[PATCH v2 20/38] drm/msm/dp: always program MST_FIFO_CONSTANT_FILL for MST

Yongxing Mou quic_yongmou at quicinc.com
Mon Jun 9 12:21:39 UTC 2025


From: Abhinav Kumar <quic_abhinavk at quicinc.com>

As required by the hardware programming guide, always program
the MST_FIFO_CONSTANT_FILL for MST use-cases.

Signed-off-by: Abhinav Kumar <quic_abhinavk at quicinc.com>
Signed-off-by: Yongxing Mou <quic_yongmou at quicinc.com>
---
 drivers/gpu/drm/msm/dp/dp_catalog.c | 16 ++++++++++++++++
 drivers/gpu/drm/msm/dp/dp_catalog.h |  2 ++
 drivers/gpu/drm/msm/dp/dp_ctrl.c    |  2 ++
 3 files changed, 20 insertions(+)

diff --git a/drivers/gpu/drm/msm/dp/dp_catalog.c b/drivers/gpu/drm/msm/dp/dp_catalog.c
index f2a5170723585ed6ddab2c12d2e5c5d6dee5eff5..b536530be160ed58ef17bf71385c3c4fc7617132 100644
--- a/drivers/gpu/drm/msm/dp/dp_catalog.c
+++ b/drivers/gpu/drm/msm/dp/dp_catalog.c
@@ -1011,6 +1011,22 @@ int msm_dp_catalog_panel_timing_cfg(struct msm_dp_catalog *msm_dp_catalog,
 	return 0;
 }
 
+int msm_dp_catalog_mst_async_fifo(struct msm_dp_catalog *msm_dp_catalog,
+				  enum msm_dp_stream_id stream_id, bool enable)
+{
+	struct msm_dp_catalog_private *catalog = container_of(msm_dp_catalog,
+							      struct msm_dp_catalog_private,
+							      msm_dp_catalog);
+
+	/* enable MST_FIFO_CONSTANT_FILL */
+	if (enable)
+		msm_dp_write_pn(catalog, stream_id, MMSS_DP_ASYNC_FIFO_CONFIG, 0x01);
+	else
+		msm_dp_write_pn(catalog, stream_id, MMSS_DP_ASYNC_FIFO_CONFIG, 0x00);
+
+	return 0;
+}
+
 static void msm_dp_catalog_panel_send_vsc_sdp(struct msm_dp_catalog *msm_dp_catalog,
 					      enum msm_dp_stream_id stream_id,
 					      struct dp_sdp *vsc_sdp)
diff --git a/drivers/gpu/drm/msm/dp/dp_catalog.h b/drivers/gpu/drm/msm/dp/dp_catalog.h
index a1ecab2f386f321ea9d176b3cf3f894a230c9085..7576458d4ef13def4f4d18073bd25ec0ffabde28 100644
--- a/drivers/gpu/drm/msm/dp/dp_catalog.h
+++ b/drivers/gpu/drm/msm/dp/dp_catalog.h
@@ -145,5 +145,7 @@ void msm_dp_catalog_mst_channel_alloc(struct msm_dp_catalog *dp_catalog,
 				      u32 tot_slot_cnt);
 void msm_dp_catalog_ctrl_update_rg(struct msm_dp_catalog *dp_catalog,
 				   enum msm_dp_stream_id stream_id, u32 x_int, u32 y_frac_enum);
+int msm_dp_catalog_mst_async_fifo(struct msm_dp_catalog *dp_catalog,
+				  enum msm_dp_stream_id stream_id, bool enable);
 
 #endif /* _DP_CATALOG_H_ */
diff --git a/drivers/gpu/drm/msm/dp/dp_ctrl.c b/drivers/gpu/drm/msm/dp/dp_ctrl.c
index a61514d4b5d42cd92eb13aa7d6759cdc9c0dda71..7056d5638829e8510054614b19afbcaf8aba55b5 100644
--- a/drivers/gpu/drm/msm/dp/dp_ctrl.c
+++ b/drivers/gpu/drm/msm/dp/dp_ctrl.c
@@ -236,6 +236,8 @@ static void msm_dp_ctrl_configure_source_params(struct msm_dp_ctrl_private *ctrl
 	cc = msm_dp_link_get_colorimetry_config(ctrl->link);
 	msm_dp_catalog_ctrl_config_misc(ctrl->catalog, msm_dp_panel->stream_id, cc, tb);
 	msm_dp_panel_timing_cfg(msm_dp_panel);
+
+	msm_dp_catalog_mst_async_fifo(ctrl->catalog, msm_dp_panel->stream_id, ctrl->mst_active);
 }
 
 /*

-- 
2.34.1



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