From mboxrd@z Thu Jan  1 00:00:00 1970
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Date: Thu, 01 Jun 2006 11:44:39 +0200
From: Jan Kiszka <jan.kiszka@domain.hid>
MIME-Version: 1.0
Subject: Re: [Xenomai-core] io apic and shared irq questions
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To: "s.a." <sancelot@domain.hid>
Cc: xenomai@xenomai.org

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s.a. wrote:
> Hi,
>=20
> Regarding an embedded realtime system, I have got a communication board=

> on pci bus .
>=20
> I would like it's interrupt not being shared (with usb) , because the
> component receives an it every 100us and is realtime determinist.
> I looked at how was routed IRQ's with the io apic , although it is able=

> to use 24 irq's, linux always share my PCI boards IRQ with another
> component and do not use all the 24 irq's range capability of ioapic.
>=20
> Do you think it is possible to program the ioapic in order to have a
> better irq mapping and avoid this problem and use all the range of
> availbale vectors ?

Logical IRQ numbers are one side, but you first have to find out if the
PCI components do not share the same *physical* line. Dependent on the
system design, there should be some way to flip those line assignment,
either by moving to another extension slot or even by playing with
jumpers (PC/104plus boards may provide this e.g.).

Jan



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