[PATCH v3 34/38] drm/msm: initialize DRM MST encoders for DP controllers

[Dmitry Baryshkov]

On Mon, Aug 25, 2025 at 10:16:20PM +0800, Yongxing Mou wrote:
> From: Abhinav Kumar <quic_abhinavk at quicinc.com>
> 
> Initialize a DPMST encoder for each  MST capable DP controller
> and the number of encoders it supports depends on the number
> of streams it supports.
> 
> Signed-off-by: Abhinav Kumar <quic_abhinavk at quicinc.com>
> Signed-off-by: Yongxing Mou <yongxing.mou at oss.qualcomm.com>
> ---
>  drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.h |  2 ++
>  drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c     | 23 ++++++++++++++++++++++-
>  drivers/gpu/drm/msm/dp/dp_mst_drm.h         |  2 --
>  drivers/gpu/drm/msm/msm_drv.h               | 13 +++++++++++++
>  4 files changed, 37 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.h b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.h
> index ca1ca2e51d7ead0eb34b27f3168e6bb06a71a11a..2eb4c39b111c1d8622e09e78ffafef017e28bbf6 100644
> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.h
> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.h
> @@ -28,6 +28,7 @@
>   * @h_tile_instance:    Controller instance used per tile. Number of elements is
>   *                      based on num_of_h_tiles
>   * @is_cmd_mode		Boolean to indicate if the CMD mode is requested
> + * @stream_id		stream id for which the interface needs to be acquired
>   * @vsync_source:	Source of the TE signal for DSI CMD devices
>   */
>  struct msm_display_info {
> @@ -35,6 +36,7 @@ struct msm_display_info {
>  	uint32_t num_of_h_tiles;
>  	uint32_t h_tile_instance[MAX_H_TILES_PER_DISPLAY];
>  	bool is_cmd_mode;
> +	int stream_id;
>  	enum dpu_vsync_source vsync_source;
>  };
>  
> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c
> index 12dcb32b472497f9e59619db4e810abfbf610c7c..0b9d9207f4f69e0d0725ff265c624828b5816a8b 100644
> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c
> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c
> @@ -653,7 +653,8 @@ static int _dpu_kms_initialize_displayport(struct drm_device *dev,
>  	struct msm_display_info info;
>  	bool yuv_supported;
>  	int rc;
> -	int i;
> +	int i, stream_id;
> +	int stream_cnt;
>  
>  	for (i = 0; i < ARRAY_SIZE(priv->kms->dp); i++) {
>  		if (!priv->kms->dp[i])
> @@ -676,6 +677,26 @@ static int _dpu_kms_initialize_displayport(struct drm_device *dev,
>  			DPU_ERROR("modeset_init failed for DP, rc = %d\n", rc);
>  			return rc;
>  		}
> +
> +		stream_cnt = msm_dp_get_mst_max_stream(priv->kms->dp[i]);
> +
> +		if (stream_cnt > 1) {
> +			for (stream_id = 0; stream_id < stream_cnt; stream_id++) {
> +				info.stream_id = stream_id;
> +				encoder = dpu_encoder_init(dev, DRM_MODE_ENCODER_DPMST, &info);
> +				if (IS_ERR(encoder)) {
> +					DPU_ERROR("encoder init failed for dp mst display\n");
> +					return PTR_ERR(encoder);
> +				}
> +
> +				rc = msm_dp_mst_drm_bridge_init(priv->kms->dp[i], encoder);

This is an implementation detail. We should be asking to init MST, which
might or might not be a bridge.

> +				if (rc) {
> +					DPU_ERROR("dp mst bridge %d init failed, %d\n",

DP, MST, no 'bridge'.

> +						  stream_id, rc);
> +					continue;
> +				}
> +			}
> +		}
>  	}
>  
>  	return 0;
> diff --git a/drivers/gpu/drm/msm/dp/dp_mst_drm.h b/drivers/gpu/drm/msm/dp/dp_mst_drm.h
> index 8fe6cbbe741da4abb232256b3a15ba6b16ca4f3e..d73e3f908439094532e88945ed4d41ed092051c9 100644
> --- a/drivers/gpu/drm/msm/dp/dp_mst_drm.h
> +++ b/drivers/gpu/drm/msm/dp/dp_mst_drm.h
> @@ -82,8 +82,6 @@ struct msm_dp_mst_connector {
>  	struct msm_dp_panel *dp_panel;
>  };
>  

> -int msm_dp_mst_drm_bridge_init(struct msm_dp *dp, struct drm_encoder *encoder);
> -

Squash this and the next chunks to the corresponding patches.

>  int msm_dp_mst_init(struct msm_dp *dp_display, u32 max_streams, struct drm_dp_aux *drm_aux);
>  
>  void msm_dp_mst_display_hpd_irq(struct msm_dp *dp_display);
> diff --git a/drivers/gpu/drm/msm/msm_drv.h b/drivers/gpu/drm/msm/msm_drv.h
> index 985db9febd98e35dfed51d39dac1a522abe5a351..3e64ec7b7dbe1d1107e85def9aa80277131f40bf 100644
> --- a/drivers/gpu/drm/msm/msm_drv.h
> +++ b/drivers/gpu/drm/msm/msm_drv.h
> @@ -363,6 +363,9 @@ bool msm_dp_needs_periph_flush(const struct msm_dp *dp_display,
>  			       const struct drm_display_mode *mode);
>  bool msm_dp_wide_bus_available(const struct msm_dp *dp_display);
>  
> +int msm_dp_get_mst_max_stream(struct msm_dp *dp_display);
> +int msm_dp_mst_drm_bridge_init(struct msm_dp *dp_display, struct drm_encoder *encoder);
> +
>  #else
>  static inline int __init msm_dp_register(void)
>  {
> @@ -379,6 +382,16 @@ static inline int msm_dp_modeset_init(struct msm_dp *dp_display,
>  	return -EINVAL;
>  }
>  
> +static inline int msm_dp_get_mst_max_stream(struct msm_dp *dp_display)
> +{
> +	return -EINVAL;
> +}
> +
> +static inline int msm_dp_mst_drm_bridge_init(struct msm_dp *dp_display, struct drm_encoder *encoder)
> +{
> +	return -EINVAL;
> +}
> +
>  static inline void msm_dp_snapshot(struct msm_disp_state *disp_state, struct msm_dp *dp_display)
>  {
>  }
> 
> -- 
> 2.34.1
> 

-- 
With best wishes
Dmitry