RE: PCI Express

From: Nguyen, Tom L <>
Date: 2005-03-09 06:29:29
On Monday, March 07, 2005 8:41 PM Colin wrote:
> On Altix systems, we have a set of "Interrupt Registers" in Memory
> Space that is initialized to target specific CPUs.  The way we 
> initialize a card's MSI is:
> 1.  The Target Address is One of these "Interrupt Registers"
> 2.  The Data Payload is the IRQ plus some special Altix bits.
> This memory write causes the "Interrupt Chipset" to generate a LINTR
> message to the configured targeted cpu with the IRQ.  Ofcourse, these
> registers are Altix Platform specific.  Moreover, we have chunks of
> registers all over the place.

Your solution is Altix chipset specific. MSI affects other architectures
too. General solution would almost certainly be a better one.

> Is there a more direct mechanism to generate an interrupt(LINTR
> to a Processor?  

I agree with Jesse's comment.

> With Altix, it's always interesting, with respect to "just work" with 
> typical ia64 code base.  Hopefully, it will work cleaner compared to 
> some of our other efforts.
> Are you the maintainer for the MSI code?

I suggest you move any discussion or any proposed changes to LKML
because MSI affects other architectures too. Again, general solution
would almost certainly be a better one.

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Received on Tue Mar 8 14:44:32 2005

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