RE: [PATCH] fix PCI interrupt setting for ia64

[Kenji Kaneshige]

Hi,

Sorry, I misunderstood your concern.

I think you are right. Probe_irq_on() still have another problems even if my
patch
is applied. For example, if buggy PCI device generates interrupts during its
device
driver calls probe_irq_on(), these interrupts might be considered as
spurious and
IRQ probing will fail. I think this is another problem than I pointed out.

In addition to this, if probe_irq_on() is used for PCI interrupts (level
triggered),
interrupts are generated repeatedly because there are no handlers which
clears
these interrupt request. But I think this is not a problem, because these
interrupts
will be masked by probe_irq_on() or probe_irq_off() soon. If this is a
problem, I think
probe_irq_on() should never be used for PCI (level triggered) interrupt
probing.

Regards,
Kenji Kaneshige


> -----Original Message-----
> From: linux-ia64-owner@xxxxxxxxxxxxxxx
> [mailto:linux-ia64-owner@xxxxxxxxxxxxxxx]On Behalf Of Takayoshi Kochi
> Sent: Thursday, March 11, 2004 10:35 AM
> To: kaneshige.kenji@xxxxxxxxxxxxxx
> Cc: davidm@xxxxxxxxxx; linux-ia64@xxxxxxxxxxxxxxx;
> linux-kernel@xxxxxxxxxxxxxxx
> Subject: Re: [PATCH] fix PCI interrupt setting for ia64
>
>
> Hi,
>
> From: Kenji Kaneshige <kaneshige.kenji@xxxxxxxxxxxxxx>
> Subject: RE: [PATCH] fix PCI interrupt setting for ia64
> Date: Thu, 11 Mar 2004 09:34:06 +0900
>
> > Hi,
> >
> > I'm sorry that the report falls behind. I wanted to check out by using
> > real device driver which uses a probe_irq_on(), but I don't
> have appropriate
> > environment now.
> >
> > Though I didn't check out on a real machine yet, I believe my
> patch doesn't
> > have any influence on probe_irq_on() because current
> probe_irq_on() calls
> > startup callback to unmask the RTEs as you said before.
>
> My concern was that if there's a buggy PCI device that raises
> interrupts all the time until it's initialized by some device driver,
> probe_irq_on() would not work as expected regardless of whether
> your patch is applied or not.  I thought masking the interrupt line
> doesn't work around this case.
>
> ---
> Takayoshi Kochi <t-kochi@xxxxxxxxxxxxx>
> -
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