From d13b544c949e85e39f6c1c20485d8f37f5127e59 Mon Sep 17 00:00:00 2001
From: Sandor Yu <Sandor.yu@nxp.com>
Date: Fri, 20 Dec 2019 17:31:52 +0800
Subject: [PATCH] LF-568-2: drm: gpu: bridge: cdns: Add force mode set flag

In DRM framework, when hdmi/dp cable plugout/plugin in the same HDMI
sink, because the video mode is same, DRM will not call mode_set.
But for HDMI 2.0 sink the SCDC configurate will lost, and DP sink
linktraning status will lost too after cable plugout then plugin.

Currently, hdmi/dp driver will call mode_set function in HPD thread,
But the mode_set function is called out of DRM framework, and it have
chance to fail.
In the patch add force_mode_set flag, set the crtc_state->mode_changed
to force drm call mode_set when cable plugin.

Signed-off-by: Sandor Yu <Sandor.yu@nxp.com>
---
 drivers/gpu/drm/bridge/cadence/cdns-dp-core.c   |  5 +++++
 drivers/gpu/drm/bridge/cadence/cdns-hdmi-core.c | 12 ++++++++----
 drivers/gpu/drm/imx/cdn-mhdp-imxdrv.c           |  4 ++++
 include/drm/bridge/cdns-mhdp-common.h           |  1 +
 4 files changed, 18 insertions(+), 4 deletions(-)

--- a/drivers/gpu/drm/bridge/cadence/cdns-dp-core.c
+++ b/drivers/gpu/drm/bridge/cadence/cdns-dp-core.c
@@ -322,6 +322,9 @@ static void cdns_dp_bridge_mode_set(stru
 	mutex_lock(&mhdp->lock);
 	cdns_dp_mode_set(mhdp);
 	mutex_unlock(&mhdp->lock);
+
+	/* reset force mode set flag */
+	mhdp->force_mode_set = false;
 }
 
 static void cdn_dp_bridge_enable(struct drm_bridge *bridge)
@@ -375,6 +378,8 @@ static void hotplug_work_func(struct wor
 	} else if (connector->status == connector_status_disconnected) {
 		/* Cable Disconnedted  */
 		DRM_INFO("HDMI/DP Cable Plug Out\n");
+		/* force mode set for cable replugin to recovery DP video modes */
+		mhdp->force_mode_set = true;
 		enable_irq(mhdp->irq[IRQ_IN]);
 	}
 }
--- a/drivers/gpu/drm/bridge/cadence/cdns-hdmi-core.c
+++ b/drivers/gpu/drm/bridge/cadence/cdns-hdmi-core.c
@@ -178,6 +178,10 @@ void cdns_hdmi_mode_set(struct cdns_mhdp
 	struct drm_display_mode *mode = &mhdp->mode;
 	int ret;
 
+	/* video mode valid check */
+	if (mode->clock == 0 || mode->hdisplay == 0 ||  mode->vdisplay == 0)
+		return;
+
 	hdmi_lanes_config(mhdp);
 
 	cdns_mhdp_plat_call(mhdp, pclk_rate);
@@ -393,6 +397,8 @@ static void cdns_hdmi_bridge_mode_set(st
 	mutex_lock(&mhdp->lock);
 	cdns_hdmi_mode_set(mhdp);
 	mutex_unlock(&mhdp->lock);
+	/* reset force mode set flag */
+	mhdp->force_mode_set = false;
 }
 
 bool cdns_hdmi_bridge_mode_fixup(struct drm_bridge *bridge,
@@ -467,14 +473,12 @@ static void hotplug_work_func(struct wor
 
 	if (connector->status == connector_status_connected) {
 		DRM_INFO("HDMI Cable Plug In\n");
-		/* reset video mode after cable plugin */
-		mutex_lock(&mhdp->lock);
-		cdns_hdmi_mode_set(mhdp);
-		mutex_unlock(&mhdp->lock);
 		enable_irq(mhdp->irq[IRQ_OUT]);
 	} else if (connector->status == connector_status_disconnected) {
 		/* Cable Disconnedted  */
 		DRM_INFO("HDMI Cable Plug Out\n");
+		/* force mode set for cable replugin to recovery HDMI2.0 video modes */
+		mhdp->force_mode_set = true;
 		enable_irq(mhdp->irq[IRQ_IN]);
 	}
 }
--- a/drivers/gpu/drm/imx/cdn-mhdp-imxdrv.c
+++ b/drivers/gpu/drm/imx/cdn-mhdp-imxdrv.c
@@ -40,6 +40,10 @@ static int cdns_mhdp_imx_encoder_atomic_
 
 	if (mhdp->plat_data->video_format != 0)
 		imx_crtc_state->bus_format = mhdp->plat_data->video_format;
+
+	if (mhdp->force_mode_set)
+		crtc_state->mode_changed = true;
+
 	return 0;
 }
 
--- a/include/drm/bridge/cdns-mhdp-common.h
+++ b/include/drm/bridge/cdns-mhdp-common.h
@@ -684,6 +684,7 @@ struct cdns_mhdp_device {
 	bool link_up;
 	bool power_up;
 	bool plugged;
+	bool force_mode_set;
 	bool is_hpd;
 	bool is_ls1028a;
 	struct mutex lock;