Re: [PATCH RFC 0/7] Adding core support for wire-MSI bridges

From: Thomas Gleixner
Date: Wed Nov 04 2015 - 08:35:26 EST


Marc,

On Fri, 16 Oct 2015, Marc Zyngier wrote:
> On 16/10/15 02:55, Jiang Liu wrote:
> > There's a working to enable Intel VMD storage device, which
> > has the similar requirement. Basically a PCIe hierarchy is hidden
> > behind a parent PCIe device, so we need to use the PCIe irqs on parent
> > to de-multiple PCIe IRQs from hidden PCIe devices. Seems a chance for
> > consolidation here.
>
> Do you know if there is a 1-1 mapping between the interrupts seen by the
> parent device and those seen by the hidden devices? Or is it a case of
> having to demultiplex the MSIs? Looks like the former, but I'd like to
> be sure.

Yes, it's a demultiplexer. No 1:1 mapping.

> Sure, will do when I repost this (probably in a few weeks), and assuming
> this fits the bill for Thomas and the MBIGEN folks.

It doesn't look that bad and the resulting mbigen stuff is way less
horrible than it was before. So I agree this is a possible solution to
the problem.

Thanks,

tglx

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