RE: PCI Express

Nguyen, Tom L
2005-03-08T19:29:29Z

On Monday, March 07, 2005 8:41 PM Colin wrote:
> On Altix systems, we have a set of "Interrupt Registers" in Memory
Address
> 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
these
> 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
Message)
> 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.

Thanks,
Long