Messages in this thread | | | Date | Fri, 01 Aug 2014 15:51:50 +0100 | From | Marc Zyngier <> | Subject | Re: [PATCH 4/4 V3] irqchip: gicv2m: Add support for multiple MSI for ARM64 GICv2m |
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Hi Suravee,
On 01/08/14 15:36, Suravee Suthikulanit wrote: > On 7/30/2014 10:16 AM, Marc Zyngier wrote: >> Why do we need this complexity at all? Is there any case where we'd want >> to limit ourselves to a single vector for MSI? > > I think the ARM64 GICv2m should not be the limitation for the devices > multiple MSI if there is no real hardware/design limitation. > >> arm64 is a new enough architecture so that we can expect all interrupt controllers to cope >> with that. > > I am not sure if I understand this comment. > > We are not forcing all interrupt controllers for ARM64 to handle > multi-MSI. They have the option to support if multi-MSI if they want > to. I just think that we should not put the architectural limit here.
Let me be clearer: I think we should put the burden of *not* handling multi-MSI on interrupt controllers. Here, you're making the architectural default to be "I don't support multi-MSI", hence having to override global vectors and such for well behaved MSI controllers like GICv2m and GICv3 ITS.
Let's only support multi-MSI for the time being. If someone comes up with a silly old MSI controller that can't deal with it, we'll address the issue at that problem.
Thanks,
M. -- Jazz is not dead. It just smells funny...
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