linux-kernel - [PATCH v5 09/10] drm/vc4: hdmi: Enable the scrambler on reconnection

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Message-Id: <20210628124257.140453-10-maxime@cerno.tech>
Date:   Mon, 28 Jun 2021 14:42:56 +0200
From:   Maxime Ripard <maxime@...no.tech>
To:     Daniel Vetter <daniel.vetter@...el.com>,
        David Airlie <airlied@...ux.ie>,
        dri-devel@...ts.freedesktop.org,
        Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
        Thomas Zimmermann <tzimmermann@...e.de>,
        Maxime Ripard <maxime@...no.tech>
Cc:     Dave Stevenson <dave.stevenson@...pberrypi.com>,
        Phil Elwell <phil@...pberrypi.com>,
        Tim Gover <tim.gover@...pberrypi.com>,
        Dom Cobley <dom@...pberrypi.com>,
        linux-rpi-kernel@...ts.infradead.org,
        Maxime Ripard <mripard@...nel.org>,
        Emma Anholt <emma@...olt.net>,
        bcm-kernel-feedback-list@...adcom.com,
        Nicolas Saenz Julienne <nsaenz@...nel.org>,
        Eric Anholt <eric@...olt.net>, linux-kernel@...r.kernel.org
Subject: [PATCH v5 09/10] 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: c85695a2016e ("drm/vc4: hdmi: Enable the scrambler")
Signed-off-by: Maxime Ripard <maxime@...no.tech>
---
 drivers/gpu/drm/vc4/vc4_hdmi.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/vc4/vc4_hdmi.c b/drivers/gpu/drm/vc4/vc4_hdmi.c
index 46f656fd31b9..7efafc893920 100644
--- a/drivers/gpu/drm/vc4/vc4_hdmi.c
+++ b/drivers/gpu/drm/vc4/vc4_hdmi.c
@@ -161,6 +161,8 @@ 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)
 {
@@ -185,6 +187,8 @@ vc4_hdmi_connector_detect(struct drm_connector *connector, bool force)
 			}
 		}
 
+		vc4_hdmi_enable_scrambling(&vc4_hdmi->encoder.base.base);
+
 		return connector_status_connected;
 	}
 
@@ -535,9 +539,13 @@ static bool vc4_hdmi_supports_scrambling(struct drm_encoder *encoder,
 
 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;
 
-- 
2.31.1