linux-kernel - [PATCH 5.18 254/879] drm/bridge_connector: enable HPD by default if supported

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Date:   Tue,  7 Jun 2022 18:56:12 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org,
        Nikita Yushchenko <nikita.yoush@...entembedded.com>,
        Paul Cercueil <paul@...pouillou.net>,
        Kieran Bingham <kieran.bingham+renesas@...asonboard.com>,
        Laurent Pinchart <laurent.pinchart@...asonboard.com>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH 5.18 254/879] drm/bridge_connector: enable HPD by default if supported

From: Nikita Yushchenko <nikita.yoush@...entembedded.com>

[ Upstream commit 09077bc3116581f4d1cb961ec359ad56586e370b ]

Hotplug events reported by bridge drivers over drm_bridge_hpd_notify()
get ignored unless somebody calls drm_bridge_hpd_enable(). When the
connector for the bridge is bridge_connector, such a call is done from
drm_bridge_connector_enable_hpd().

However drm_bridge_connector_enable_hpd() is never called on init paths,
documentation suggests that it is intended for suspend/resume paths.

In result, once encoders are switched to bridge_connector,
bridge-detected HPD stops working.

This patch adds a call to that API on init path.

This fixes HDMI HPD with rcar-du + adv7513 case when adv7513 reports HPD
events via interrupts.

Fixes: c24110a8fd09 ("drm: rcar-du: Use drm_bridge_connector_init() helper")
Signed-off-by: Nikita Yushchenko <nikita.yoush@...entembedded.com>
Signed-off-by: Paul Cercueil <paul@...pouillou.net>
Tested-by: Kieran Bingham <kieran.bingham+renesas@...asonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham+renesas@...asonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@...asonboard.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211225063151.2110878-1-nikita.yoush@cogentembedded.com
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/gpu/drm/drm_bridge_connector.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/drm_bridge_connector.c b/drivers/gpu/drm/drm_bridge_connector.c
index 60923cdfe8e1..6b3dad03d77d 100644
--- a/drivers/gpu/drm/drm_bridge_connector.c
+++ b/drivers/gpu/drm/drm_bridge_connector.c
@@ -384,8 +384,10 @@ struct drm_connector *drm_bridge_connector_init(struct drm_device *drm,
 				    connector_type, ddc);
 	drm_connector_helper_add(connector, &drm_bridge_connector_helper_funcs);
 
-	if (bridge_connector->bridge_hpd)
+	if (bridge_connector->bridge_hpd) {
 		connector->polled = DRM_CONNECTOR_POLL_HPD;
+		drm_bridge_connector_enable_hpd(connector);
+	}
 	else if (bridge_connector->bridge_detect)
 		connector->polled = DRM_CONNECTOR_POLL_CONNECT
 				  | DRM_CONNECTOR_POLL_DISCONNECT;
-- 
2.35.1