linux-kernel - [PATCH 34/45] drm/msm/dp: add support to re-use and clear the panel edid

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Message-ID: <20241205-dp_mst-v1-34-f8618d42a99a@quicinc.com>
Date: Thu, 5 Dec 2024 20:32:05 -0800
From: Abhinav Kumar <quic_abhinavk@...cinc.com>
To: Rob Clark <robdclark@...il.com>,
        Dmitry Baryshkov
	<dmitry.baryshkov@...aro.org>,
        Sean Paul <sean@...rly.run>,
        Marijn Suijten
	<marijn.suijten@...ainline.org>,
        David Airlie <airlied@...il.com>, "Simona
 Vetter" <simona@...ll.ch>,
        Stephen Boyd <swboyd@...omium.org>,
        "Chandan
 Uddaraju" <chandanu@...eaurora.org>,
        Guenter Roeck <groeck@...omium.org>,
        Kuogee Hsieh <quic_khsieh@...cinc.com>,
        Bjorn Andersson
	<andersson@...nel.org>,
        Konrad Dybcio <konradybcio@...nel.org>, Rob Herring
	<robh@...nel.org>,
        Krzysztof Kozlowski <krzk+dt@...nel.org>,
        Conor Dooley
	<conor+dt@...nel.org>
CC: Vara Reddy <quic_varar@...cinc.com>, Rob Clark <robdclark@...omium.org>,
        Tanmay Shah <tanmay@...eaurora.org>, <linux-arm-msm@...r.kernel.org>,
        <dri-devel@...ts.freedesktop.org>, <freedreno@...ts.freedesktop.org>,
        <linux-kernel@...r.kernel.org>, <devicetree@...r.kernel.org>,
        Jessica Zhang
	<quic_jesszhan@...cinc.com>,
        Laurent Pinchart
	<laurent.pinchart@...asonboard.com>,
        Abhinav Kumar
	<quic_abhinavk@...cinc.com>
Subject: [PATCH 34/45] drm/msm/dp: add support to re-use and clear the
 panel edid

During certain cases, the dp mst connector's panel edid can be
re-used such as getting multiple get_modes() without irq_hpd and
should be cleared in cases when the connector is destroyed or when
irq hpd is received. Add support to handle these cases for the
mst_connector's panel edid.

Signed-off-by: Abhinav Kumar <quic_abhinavk@...cinc.com>
---
 drivers/gpu/drm/msm/dp/dp_mst_drm.c | 39 +++++++++++++++++++++++++++++++++++++
 1 file changed, 39 insertions(+)

diff --git a/drivers/gpu/drm/msm/dp/dp_mst_drm.c b/drivers/gpu/drm/msm/dp/dp_mst_drm.c
index 2d92084586b466d4953429e8a6fbf766d081cb9f..15c61fd37c418889074222c0f576778adadf51c9 100644
--- a/drivers/gpu/drm/msm/dp/dp_mst_drm.c
+++ b/drivers/gpu/drm/msm/dp/dp_mst_drm.c
@@ -559,6 +559,34 @@ static struct msm_dp_mst_bridge_state *msm_dp_mst_br_priv_state(struct drm_atomi
 										&bridge->obj));
 }
 
+static void msm_dp_mst_clear_panel_edid(struct msm_dp *dp_display)
+{
+	struct msm_dp_mst *mst = dp_display->msm_dp_mst;
+	struct msm_dp_mst_connector *mst_conn;
+	struct msm_dp_panel *dp_panel;
+	struct msm_dp_mst_bridge *dp_bridge;
+	int i;
+
+	if (!dp_display) {
+		DRM_ERROR("invalid input\n");
+		return;
+	}
+
+	for (i = 0; i < mst->max_streams; i++) {
+		dp_bridge = &mst->mst_bridge[i];
+		mst_conn = to_msm_dp_mst_connector(dp_bridge->connector);
+		dp_panel = dp_bridge->msm_dp_panel;
+
+		if (!dp_panel || !mst_conn || !mst_conn->mst_port)
+			continue;
+
+		if (dp_panel->drm_edid) {
+			drm_edid_free(dp_panel->drm_edid);
+			dp_panel->drm_edid = NULL;
+		}
+	}
+}
+
 /* DP MST HPD IRQ callback */
 void msm_dp_mst_display_hpd_irq(struct msm_dp *dp_display)
 {
@@ -585,6 +613,9 @@ void msm_dp_mst_display_hpd_irq(struct msm_dp *dp_display)
 	if (handled) {
 		rc = drm_dp_dpcd_writeb(mst->dp_aux, esi_res, ack[1]);
 
+		if (ack[1] & DP_UP_REQ_MSG_RDY)
+			msm_dp_mst_clear_panel_edid(dp_display);
+
 		if (rc != 1)
 			DRM_ERROR("dpcd esi_res failed. rc=%d\n", rc);
 
@@ -620,6 +651,9 @@ static int msm_dp_mst_connector_get_modes(struct drm_connector *connector)
 	struct msm_dp_mst *mst = dp_display->msm_dp_mst;
 	struct msm_dp_panel *dp_panel = mst_conn->dp_panel;
 
+	if (dp_panel->drm_edid)
+		goto duplicate_edid;
+
 	drm_edid_free(dp_panel->drm_edid);
 
 	dp_panel->drm_edid = drm_dp_mst_edid_read(connector, &mst->mst_mgr, mst_conn->mst_port);
@@ -628,6 +662,7 @@ static int msm_dp_mst_connector_get_modes(struct drm_connector *connector)
 		return -EINVAL;
 	}
 
+duplicate_edid:
 	drm_edid_connector_update(connector, dp_panel->drm_edid);
 
 	return drm_edid_connector_add_modes(connector);
@@ -894,6 +929,10 @@ static int msm_dp_mst_connector_atomic_check(struct drm_connector *connector,
 static void dp_mst_connector_destroy(struct drm_connector *connector)
 {
 	struct msm_dp_mst_connector *mst_conn = to_msm_dp_mst_connector(connector);
+	struct msm_dp_panel *dp_panel = mst_conn->dp_panel;
+
+	drm_edid_free(dp_panel->drm_edid);
+	dp_panel->drm_edid = NULL;
 
 	drm_connector_cleanup(connector);
 	drm_dp_mst_put_port_malloc(mst_conn->mst_port);

-- 
2.34.1