linux-kernel - Re: [PATCH v7 6/6] drm/msm/dp: Add DisplayPort controller for QCS8300

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <brculyyu3dgc5nkj2cuzv3jkjzcouljy5o4jwr6mw33r6i7gt7@j6ur7yvwmky5>
Date: Tue, 19 Aug 2025 10:59:31 +0300
From: Dmitry Baryshkov <dmitry.baryshkov@....qualcomm.com>
To: Yongxing Mou <yongxing.mou@....qualcomm.com>
Cc: Rob Clark <robin.clark@....qualcomm.com>,
        Dmitry Baryshkov <lumag@...nel.org>,
        Abhinav Kumar <abhinav.kumar@...ux.dev>,
        Jessica Zhang <jessica.zhang@....qualcomm.com>,
        Sean Paul <sean@...rly.run>,
        Marijn Suijten <marijn.suijten@...ainline.org>,
        Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
        Maxime Ripard <mripard@...nel.org>,
        Thomas Zimmermann <tzimmermann@...e.de>,
        David Airlie <airlied@...il.com>, Simona Vetter <simona@...ll.ch>,
        Rob Herring <robh@...nel.org>,
        Krzysztof Kozlowski <krzk+dt@...nel.org>,
        Conor Dooley <conor+dt@...nel.org>,
        Neil Armstrong <neil.armstrong@...aro.org>,
        Kuogee Hsieh <quic_khsieh@...cinc.com>,
        Bjorn Andersson <andersson@...nel.org>,
        Konrad Dybcio <konradybcio@...nel.org>, linux-arm-msm@...r.kernel.org,
        dri-devel@...ts.freedesktop.org, freedreno@...ts.freedesktop.org,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v7 6/6] drm/msm/dp: Add DisplayPort controller for QCS8300

On Tue, Aug 19, 2025 at 11:33:33AM +0800, Yongxing Mou wrote:
> The Qualcomm QCS8300 platform comes with one DisplayPort controller
> with same base offset as SM8650. But it requires new compatible string
> because QCS8300 controller supports 4 MST streams. 4 MST streams will
> be enabled as part of MST feature support. Currently, using SM8650 as
> fallback to enable SST on QCS8300.

Hmm, no, you are not using SM8650 as a fallback. You are using the data
structure for SM8650 for QCS8300. That's a different thing. It would
have been using SM8650 as fallback, if you had declared device with two
compatibles, qcom,qcs8300-dp and qcom,sm8650-dp, and then relied on the
second entry (only) to provide a match and data.

Exactly the same comment applies to the UBWC patch.

> 
> Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@....qualcomm.com>
> Signed-off-by: Yongxing Mou <yongxing.mou@....qualcomm.com>
> ---
>  drivers/gpu/drm/msm/dp/dp_display.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/msm/dp/dp_display.c
> index d87d47cc7ec3eb757ac192c411000bc50b824c59..bb4660585849d1a67921a28e7e12422e0c327ab2 100644
> --- a/drivers/gpu/drm/msm/dp/dp_display.c
> +++ b/drivers/gpu/drm/msm/dp/dp_display.c
> @@ -187,6 +187,7 @@ static const struct msm_dp_desc msm_dp_desc_x1e80100[] = {
>  };
>  
>  static const struct of_device_id msm_dp_dt_match[] = {
> +	{ .compatible = "qcom,qcs8300-dp", .data = &msm_dp_desc_sm8650 },
>  	{ .compatible = "qcom,sa8775p-dp", .data = &msm_dp_desc_sa8775p },
>  	{ .compatible = "qcom,sc7180-dp", .data = &msm_dp_desc_sc7180 },
>  	{ .compatible = "qcom,sc7280-dp", .data = &msm_dp_desc_sc7280 },
> 
> -- 
> 2.34.1
> 

-- 
With best wishes
Dmitry