# Re: \[PATCH\] arm64: dts: allwinner: a64: Drop PMU node

- From: Vasily Khoruzhick \<anarsoul@gmail.com\>
- Date: 2019-08-06 20:52:47 
- List: linux-arm-kernel
- Page: https://ratatoskr.run/linux-arm-kernel/2019/08/8170952
- Thread: https://ratatoskr.run/linux-devicetree/2019/08/8170921/t.md

```text
On Tue, Aug 6, 2019 at 1:19 PM Harald Geyer [ref] wrote:
>
> Vasily Khoruzhick writes:
> > On Tue, Aug 6, 2019 at 7:35 AM Robin Murphy [ref] wrote:
> > >
> > > On 06/08/2019 15:01, Vasily Khoruzhick wrote:
> > > > Looks like PMU in A64 is broken, it generates no interrupts at all and
> > > > as result 'perf top' shows no events.
> > >
> > > Does something like 'perf stat sleep 1' at least count cycles correctly?
> > > It could well just be that the interrupt numbers are wrong...
> >
> > Looks like it does, at least result looks plausible:
>
> I'm using perf stat regularly (cache benchmarks) and it works fine.
>
> Unfortunately I wasn't aware that perf stat is a poor test for
> the interrupts part of the node, when I added it. So I'm not too
> surprised I got it wrong.
>
> However, it would be unfortunate if the node got removed completely,
> because perf stat would not work anymore. Maybe we can only remove
> the interrupts or just fix them even if the HW doesn't work?

I'm not familiar with PMU driver. Is it possible to get it working
without interrupts?

>
> Harald

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