Messages in this thread |  | | Date | Mon, 12 Feb 2007 09:35:49 +0000 | From | Russell King <> | Subject | Re: genirq: Add a set_irq_handler_locked() function |
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On Mon, Feb 12, 2007 at 02:17:28PM +1100, David Gibson wrote: > On Fri, Feb 09, 2007 at 07:36:40AM +0000, Russell King wrote: > > On Fri, Feb 09, 2007 at 02:48:42PM +1100, David Gibson wrote: > > > At present set_irq_handler() and all the existing variants take the > > > desc->lock for the irq in question before adjusting the irq's flow > > > handler. This can cause problems for irq chips for which a given > > > interrupt can be either level or edge depending on what's attached. > > > > Are you sure you need to change the flow handler depending on how > > you program the device? > > > > Since the outset of this design, I've had what are essentially edge > > based interrupt sources using the "level" handlers because they haven't > > had a "broken" edge implementation. By that, I mean that the masking > > is done in such a way that you miss edges when the source is masked. > > > > If you do not miss edges while the source is masked, there's no point > > in having the complexity of the "edge" based handler in the path - it > > buys you nothing. Just use the "level" handler instead. > > I see... how terribly obvious.
Do you have a better way of naming the functions?
> As far as I know, the 4xx UIC does things correctly, though I don't > have handy any devices with edge interrupts to test it with. > > It would still be nice to have this change, so we can use the > lazy-masking from handle_edge_irq(), but I guess I can do without it > for now.
If you have correct behaviour from your interrupt controller for edge based interrupts, you don't need the lazy masking, so why make things complicated in this way?
-- Russell King Linux kernel 2.6 ARM Linux - http://www.arm.linux.org.uk/ maintainer of: - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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