openwrt/target/linux/bcm27xx/patches-5.10/950-0655-drm-vc4-hdmi-Enable-the-scrambler-on-reconnection.patch

From 6dda05f181e44d54b97fff75162f63d0fb84b944 Mon Sep 17 00:00:00 2001
From: Maxime Ripard <maxime@cerno.tech>
Date: Fri, 25 Jun 2021 16:22:39 +0200
Subject: [PATCH] drm/vc4: hdmi: Enable the scrambler on reconnection

If we have a state already and disconnect/reconnect the display, the
SCDC messages won't be sent again since we didn't go through a disable /
enable cycle.

In order to fix this, let's call the vc4_hdmi_enable_scrambling function
in the detect callback if there is a mode and it needs the scrambler to
be enabled.

Fixes: 74465b84fa27 ("drm/vc4: hdmi: Enable the scrambler")
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
---
 drivers/gpu/drm/vc4/vc4_hdmi.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

--- a/drivers/gpu/drm/vc4/vc4_hdmi.c
+++ b/drivers/gpu/drm/vc4/vc4_hdmi.c
@@ -170,6 +170,8 @@ static void vc4_hdmi_cec_update_clk_div(
 static void vc4_hdmi_cec_update_clk_div(struct vc4_hdmi *vc4_hdmi) {}
 #endif
 
+static void vc4_hdmi_enable_scrambling(struct drm_encoder *encoder);
+
 static enum drm_connector_status
 vc4_hdmi_connector_detect(struct drm_connector *connector, bool force)
 {
@@ -199,6 +201,8 @@ vc4_hdmi_connector_detect(struct drm_con
 			}
 		}
 
+		vc4_hdmi_enable_scrambling(&vc4_hdmi->encoder.base.base);
+
 		pm_runtime_put(&vc4_hdmi->pdev->dev);
 		return connector_status_connected;
 	}
@@ -545,9 +549,13 @@ static bool vc4_hdmi_supports_scrambling
 
 static void vc4_hdmi_enable_scrambling(struct drm_encoder *encoder)
 {
-	struct drm_display_mode *mode = &encoder->crtc->state->adjusted_mode;
+	struct drm_display_mode *mode;
 	struct vc4_hdmi *vc4_hdmi = encoder_to_vc4_hdmi(encoder);
 
+	if (!encoder->crtc || !encoder->crtc->state)
+		return;
+
+	mode = &encoder->crtc->state->adjusted_mode;
 	if (!vc4_hdmi_supports_scrambling(encoder, mode))
 		return;