Re: [PATCH v2 33/38] drm/msm: initialize DRM MST encoders for DP controllers

[Yongxing Mou]

On 2025/6/9 22:17, Dmitry Baryshkov wrote:
On Mon, Jun 09, 2025 at 08:21:52PM +0800, Yongxing Mou wrote:
From: Abhinav Kumar <quic_abhin...@quicinc.com>

Initiliaze 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_abhin...@quicinc.com>
Signed-off-by: Yongxing Mou <quic_yong...@quicinc.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_display.c         | 14 ++++++++++++++

Please don't mix DP and DPU changes in a single patch.

Got it, thanks, will separate it.
  drivers/gpu/drm/msm/msm_drv.h               | 13 +++++++++++++
  4 files changed, 51 insertions(+), 1 deletion(-)

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 
1fd82b6747e9058ce11dc2620729921492d5ebdd..45fedf7e74e9c6dfed4bde57eb675e3dd1762fc7
 100644
--- a/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c
+++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c
@@ -652,7 +652,8 @@ 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->dp); i++) {
                if (!priv->dp[i])
@@ -675,6 +676,26 @@ 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->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_bridge_init(priv->dp[i], 
encoder);
+                               if (rc) {
+                                       DPU_ERROR("dp mst bridge %d init failed, 
%d\n",
+                                                 stream_id, rc);
+                                       continue;
+                               }
+                       }
+               }
        }
  
  	return 0;
diff --git a/drivers/gpu/drm/msm/dp/dp_display.c 
b/drivers/gpu/drm/msm/dp/dp_display.c
index 
9dbcf4553cad70c9e3722160a87403fc815765d7..ab1ad0cb6427eb4f86ee8ac6c76788b1a78892a8
 100644
--- a/drivers/gpu/drm/msm/dp/dp_display.c
+++ b/drivers/gpu/drm/msm/dp/dp_display.c
@@ -1417,6 +1417,20 @@ static int msm_dp_display_get_connector_type(struct 
platform_device *pdev,
        return connector_type;
  }
  
+int msm_dp_get_mst_max_stream(struct msm_dp *dp_display)
+{
+       struct msm_dp_display_private *dp_priv;
+
+       dp_priv = container_of(dp_display, struct msm_dp_display_private, 
msm_dp_display);
+
+       return dp_priv->max_stream;
+}
+
+int msm_dp_mst_bridge_init(struct msm_dp *dp_display, struct drm_encoder 
*encoder)
+{
+       return msm_dp_mst_drm_bridge_init(dp_display, encoder);

What's the point in this oneliner?

Emm, here we consider declaring the msm_dp_mst_drm_bridge_init() in 
msm_drv.h and drop the one-line wrapper.


+}
+
  static int msm_dp_display_probe(struct platform_device *pdev)
  {
        int rc = 0;
diff --git a/drivers/gpu/drm/msm/msm_drv.h b/drivers/gpu/drm/msm/msm_drv.h
index 
a65077855201746c37ee742364b61116565f3794..dd403107b640ee5ef333d2773b52e38e3869155f
 100644
--- a/drivers/gpu/drm/msm/msm_drv.h
+++ b/drivers/gpu/drm/msm/msm_drv.h
@@ -372,6 +372,9 @@ 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_bridge_init(struct msm_dp *dp_display, struct drm_encoder 
*encoder);
+
  #else
  static inline int __init msm_dp_register(void)
  {
@@ -388,6 +391,16 @@ 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_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