Re: Problem with 2.6.17-mm2

[Andrew Morton <akpm@osdl.org>]

On Sun, 25 Jun 2006 19:24:06 +0200
Thomas Gleixner <tglx@linutronix.de> wrote:

> Andrew,
> 
> On Sun, 2006-06-25 at 03:49 -0700, Andrew Morton wrote:
> > OK, thanks.
> > 
> > > 1) A lot of "unexpected IRQ trap at vector X" for X=[09,07]
> > 
> > hm, ack_bad_irq().  That isn't supposed to happen.
> > 
> > Ingo, Thomas - it's possible that -mm2's genirq is affecting x86?
> 
> I did some tests by asserting spurious interrupts. genirq is just making
> them visible, backing out the genirq changes makes them invisible again.
> 
> The reason is:
> 
> ack_bad_irq() in !genirq is only called, when no hw_irq_controller has
> been installed. The interrupts in question have the PIC/APIC/IOAPIC
> functions installed.
> 
> Now when a spurios interrupt comes in we do
> 
> 	desc->handler->ack(irq);
> 
> 	if (!desc->action)
> 		goto out;
> 
> So in fact this just silently acks spurious interrupts which have an
> hw_irq_controller assigned. If there is no action, then nothing has
> called setup_irq/request_irq for this interrupt line and therefor it is
> an spurious interrupt which should not happen.
> 
> 
> genirq makes these visible and informs noisily about those events. 
> 

hm, OK.  I guess we can let it ride for now.  Later we can decide whether
we need to shut that warning up.  I suspect we should, if the machine's
working OK.
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