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

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Message-Id: <20211225063151.2110878-1-nikita.yoush@cogentembedded.com>
Date:   Sat, 25 Dec 2021 09:31:51 +0300
From:   Nikita Yushchenko <nikita.yoush@...entembedded.com>
To:     Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
        Maxime Ripard <mripard@...nel.org>,
        Thomas Zimmermann <tzimmermann@...e.de>,
        David Airlie <airlied@...ux.ie>,
        Daniel Vetter <daniel@...ll.ch>,
        Kieran Bingham <kieran.bingham+renesas@...asonboard.com>,
        Laurent Pinchart <laurent.pinchart+renesas@...asonboard.com>,
        Jacopo Mondi <jacopo+renesas@...ndi.org>
Cc:     dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org,
        Nikita Yushchenko <nikita.yoush@...entembedded.com>
Subject: [PATCH] drm/bridge_connector: enable HPD by default if supported

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>
---
 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 791379816837..4f20137ef21d 100644
--- a/drivers/gpu/drm/drm_bridge_connector.c
+++ b/drivers/gpu/drm/drm_bridge_connector.c
@@ -369,8 +369,10 @@ 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;
-- 
2.30.2