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Date: Mon, 10 Aug 2009 12:43:32 +0300
From: Avi Kivity <avi@redhat.com>
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Subject: Re: [Qemu-devel] [PATCH 1/2] Route PC irqs to ISA bus instead of
	i8259 directly
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To: Alexander Graf <agraf@suse.de>
Cc: sassmann@redhat.com, "qemu-devel@nongnu.org" <qemu-devel@nongnu.org>, Olaf Dabrunz <Olaf.Dabrunz@gmx.net>

On 08/10/2009 12:04 PM, Alexander Graf wrote:
>
> Am 09.08.2009 um 18:44 schrieb Avi Kivity <avi@redhat.com>:
>
>> A PC has its motherboard IRQ lines connected to both the PIC and IOAPIC.
>> Currently, qemu routes IRQs to the PIC which then calls the IOAPIC, an
>> incestuous arrangement.  In order to clean this up, create a new ISA IRQ
>> abstraction, and have devices raise ISA IRQs (which in turn raise the 
>> i8259
>> IRQs as usual).
>
> Is this really true? From my understanding the PIC in modern systems 
> is emulated through the IOAPIC, which is the reason we have legacy 
> interrupts.
>

For the PC emulated by qemu, it is certainly true.  I don't know for 
sure about modern PCs, but I bet they do respond to the PIC io ports.

-- 
error compiling committee.c: too many arguments to function