linux-kernel - Re: [PATCH v3 36/38] drm/msm/dpu: use msm_dp_get_mst_intf

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Message-ID: <exfflgjky4zgqa7tnudfteeosncr6nsuwqadxnfftxtjay6hke@fxru2weupuwt>
Date: Wed, 27 Aug 2025 02:42:32 +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>,
        David Airlie <airlied@...il.com>, Simona Vetter <simona@...ll.ch>,
        linux-arm-msm@...r.kernel.org, dri-devel@...ts.freedesktop.org,
        freedreno@...ts.freedesktop.org, linux-kernel@...r.kernel.org,
        Abhinav Kumar <quic_abhinavk@...cinc.com>
Subject: Re: [PATCH v3 36/38] drm/msm/dpu: use msm_dp_get_mst_intf_id() to
 get the intf id

On Mon, Aug 25, 2025 at 10:16:22PM +0800, Yongxing Mou wrote:
> From: Abhinav Kumar <quic_abhinavk@...cinc.com>
> 
> Use msm_dp_get_mst_intf_id() to get the interface ID for the DP MST
> controller as the intf_id is unique for each MST stream of each
> DP controller.

I think we have one sensible exception: SC8180X, where we have several
DP controllers and one shared DP interface, but let's forget about it
for now...

> 
> Signed-off-by: Abhinav Kumar <quic_abhinavk@...cinc.com>
> Signed-off-by: Yongxing Mou <yongxing.mou@....qualcomm.com>
> ---
>  drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c | 51 +++++++++++++++++++++++++----
>  1 file changed, 44 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> index 05e5f3463e30c9a6bd5b740580720ae2bf6b3246..2eb5397d15732b224372c68d0b2b7167da9f2896 100644
> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> @@ -1429,17 +1429,52 @@ static void dpu_encoder_virt_atomic_disable(struct drm_encoder *drm_enc,
>  
>  static struct dpu_hw_intf *dpu_encoder_get_intf(const struct dpu_mdss_cfg *catalog,
>  		struct dpu_rm *dpu_rm,
> -		enum dpu_intf_type type, u32 controller_id)
> +		enum dpu_intf_type type, int enc_type, u32 id)
>  {
> -	int i = 0;
> +	int i = 0, cnt = 0;
> +	int controller_id = id >> 16;
> +	int stream_id = id & 0x0F;
>  
>  	if (type == INTF_WB)
>  		return NULL;
>  
> -	for (i = 0; i < catalog->intf_count; i++) {
> -		if (catalog->intf[i].type == type
> -		    && catalog->intf[i].controller_id == controller_id) {
> -			return dpu_rm_get_intf(dpu_rm, catalog->intf[i].id);
> +	if (enc_type == DRM_MODE_ENCODER_DPMST) {
> +		/* The intf order in dpu_intf_cfg matches the mapping in the DP HPG.
> +		 * example:
> +		 * DPU_8_4_0 - DP Controller intf to stream Mapping
> +		 *
> +		 * +-------------+----------+----------+----------+----------+
> +		 * | stream_id   |    0     |    1     |    2     |    3     |
> +		 * +-------------+----------+----------+----------+----------+
> +		 * | DP0         | INTF_0   | INTF_3   | INTF_6   | INTF_7   |
> +		 * | DP1         | INTF_4   | INTF_8   |          |          |
> +		 * +-------------+----------+----------+----------+----------+
> +		 *
> +		 * DPU_9_2_0 - DP Controller intf to stream Mapping
> +		 *
> +		 * +-------------+----------+----------+
> +		 * | Controller  |    0     |    1     |
> +		 * +-------------+----------+----------+
> +		 * | DP0         | INTF_0   | INTF_3   |
> +		 * | DP1         | INTF_4   | INTF_8   |
> +		 * | DP2         | INTF_6   | INTF_7   |
> +		 * +-------------+----------+----------+
> +		 */
> +		DPU_DEBUG("controller_id %d for stream_id = %d\n", controller_id, stream_id);
> +		for (i = 0; i < catalog->intf_count; i++) {
> +			if (catalog->intf[i].type == INTF_DP
> +			&& controller_id == catalog->intf[i].controller_id) {

&& should be on the previous line

> +				if (cnt == stream_id)

if (cnt++ == stream_id) return;

> +					return dpu_rm_get_intf(dpu_rm, catalog->intf[i].id);
> +				cnt++;
> +			}
> +		}

return NULL, drop else{}

> +	} else {
> +		for (i = 0; i < catalog->intf_count; i++) {
> +			if (catalog->intf[i].type == type
> +			&& catalog->intf[i].controller_id == controller_id) {
> +				return dpu_rm_get_intf(dpu_rm, catalog->intf[i].id);
> +			}
>  		}
>  	}
>  
> @@ -2670,7 +2705,9 @@ static int dpu_encoder_setup_display(struct dpu_encoder_virt *dpu_enc,
>  
>  		phys_params.hw_intf = dpu_encoder_get_intf(dpu_kms->catalog, &dpu_kms->rm,
>  							   disp_info->intf_type,
> -							   controller_id);
> +							   dpu_enc->base.encoder_type,
> +							   controller_id << 16
> +							   | disp_info->stream_id);

No need to, just pass whole disp_info pointer.

>  
>  		if (disp_info->intf_type == INTF_WB && controller_id < WB_MAX)
>  			phys_params.hw_wb = dpu_rm_get_wb(&dpu_kms->rm, controller_id);
> 
> -- 
> 2.34.1
> 

-- 
With best wishes
Dmitry