Re: [PATCH 4/5] PCI: iproc: Add iProc PCIe MSI support

From: Ray Jui
Date: Thu Nov 19 2015 - 18:06:35 EST


Hi Arnd,

On 11/19/2015 12:31 AM, Arnd Bergmann wrote:
On Wednesday 18 November 2015 17:37:16 Ray Jui wrote:

I haven't spent too much time investigating, and am hoping to eventually
enable affinity support with an incremental patch in the future when I
have more time to investigate.

Is it possible that you have a set of MSIs per GIC interrupt (as Marc
suggested earlier) and that the way it is intended to be used is by
having each one of them target a different CPU? That way you can do
affinity by switching to a different MSI in .set_affinity(), I think
that is how the old style MSI all used to work when each CPU had its
own MSI register.

Arnd


Okay, I see that Xgene MSI has a very similar implementation to support MSI IRQ affinity. I plan to take a closer look and try it out in the future. But it likely won't be included in the current round of patch set.

Thanks,

Ray
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