sometime anyway.