On Fri, 23 Mar 2007 00:04:07 +0100 Bernhard Walle <bwalle@xxxxxxx> wrote: > * Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> [2007-03-22 22:09]: > > On Tue, 20 Mar 2007 16:00:27 +0100 > > Bernhard Walle <bwalle@xxxxxxx> wrote: > > > > > On IA64, the timer interrupt is not (always?) zero as it is on x86 platforms. > > > Also, the timer interrupt is CPU-local. Two things need to be changed to make > > > the irqpoll option make also working on IA64: > > > > > > o Call note_interrupt() also on CPU-local interrupts in __do_IRQ(). > > > o Set a variable timer_irq to the value of the timer interrupt > > > after the timer interrupt has been registered and assigned. > > > > > > That requires changes in Linux-generic files. The default of timer_irq is 0, so > > > the patch doesn't break i386/x86_64. However, other platforms also may also > > > have a timer interrupt non-equal to zero, so they can also use the new > > > set_timer_interrupt() function. > > > > Couple of things.. > > > > I think the term 'timer_interrupt' is a bit generic-sounding. Would it be > > better to call it irqpoll_interrupt? After all, some architecture might > > want to use, umm, the keyboard interrupt to trigger IRQ polling ;) > > Well, the documentation of irqpoll says that it's called on the timer > interrupt. But maybe also the documentation should be changed. :) > > > Also, the code presently passes the magic IRQ number into the generic IRQ > > code. I wonder if we'd get a more pleasing result if we were to make the > > generic IRQ code call _out_ to the architecture: > > I think I have a third solution. There's already IRQF_TIMER, and > that's used and defined in a few architectures already (like Sh), so > why not simply use that here. Maybe we should introduce IRQF_IRQPOLL, > but the concept would be the same. If we don't take care of shared > interrupt handlers (and I think sharing the timer interrupt is a > _very_ bad idea, are there architectures that do this?), the could > would look like this (+ the change in __do_IRQ). > > What's your opinion on this approach? Of course, we would have to make > sure that IRQF_TIMER is defined on _every_ architectures, but that > would give us the chance to find out each architecture that also has a > timer interrupt != 0. > > > Index: mainline-msi-init/arch/ia64/kernel/time.c > =================================================================== > --- mainline-msi-init.orig/arch/ia64/kernel/time.c > +++ mainline-msi-init/arch/ia64/kernel/time.c > @@ -235,7 +235,7 @@ ia64_init_itm (void) > > static struct irqaction timer_irqaction = { > .handler = timer_interrupt, > - .flags = IRQF_DISABLED, > + .flags = IRQF_DISABLED | IRQF_TIMER, > .name = "timer" > }; > > Index: mainline-msi-init/arch/x86_64/kernel/time.c > =================================================================== > --- mainline-msi-init.orig/arch/x86_64/kernel/time.c > +++ mainline-msi-init/arch/x86_64/kernel/time.c > @@ -320,7 +320,7 @@ void __init stop_timer_interrupt(void) > } > > static struct irqaction irq0 = { > - timer_interrupt, IRQF_DISABLED, CPU_MASK_NONE, "timer", NULL, NULL > + timer_interrupt, IRQF_DISABLED | IRQF_TIMER, CPU_MASK_NONE, "timer", NULL, NULL > }; > > void __init time_init(void) > Index: mainline-msi-init/kernel/irq/spurious.c > =================================================================== > --- mainline-msi-init.orig/kernel/irq/spurious.c > +++ mainline-msi-init/kernel/irq/spurious.c > @@ -146,7 +146,7 @@ void note_interrupt(unsigned int irq, st > > if (unlikely(irqfixup)) { > /* Don't punish working computers */ > - if ((irqfixup == 2 && irq == 0) || action_ret == IRQ_NONE) { > + if ((irqfixup == 2 && (desc->action->flags & IRQF_TIMER)) || action_ret == IRQ_NONE) { > int ok = misrouted_irq(irq); > if (action_ret == IRQ_NONE) > desc->irqs_unhandled -= ok; Seems sane. Or we could add a new flag specifically for this purpose: IRQF_IRQPOLL_IRQ? - To unsubscribe from this list: send the line "unsubscribe linux-ia64" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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