Messages in this thread | | | Date | Mon, 24 Apr 2006 17:20:38 -0400 | From | Alan Cox <> | Subject | Re: better leve triggered IRQ management needed |
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On Mon, Apr 24, 2006 at 02:07:01PM -0700, Linus Torvalds wrote: > debugging standpoint. So even if it's just that every registered SA_SHIRQ > would get a heartbeat at least once every five seconds (and we'd limit it > to SA_SHIRQ exactly because a driver that doesn't have that set may get > confused if it gets extra interrupts), that might sound totally useless, > but it might actually help somebody who otherwise might just make a pretty > useless "the machine hung" bug-report.
Have to watch enable/disable_irq and the other races here.
> The fake interrupt could even print out a warning if somebody returns > SA_HANDLED (since normally there _shouldn't_ have been any work to handle > for it), and if that means that for somebody, things go from "the machine > hung" to "the machine got very slow, and printed out 'fake interrupt for > ide0 returned SA_HANDLED!'", that would potentially be a big debug aid.
There are high rate IRQ sources that would trigger that erratically due to races but it could be useful in some kind of "linux irqdebug" mode
> We've had our ass saved quite a few times now by the irq storm detector > ("irq X: nobody cared" and friends), which has helped debug irqs that > haven't been set up properly, that I'm convinced things like this might > well make a huge deal.
Yep
Alan -- "... and for $64000 question, could you get yourself vaguely familiar with the notion of on-topic posting?" -- Al Viro
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