Messages in this thread | | | Date | Wed, 22 Jun 2011 23:32:03 +0200 (CEST) | From | Thomas Gleixner <> | Subject | Re: Simulating level triggered interrupts with edges |
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On Wed, 22 Jun 2011, Mark Brown wrote:
> 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
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