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From: Yongxing Mou <yongxing.mou@oss.qualcomm.com>
To: Rob Clark <robin.clark@oss.qualcomm.com>,
	Dmitry Baryshkov <lumag@kernel.org>,
	Abhinav Kumar <abhinav.kumar@linux.dev>,
	Sean Paul <sean@poorly.run>,
	Marijn Suijten <marijn.suijten@somainline.org>,
	David Airlie <airlied@gmail.com>, Simona Vetter <simona@ffwll.ch>,
	Jessica Zhang <jesszhan0024@gmail.com>
Cc: linux-arm-msm@vger.kernel.org, dri-devel@lists.freedesktop.org,
	freedreno@lists.freedesktop.org, linux-kernel@vger.kernel.org,
	Yongxing Mou <yongxing.mou@oss.qualcomm.com>,
	Abhinav Kumar <quic_abhinavk@quicinc.com>,
	Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Subject: [PATCH v8 05/29] drm/msm/dp: always program MST_FIFO_CONSTANT_FILL for MST use cases
Date: Tue, 10 Nov 2026 12:54:26 +0800	[thread overview]
Message-ID: <20261110-msm-dp-mst-v8-5-d040fb33db5f@oss.qualcomm.com> (raw)
In-Reply-To: <20261110-msm-dp-mst-v8-0-d040fb33db5f@oss.qualcomm.com>

From: Abhinav Kumar <quic_abhinavk@quicinc.com>

As per the hardware programming guide, MST_FIFO_CONSTANT_FILL must
always be programmed when operating in MST mode. Ensure the register
is configured accordingly.

Signed-off-by: Abhinav Kumar <quic_abhinavk@quicinc.com>
Signed-off-by: Yongxing Mou <yongxing.mou@oss.qualcomm.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
---
 drivers/gpu/drm/msm/dp/dp_ctrl.c  |  2 ++
 drivers/gpu/drm/msm/dp/dp_panel.c | 12 ++++++++++++
 drivers/gpu/drm/msm/dp/dp_panel.h |  2 ++
 3 files changed, 16 insertions(+)

diff --git a/drivers/gpu/drm/msm/dp/dp_ctrl.c b/drivers/gpu/drm/msm/dp/dp_ctrl.c
index a7cd3c87cd7e3..249c818fe79c5 100644
--- a/drivers/gpu/drm/msm/dp/dp_ctrl.c
+++ b/drivers/gpu/drm/msm/dp/dp_ctrl.c
@@ -584,6 +584,8 @@ static void msm_dp_ctrl_configure_source_params(struct msm_dp_ctrl_private *ctrl
 	msm_dp_ctrl_config_misc1_misc0(ctrl, panel);
 
 	msm_dp_panel_timing_cfg(panel, ctrl->msm_dp_ctrl.wide_bus_en);
+
+	msm_dp_panel_mst_async_fifo(panel, ctrl->mst_mode);
 }
 
 /*
diff --git a/drivers/gpu/drm/msm/dp/dp_panel.c b/drivers/gpu/drm/msm/dp/dp_panel.c
index d3468b73fdc32..bc7bad5ca3b18 100644
--- a/drivers/gpu/drm/msm/dp/dp_panel.c
+++ b/drivers/gpu/drm/msm/dp/dp_panel.c
@@ -741,6 +741,18 @@ int msm_dp_panel_timing_cfg(struct msm_dp_panel *msm_dp_panel, bool wide_bus_en)
 	return 0;
 }
 
+void msm_dp_panel_mst_async_fifo(struct msm_dp_panel *msm_dp_panel, bool mst_en)
+{
+	struct msm_dp_panel_private *panel;
+
+	panel = container_of(msm_dp_panel, struct msm_dp_panel_private, msm_dp_panel);
+
+	if (mst_en)
+		msm_dp_write_pn(panel, MMSS_DP_ASYNC_FIFO_CONFIG, 0x01);
+	else
+		msm_dp_write_pn(panel, MMSS_DP_ASYNC_FIFO_CONFIG, 0x00);
+}
+
 int msm_dp_panel_init_panel_info(struct msm_dp_panel *msm_dp_panel,
 				 const struct drm_display_mode *adjusted_mode,
 				 u32 bpp)
diff --git a/drivers/gpu/drm/msm/dp/dp_panel.h b/drivers/gpu/drm/msm/dp/dp_panel.h
index dc046fec24fc7..04938b9d2091f 100644
--- a/drivers/gpu/drm/msm/dp/dp_panel.h
+++ b/drivers/gpu/drm/msm/dp/dp_panel.h
@@ -72,6 +72,8 @@ void msm_dp_panel_clear_dsc_dto(struct msm_dp_panel *msm_dp_panel);
 void msm_dp_panel_enable_vsc_sdp(struct msm_dp_panel *msm_dp_panel, struct dp_sdp *vsc_sdp);
 void msm_dp_panel_disable_vsc_sdp(struct msm_dp_panel *msm_dp_panel);
 
