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Subject: Re: Does it need to implement irq_set_type method in the ioapic_chip?
From: "H. Peter Anvin" <hpa@zytor.com>
Date: Wed, 19 Feb 2014 05:28:15 -0800
To: Thomas Gleixner <tglx@linutronix.de>, carl peng <carlpeng008@gmail.com>
CC: mingo@redhat.com, x86@kernel.org, pingfank@linux.vnet.ibm.com,
        yoshihiro.yunomae.ez@hitachi.com, linux-kernel@vger.kernel.org
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In the casee of your ACPI-enabled AMBA device I believe the BIOS, which provides the ACPI tables, is expected to set the interrupt type.

On February 19, 2014 4:07:09 AM PST, Thomas Gleixner <tglx@linutronix.de> wrote:
>On Wed, 19 Feb 2014, carl peng wrote:
>> At last, the device will be connected to AMBA bus, so the interrupt
>> pin will be connected to IOAPIC through AMBA bus. The device now
>> is in the pre-silicon verification stage.
>> 
>> So my question is the same:
>> Why does APIC driver not implement the irq_set_type method?  if
>
>Because we do not need it. All devices are properly connected and
>configured by the BIOS and bus discovery.
>
>> implement it, will supply more free space for the device driver
>> developer(they can set the interrupttrigger mode by calling
>request_irq).
>
>There are 3 different mechanisms already to tell the kernel to
>configure a particular irq line: ACPI, MP Tables and SFI.
>
>That's the way x86 does its interrupt configuration and there is no
>need to provide another one.
>
>Thanks,
>
>	tglx

-- 
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