Date: Fri, 24 Sep 2004 15:29:14 +0900
From: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Subject: Re: [ACPI] [PATCH] PCI IRQ resource deallocation support [2/3]
In-reply-to: <20040924.145229.108814142.t-kochi@bq.jp.nec.com>
To: Takayoshi Kochi <t-kochi@bq.jp.nec.com>
Cc: bjorn.helgaas@hp.com, acpi-devel@lists.sourceforge.net,
       kaneshige.kenji@soft.fujitsu.com, akpm@osdl.org, greg@kroah.com,
       len.brown@intel.com, tony.luck@intel.com, linux-kernel@vger.kernel.org,
       linux-ia64@vger.kernel.org
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Hi Takayoshi,

Thank you for feedback.

Takayoshi Kochi wrote:
>> > Why do we need to fiddle with dev->irq?  I think it should
>> > just be undefined after acpi_pci_irq_disable().
>> 
>> I had been considering what the "undefined dev->irq" was.
>> In fact, I had other ideas that was clearing it by zero or
>> -1 (0xffffffff). But I didn't know if we can use these values
>> as a undefined IRQ number. So I'm clearing it by the value
>> which was assigned by PCI core code (pci_read_irq()) before
>> acpi_pci_irq_enable() was called. 
> 
> I think it has little sense in restoring value from the configuration
> space to dev->irq or clearing it.
> 
> If we do preventive programming, it may be worth
> trying to define some magic constant (e.g. PCI_UNDEFINED_IRQ) and
> panic/BUG when the irq is being enabled.
> Otherwise, leaving dev->irq as it is would be ok.

Hmm, I think you are right.
I'll change my patch to leave dev->irq as it is. And then I'll
investigate about defining PCI_UNDEFINED_IRQ.

In fact, I posted updated patches a little before. I'll re-post
it with your feedback :-)

Thanks,
Kenji Kaneshige

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