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Message-ID: <4ce0aee2-4abf-36ea-37b7-063bc8332913@quicinc.com>
Date:   Wed, 19 Apr 2023 13:07:18 -0700
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Subject: Re: [Freedreno] [PATCH 0/5] MDSS reg bus interconnect
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To:     Konrad Dybcio <konrad.dybcio@linaro.org>,
        Rob Clark <robdclark@gmail.com>,
        Abhinav Kumar <quic_abhinavk@quicinc.com>,
        Dmitry Baryshkov <dmitry.baryshkov@linaro.org>,
        Sean Paul <sean@poorly.run>, David Airlie <airlied@gmail.com>,
        Daniel Vetter <daniel@ffwll.ch>,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Krishna Manikandan <quic_mkrishn@quicinc.com>
CC:     <devicetree@vger.kernel.org>, <linux-arm-msm@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>, <dri-devel@lists.freedesktop.org>,
        "Marijn Suijten" <marijn.suijten@somainline.org>,
        <freedreno@lists.freedesktop.org>
References: <20230417-topic-dpu_regbus-v1-0-06fbdc1643c0@linaro.org>
From:   Jeykumar Sankaran <quic_jeykumar@quicinc.com>
In-Reply-To: <20230417-topic-dpu_regbus-v1-0-06fbdc1643c0@linaro.org>
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On 4/17/2023 8:30 AM, Konrad Dybcio wrote:
> Apart from the already handled data bus (MAS_MDP_Pn<->DDR), there's
> another path that needs to be handled to ensure MDSS functions properly,
> namely the "reg bus", a.k.a the CPU-MDSS interconnect.
> 
> Gating that path may have a variety of effects.. from none to otherwise
> inexplicable DSI timeouts..
Current DPU driver already votes on the "reg bus" indirectly through the 
display AHB clock handle[<&dispcc DISP_CC_MDSS_AHB_CLK>] in DTSI. Can 
you provide more details on the issues that warrants this patch series?

Thanks
Jeykumar S
> 
> This series tries to address the lack of that.
> 
> Example path:
> 
> interconnects = <&bimc MASTER_AMPSS_M0 0 &config_noc SLAVE_DISPLAY_CFG 0>;
> 
> Signed-off-by: Konrad Dybcio <konrad.dybcio@linaro.org>
> ---
> Konrad Dybcio (5):
>        dt-bindings: display/msm: Add reg bus interconnect
>        drm/msm/dpu1: Rename path references to mdp_path
>        drm/msm/mdss: Rename path references to mdp_path
>        drm/msm/mdss: Handle the reg bus ICC path
>        drm/msm/dpu1: Handle the reg bus ICC path
> 
>   .../bindings/display/msm/mdss-common.yaml          |  1 +
>   drivers/gpu/drm/msm/disp/dpu1/dpu_core_perf.c      | 10 +++----
>   drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c            | 34 ++++++++++++++++-----
>   drivers/gpu/drm/msm/disp/dpu1/dpu_kms.h            |  5 ++--
>   drivers/gpu/drm/msm/msm_mdss.c                     | 35 ++++++++++++++--------
>   5 files changed, 57 insertions(+), 28 deletions(-)
> ---
> base-commit: d3f2cd24819158bb70701c3549e586f9df9cee67
> change-id: 20230417-topic-dpu_regbus-abc94a770952
> 
> Best regards,