Re: [PATCH 1/5] arm64: dts: qcom: sc8280xp: Add missing dwc3 quirks

Manivannan Sadhasivam
2023-03-28T09:39:09Z

On Tue, Mar 28, 2023 at 10:54:53AM +0200, Johan Hovold wrote:
> On Sat, Mar 25, 2023 at 10:22:13PM +0530, Manivannan Sadhasivam wrote:
> > Add missing quirks for the USB DWC3 IP.
>
> This is not an acceptable commit message generally and certainly not for
> something that you have tagged for stable.
>
> At a minimum, you need to describe why these are needed and what the
> impact is.
>

I can certainly improve the commit message. But usually the quirks are copied
from the downstream devicetree where qualcomm engineers would've added them
based on the platform requirements.

> Also, why are you sending as part of a series purporting to enable
> runtime PM when it appears to be all about optimising specific gadget
> applications?
>

It's not related to this series I agree but just wanted to group it with a
series touching usb so that it won't get lost.

I could respin it separately though in v2.

> Did you confirm that the below makes any sense or has this just been
> copied verbatim from the vendor devicetree (it looks like that)?
>

As you've mentioned, most of the quirks are for gadget mode which is not
supported by the upstream supported boards. So I haven't really tested them but
for I assumed that Qcom engineers did.

> The fact that almost none of the qcom SoCs sets these also indicates
> that something is not right here.
>
> > Cc: stable@vger.kernel.org # 5.20
> > Fixes: 152d1faf1e2f ("arm64: dts: qcom: add SC8280XP platform")
> > Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
> > ---
> > arch/arm64/boot/dts/qcom/sc8280xp.dtsi | 14 ++++++++++++++
> > 1 file changed, 14 insertions(+)
> >
> > diff --git a/arch/arm64/boot/dts/qcom/sc8280xp.dtsi b/arch/arm64/boot/dts/qcom/sc8280xp.dtsi
> > index 0d02599d8867..266a94c712aa 100644
> > --- a/arch/arm64/boot/dts/qcom/sc8280xp.dtsi
> > +++ b/arch/arm64/boot/dts/qcom/sc8280xp.dtsi
> > @@ -3040,6 +3040,13 @@ usb_0_dwc3: usb@a600000 {
> > iommus = <&apps_smmu 0x820 0x0>;
> > phys = <&usb_0_hsphy>, <&usb_0_qmpphy QMP_USB43DP_USB3_PHY>;
> > phy-names = "usb2-phy", "usb3-phy";
> > + snps,hird-threshold = /bits/ 8 <0x0>;
> > + snps,usb2-gadget-lpm-disable;
>
> Here you are disabling LPM for gadget mode, which makes most of the
> other properties entirely pointless.
>
> > + snps,is-utmi-l1-suspend;
> > + snps,dis-u1-entry-quirk;
> > + snps,dis-u2-entry-quirk;
>
> These appear to be used to optimise certain gadget application and
> likely not something that should be set in a dtsi.
>

I will cross check these with Qcom and respin accordingly.

- Mani

> > + snps,has-lpm-erratum;
> > + tx-fifo-resize;
>
> Same here.
>
> > port {
> > usb_0_role_switch: endpoint {
>
> Johan

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