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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Maxime Ripard <maxime@cerno.tech>,
        Dave Stevenson <dave.stevenson@raspberrypi.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.15 097/846] drm/vc4: hdmi: Enable the scrambler on reconnection
Date:   Mon, 24 Jan 2022 19:33:34 +0100
Message-Id: <20220124184104.336160681@linuxfoundation.org>
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From: Maxime Ripard <maxime@cerno.tech>

[ Upstream commit b7551457c5d0b3505b0be247d47919c1ee30506d ]

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: c85695a2016e ("drm/vc4: hdmi: Enable the scrambler")
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Reviewed-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
Link: https://lore.kernel.org/r/20211025152903.1088803-10-maxime@cerno.tech
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/gpu/drm/vc4/vc4_hdmi.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/vc4/vc4_hdmi.c b/drivers/gpu/drm/vc4/vc4_hdmi.c
index 49944644a9b36..e880bdd8dcfd2 100644
--- a/drivers/gpu/drm/vc4/vc4_hdmi.c
+++ b/drivers/gpu/drm/vc4/vc4_hdmi.c
@@ -162,6 +162,8 @@ static void vc4_hdmi_cec_update_clk_div(struct vc4_hdmi *vc4_hdmi)
 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)
 {
@@ -190,6 +192,7 @@ vc4_hdmi_connector_detect(struct drm_connector *connector, bool force)
 			}
 		}
 
+		vc4_hdmi_enable_scrambling(&vc4_hdmi->encoder.base.base);
 		pm_runtime_put(&vc4_hdmi->pdev->dev);
 		return connector_status_connected;
 	}
-- 
2.34.1