Re: [PATCH RFC 3/3] arm64: dts: qcom: x1e78100-lenovo-thinkpad-t14s: add HDMI nodes

[Neil Armstrong]

On 06/09/2025 10:41, Jens Glathe wrote:
> On 21.08.25 15:53, Neil Armstrong wrote:
> > The Thinkpad T14s embeds a transparent 4lanes DP->HDMI transceiver
> > connected to the third QMP Combo PHY 4 lanes.
> [...]
> >   .../dts/qcom/x1e78100-lenovo-thinkpad-t14s.dtsi    | 44 ++++++++++++++++++++++
> >   1 file changed, 44 insertions(+)
> [...]
> > diff --git a/arch/arm64/boot/dts/qcom/x1e78100-lenovo-thinkpad-t14s.dtsi b/arch/arm64/boot/dts/qcom/x1e78100-lenovo-thinkpad-t14s.dtsi
> > index 4cf61c2a34e31233b1adc93332bcabef22de3f86..5b62b8c3123633360f249e3ecdc8ea23f44e8e09 100644
> > --- a/arch/arm64/boot/dts/qcom/x1e78100-lenovo-thinkpad-t14s.dtsi
> > +++ b/arch/arm64/boot/dts/qcom/x1e78100-lenovo-thinkpad-t14s.dtsi
> [...]
> > +&mdss_dp2 {
> > +    status = "okay";
> > +};
> > +
> > +&mdss_dp2_out {
> > +    data-lanes = <0 1 2 3>;
> > +};
> > +
>
> Hi Neil,
>
> shouldn't mdss_dp2_out also have the link-frequencies property?
>
> +    link-frequencies = /bits/ 64 <1620000000 2700000000 5400000000 8100000000>;
>
> Or is it something the bridge already negotiates?

No, indeed I'll add it, it will fall back to HBR2 anyway (as actually) if the link quality is low.

Neil

> with best regards
>
> Jens