+void msm_dp_panel_mst_async_fifo(struct msm_dp_panel *msm_dp_panel, bool mst_en);
+
 /**
  * is_link_rate_valid() - validates the link rate
  * @bw_code: link rate requested by the sink

-- 
2.43.0


  parent reply	other threads:[~2026-11-10  4:55 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-11-10  4:54 [PATCH v8 00/29] drm/msm/dp: Add MST support for MSM chipsets Yongxing Mou
2026-11-10  4:54 ` [PATCH v8 01/29] drm/msm/dp: skip sink requests while the mainlink clocks are off Yongxing Mou
2026-11-10  4:54 ` [PATCH v8 02/29] drm/msm/dp: add support to send ACT packets for MST Yongxing Mou
2026-11-10  4:54 ` [PATCH v8 03/29] drm/msm/dp: add support to enable MST in mainlink control Yongxing Mou
2026-11-10  4:54 ` [PATCH v8 04/29] drm/msm/dp: no need to update tu calculation for mst Yongxing Mou
2026-11-10  4:54 ` Yongxing Mou [this message]
2026-11-10  4:54 ` [PATCH v8 06/29] drm/msm/dp: add support for sending VCPF packets in DP controller Yongxing Mou
2026-11-10  4:54 ` [PATCH v8 07/29] drm/msm/dp: add support for MST channel slot allocation Yongxing Mou
2026-11-10  4:54 ` [PATCH v8 08/29] drm/msm/dp: replace power_on with active_stream_mask Yongxing Mou
2026-11-10  4:54 ` [PATCH v8 09/29] drm/msm/dp: factor out _helper variants of bridge ops accepting a panel Yongxing Mou
2026-11-10  4:54 ` [PATCH v8 10/29] drm/msm/dp: add link_ready to manage link-level operations Yongxing Mou
2026-11-10  4:54 ` [PATCH v8 11/29] drm/msm/dp: add msm_dp_display_get_panel() to initialize DP panel Yongxing Mou
2026-11-10  4:54 ` [PATCH v8 12/29] drm/msm/dp: introduce dp_mst_drm module Yongxing Mou
2026-11-10  4:54 ` [PATCH v8 13/29] drm/msm/dp: add MST connector creation and topology callbacks Yongxing Mou
2026-11-10  4:54 ` [PATCH v8 14/29] drm/msm/dpu: pass msm_display_info to dpu_encoder_get_intf() Yongxing Mou
2026-11-10  4:54 ` [PATCH v8 15/29] drm/msm/dpu: use stream_id to select MST interfaces Yongxing Mou
2026-11-10  4:54 ` [PATCH v8 16/29] drm/msm/dpu: add per-stream MST encoders Yongxing Mou
2026-11-10  4:54 ` [PATCH v8 17/29] drm/msm/dp: move link capabilities to dp_link Yongxing Mou
2026-11-10  4:54 ` [PATCH v8 18/29] drm/msm/dp: add atomic stream handling for MST Yongxing Mou
2026-11-10  4:54 ` [PATCH v8 19/29] drm/bridge_connector: suppress hotplug for IRQ_HPD without status changes Yongxing Mou
2026-11-10  4:54 ` [PATCH v8 20/29] drm/bridge_connector: avoid detect-based HPD notifications for DisplayPort Yongxing Mou
2026-11-10  4:54 ` [PATCH v8 21/29] drm/msm/dp: add HPD callback for dp MST Yongxing Mou
2026-11-10  4:54 ` [PATCH v8 22/29] drm/msm/dp: wire MST helpers into atomic check and commit paths Yongxing Mou
2026-11-10  4:54 ` [PATCH v8 23/29] drm/msm/dp: mark the SST bridge disconnected when mst is active Yongxing Mou
2026-11-10  4:54 ` [PATCH v8 24/29] drm/msm/dp: enable MST on capable sinks Yongxing Mou
2026-11-10  4:54 ` [PATCH v8 25/29] drm/msm/dp: mark the SST bridge disconnected when an MST-capable sink is present Yongxing Mou
2026-11-10  4:54 ` [PATCH v8 26/29] drm/msm/dp: wake threaded handler for HPD IRQs Yongxing Mou
2026-11-10  4:54 ` [PATCH v8 27/29] drm/msm/dp: ignore IRQ HPD latched together with an unplug Yongxing Mou
2026-11-10  4:54 ` [PATCH v8 28/29] drm/msm/dp: select MST stream bpp during atomic check Yongxing Mou
2026-11-10  4:54 ` [PATCH v8 29/29] soc: qcom: pmic-glink-altmode: skip retimer reset on DP IRQ Yongxing Mou

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