On Thu, Jul 26, 2007 at 09:54:50AM -0400, Dmitry Torokhov wrote: > Hi, > > On 7/26/07, Fernando Luis Vázquez Cao <[EMAIL PROTECTED]> wrote: > >I made an interesting finding while testing the two patches below. > > > >http://lkml.org/lkml/2007/7/19/685 > >http://lkml.org/lkml/2007/7/19/687 > > > >These patches modify the traditional CONFIG_DEBUG_KERNEL in such a way > >that the request_irq prints a warning if after calling the handler it > >returned IRQ_HANDLED . > > > >The code looks like this: > > > >int request_irq(unsigned int irq, irq_handler_t handler, > > unsigned long irqflags, const char *devname, void > >*dev_id) > >..... > > if (irqflags & IRQF_DISABLED) { > > unsigned long flags; > > > > local_irq_save(flags); > > retval = handler(irq, dev_id); > > local_irq_restore(flags); > > } else > > retval = handler(irq, dev_id); > > if (retval == IRQ_HANDLED) { > > printk(KERN_WARNING > > "%s (IRQ %d) handled a spurious interrupt\n", > > devname, irq); > > } > >..... > > > >I discovered that i8042_aux_test_irq handles the "fake" interrupt, > >which, in principle, is not correct because it obviously isn't a real > >interrupt and it could have been a spurious interrupt as well. > > > >The problem is that the interrupt handler unconditionally returns IRQ > >handled, which does not seem correct. Anyway I am not very familiar with > >this code so I may be missing the whole point. I would appreciate your > >comments on this. > > > > The handler does handle the interrupt - both status and data registers > are read so from the keyboard controller point of view the interrupt > has been handled even if we happen to discard the data. As far as I > know IRQ12 is never shared by BIOS... Vojtech, do you remember why we > request IRQ12 with IRQF_SHARED? I believe it was needed on PPC.
-- Vojtech Pavlik Director SuSE Labs - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
