linux-kernel - Re: [PATCH v4 4/4] arm64/dts/qcom/sm8250: remove assigned-clock-rate property for mdp clk

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Date:   Fri, 4 Mar 2022 02:50:50 +0300
From:   Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
To:     Vinod Polimera <quic_vpolimer@...cinc.com>
Cc:     dri-devel@...ts.freedesktop.org, linux-arm-msm@...r.kernel.org,
        freedreno@...ts.freedesktop.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, robdclark@...il.com,
        dianders@...omium.org, swboyd@...omium.org,
        quic_kalyant@...cinc.com
Subject: Re: [PATCH v4 4/4] arm64/dts/qcom/sm8250: remove assigned-clock-rate
 property for mdp clk

On Thu, 3 Mar 2022 at 12:40, Vinod Polimera <quic_vpolimer@...cinc.com> wrote:
>
> Kernel clock driver assumes that initial rate is the
> max rate for that clock and was not allowing it to scale
> beyond the assigned clock value.
>
> Drop the assigned clock rate property and vote on the mdp clock as per
> calculated value during the usecase.
>
> Fixes: 7c1dffd471("arm64: dts: qcom: sm8250.dtsi: add display system nodes")

Please remove the Fixes tags from all commits. Otherwise the patches
might be picked up into earlier kernels, which do not have a patch
adding a vote on the MDP clock.

> Signed-off-by: Vinod Polimera <quic_vpolimer@...cinc.com>
> ---
>  arch/arm64/boot/dts/qcom/sm8250.dtsi | 9 ++-------
>  1 file changed, 2 insertions(+), 7 deletions(-)
>
> diff --git a/arch/arm64/boot/dts/qcom/sm8250.dtsi b/arch/arm64/boot/dts/qcom/sm8250.dtsi
> index fdaf303..2105eb7 100644
> --- a/arch/arm64/boot/dts/qcom/sm8250.dtsi
> +++ b/arch/arm64/boot/dts/qcom/sm8250.dtsi
> @@ -3164,9 +3164,6 @@
>                                  <&dispcc DISP_CC_MDSS_MDP_CLK>;
>                         clock-names = "iface", "bus", "nrt_bus", "core";
>
> -                       assigned-clocks = <&dispcc DISP_CC_MDSS_MDP_CLK>;
> -                       assigned-clock-rates = <460000000>;
> -
>                         interrupts = <GIC_SPI 83 IRQ_TYPE_LEVEL_HIGH>;
>                         interrupt-controller;
>                         #interrupt-cells = <1>;
> @@ -3191,10 +3188,8 @@
>                                          <&dispcc DISP_CC_MDSS_VSYNC_CLK>;
>                                 clock-names = "iface", "bus", "core", "vsync";
>
> -                               assigned-clocks = <&dispcc DISP_CC_MDSS_MDP_CLK>,
> -                                                 <&dispcc DISP_CC_MDSS_VSYNC_CLK>;
> -                               assigned-clock-rates = <460000000>,
> -                                                      <19200000>;
> +                               assigned-clocks = <&dispcc DISP_CC_MDSS_VSYNC_CLK>;
> +                               assigned-clock-rates = <19200000>;
>
>                                 operating-points-v2 = <&mdp_opp_table>;
>                                 power-domains = <&rpmhpd SM8250_MMCX>;
> --
> 2.7.4
>


-- 
With best wishes
Dmitry