Messages in this thread | | | Date | Mon, 2 May 2022 17:45:59 +0200 | From | Marek Behún <> | Subject | Re: irqdomain API: how to set affinity of parent irq of chained irqs? |
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On Mon, 02 May 2022 10:31:11 +0100 Marc Zyngier <maz@kernel.org> wrote:
> On Mon, 02 May 2022 09:21:37 +0100, > Marek Behún <kabel@kernel.org> wrote: > > > > Dear Marc, Thomas, > > > > we have encountered the following problem that can hopefully be put > > some light onto: What is the intended way to set affinity (and possibly > > other irq attributes) of parent IRQ of chained IRQs, when using the > > irqdomain API? > > Simples: you can't. What sense does it make to change the affinity of > the parent interrupt, given that its fate is tied to *all* of the > other interrupts that are muxed to it?
Dear Marc,
thank you for your answer. Still:
What about when we want to set the same affinity for all the chained interrupts?
Example: on Armada 385 there are 4 PCIe controllers. Each controller has one interrupt from which we trigger chained interrupts. We would like to configure each controller to trigger interrupt (and thus all chained interrupts in the domain) on different CPU core.
Moreover we would really like to do this in runtime, through sysfs, depending on for example whether there are cards plugged in the PCIe ports.
Maybe there should be some mechanism to allow to change affinity for whole irqdomain, or something?
Marek
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