From mboxrd@z Thu Jan  1 00:00:00 1970
From: Jes Sorensen <jes@sgi.com>
Date: Thu, 02 Aug 2007 07:27:23 +0000
Subject: Re: [RFC][PATCH 0/2] SN platform needs platform_irq_to_vector?
Message-Id: <46B1875B.9070400@sgi.com>
List-Id: <linux-ia64.vger.kernel.org>
References: <1186028871.3875.12.camel@kane-linux>
In-Reply-To: <1186028871.3875.12.camel@kane-linux>
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To: linux-ia64@vger.kernel.org

Hi Kenji-san

I believe we need this property, but I am not 100% sure, so I am
going to forward your patch to our team who maintain the IRQ code
for Altix.

Mike, Aaron or John, would one of you have time to take a look at
this?

Thanks,
Jes


Kenji Kaneshige wrote:
> Hi Jes-san, Russ-san, Christoph-san and SN platform developers,
> 
> I glanced over the SN code, and I found SN platform doesn't have SN
> specific irq_to_vector() function, though it has SN specific
> local_vector_to_irq() function. I guess it was OK because maybe SN
> platform depends on irq = vector and old generic irq_to_vector() was
> just returning the same value as irq.
> 
> The irq_to_vector() function, however, has been changed by vector
> domain support, and currently it can return the different value from
> irq, even when VECTOR_DOMAIN_PERCPU is not enabled. This can happen
> when an interrupt thorough I/O SAPIC is unregistered and another
> interupt is registered. So if my guess (SN platform depends on irq =
> vector) is true, something problem might happen on SN platform when
> PCI hotplugging or driver reloading.
> 
> If it is true that SN platform depends on irq = vector, we need to
> implement SN specific irq_to_vector() that returns the same value as
> irq, I think. I made sample patches to implement platform specific
> irq_to_vector() as follows. Note that [PATCH 2/2] is not tested yet
> because I don't have any SN platform unfortunately.
> 
>     [PATCH 1/2] Add base support for platform_irq_to_vector()
>     [PATCH 2/2] Implement platform_irq_to_vector() for SN
> 
> Could you give me comments?
> 
> Thanks,
> Kenji Kaneshige
>