Re: [PATCH V15 00/15] irqchip: Add LoongArch-related irqchip drivers

[Jianmin Lv]

On 2022/7/18 下午2:39, Marc Zyngier wrote:
> On Mon, 18 Jul 2022 02:07:21 +0100,
> Jianmin Lv <lvjianmin@xxxxxxxxxxx> wrote:
> > On 2022/7/17 下午10:49, Marc Zyngier wrote:
> > > On Sun, 17 Jul 2022 12:29:05 +0100,
> > > Jianmin Lv <lvjianmin@xxxxxxxxxxx> wrote:
> > > > On 2022/7/17 下午6:02, Marc Zyngier wrote:
> > > > > But the other issue is that you seem to call this function from two
> > > > > different locations. This cannot be right, as there should be only one
> > > > > probe order, and not multiple.
> > > >
> > > > As we described two IRQ models(Legacy and Extended) in this cover
> > > > letter, the parent domain of MSI domain can be htvec domain(Legacy) or
> > > > eiointc domain(Extended). In MADT, only one APIC(HTPIC for htvec or
> > > > EIOPIC for eiointc) is allowed to pass into kernel, and then in the
> > > > irqchip driver, only one kind APIC of them can be parsed from MADT, so
> > > > we have to support two probe order for them.
> > >
> > > Do you really have the two variants in the wild? Or is this just
> > > because this is a possibility?
> >
> > Currently, there are not CPUs(used for PC and server) based on
> > LoongArch shipped with only HTPIC, but with both HTPIC and EIOPIC, we
> > just want to provide two choices for designers(but obviously, EIOPIC
> > may be enough currently). Do you think we don't have to do like this,
> > yes? If so, maybe we don't have to support ACPI-way entry for htvec
> > currently, and do the work in future if required.
>
> If the existing HW is only following the 'Extended' model, then I'd
> suggest you only support this for now. It has two effects:
>
> - it simplifies the current code, making it more maintainable and
>    easier to reason about
>
> - it sends the message to integrators that 'Extended' is the correct
>    model, and that it is what they should support
>
> Now, we don't have much time left to get this series into -next (I
> will be closing the tree to new features this week, and only queue
> fixes).
>
> So whatever you need to do, please do it quickly so that we can have
> at least some of this in 5.20.
>
> Thanks,
>
> 	M.

Ok, Marc, thanks for your suggestion, got it, I'll remove 'Legacy' mode 
support and send next version as soon as possible.