linux-kernel - Re: [PATCH 4/5] riscv: dts: renesas: rzfive-smarc: Drop dma properties from SSI1 node

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Date:   Fri, 29 Sep 2023 09:35:53 +0100
From:   "Lad, Prabhakar" <prabhakar.csengg@...il.com>
To:     Samuel Holland <samuel.holland@...ive.com>
Cc:     Geert Uytterhoeven <geert+renesas@...der.be>,
        Magnus Damm <magnus.damm@...il.com>,
        Conor Dooley <conor+dt@...nel.org>,
        Paul Walmsley <paul.walmsley@...ive.com>,
        Palmer Dabbelt <palmer@...belt.com>,
        Albert Ou <aou@...s.berkeley.edu>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        linux-renesas-soc@...r.kernel.org, devicetree@...r.kernel.org,
        linux-riscv@...ts.infradead.org, linux-kernel@...r.kernel.org,
        Biju Das <biju.das.jz@...renesas.com>,
        Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>
Subject: Re: [PATCH 4/5] riscv: dts: renesas: rzfive-smarc: Drop dma
 properties from SSI1 node

Hi Samuel,

On Fri, Sep 29, 2023 at 1:30 AM Samuel Holland
<samuel.holland@...ive.com> wrote:
>
> Hi Prabhakar,
>
> On 2023-09-28 7:07 PM, Prabhakar wrote:
> > From: Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>
> >
> > With DMA enabled audio capture/playback has some echo noise. So for
> > now switch to PIO mode until fixed.
>
> Is it really appropriate to work around a Linux software bug with a DT change
> like this? Remember, the devicetrees are used by software other than Linux.
>
Agreed not a good idea, this worked with previous kernel version and I
wanted to make sure people using upstream kernel be aware of this
issue. As you mentioned this is not a correct approach Im happy for
this patch to be dropped from the series.

Cheers,
Prabhakar

> Regards,
> Samuel
>
> > Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>
> > ---
> >  arch/riscv/boot/dts/renesas/rzfive-smarc.dtsi | 5 +++++
> >  1 file changed, 5 insertions(+)
> >
> > diff --git a/arch/riscv/boot/dts/renesas/rzfive-smarc.dtsi b/arch/riscv/boot/dts/renesas/rzfive-smarc.dtsi
> > index a8573fdfd8b1..85f96e24a96e 100644
> > --- a/arch/riscv/boot/dts/renesas/rzfive-smarc.dtsi
> > +++ b/arch/riscv/boot/dts/renesas/rzfive-smarc.dtsi
> > @@ -6,3 +6,8 @@
> >   */
> >
> >  #include <arm64/renesas/rzg2ul-smarc.dtsi>
> > +
> > +&ssi1 {
> > +     /delete-property/ dmas;
> > +     /delete-property/ dma-names;
> > +};
>