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From:   Linus Walleij <linus.walleij@linaro.org>
Date:   Tue, 28 Nov 2023 00:10:21 +0100
Subject: [PATCH 3/3] Revert "drm/bridge: panel: Add a device link between
 drm device and panel device"
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Message-Id: <20231128-revert-panel-fix-v1-3-69bb05048dae@linaro.org>
References: <20231128-revert-panel-fix-v1-0-69bb05048dae@linaro.org>
In-Reply-To: <20231128-revert-panel-fix-v1-0-69bb05048dae@linaro.org>
To:     Liu Ying <victor.liu@nxp.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        "Rafael J. Wysocki" <rafael@kernel.org>,
        Andrzej Hajda <andrzej.hajda@intel.com>,
        Neil Armstrong <neil.armstrong@linaro.org>,
        Robert Foss <rfoss@kernel.org>,
        Laurent Pinchart <Laurent.pinchart@ideasonboard.com>,
        Jonas Karlman <jonas@kwiboo.se>,
        Jernej Skrabec <jernej.skrabec@gmail.com>,
        Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
        Maxime Ripard <mripard@kernel.org>,
        Thomas Zimmermann <tzimmermann@suse.de>,
        David Airlie <airlied@gmail.com>,
        Daniel Vetter <daniel@ffwll.ch>
Cc:     linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org,
        Linus Walleij <linus.walleij@linaro.org>
Precedence: bulk

This reverts commit 199cf07ebd2b0d41185ac79b895547d45610b681.

This patch creates bugs on devices where the DRM device is
the ancestor of the panel devices.

Attempts to fix this have failed because it leads to using
device core functionality which is questionable.

Reported-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/lkml/CACRpkdaGzXD6HbiX7mVUNJAJtMEPG00Pp6+nJ1P0JrfJ-ArMvQ@mail.gmail.com/T/
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
---
 drivers/gpu/drm/bridge/panel.c | 17 -----------------
 1 file changed, 17 deletions(-)

diff --git a/drivers/gpu/drm/bridge/panel.c b/drivers/gpu/drm/bridge/panel.c
index e48823a4f1ed..7f41525f7a6e 100644
--- a/drivers/gpu/drm/bridge/panel.c
+++ b/drivers/gpu/drm/bridge/panel.c
@@ -4,8 +4,6 @@
  * Copyright (C) 2017 Broadcom
  */
 
-#include <linux/device.h>
-
 #include <drm/drm_atomic_helper.h>
 #include <drm/drm_bridge.h>
 #include <drm/drm_connector.h>
@@ -21,7 +19,6 @@ struct panel_bridge {
 	struct drm_bridge bridge;
 	struct drm_connector connector;
 	struct drm_panel *panel;
-	struct device_link *link;
 	u32 connector_type;
 };
 
@@ -63,24 +60,13 @@ static int panel_bridge_attach(struct drm_bridge *bridge,
 {
 	struct panel_bridge *panel_bridge = drm_bridge_to_panel_bridge(bridge);
 	struct drm_connector *connector = &panel_bridge->connector;
-	struct drm_panel *panel = panel_bridge->panel;
-	struct drm_device *drm_dev = bridge->dev;
 	int ret;
 
-	panel_bridge->link = device_link_add(drm_dev->dev, panel->dev,
-					     DL_FLAG_STATELESS);
-	if (!panel_bridge->link) {
-		DRM_ERROR("Failed to add device link between %s and %s\n",
-			  dev_name(drm_dev->dev), dev_name(panel->dev));
-		return -EINVAL;
-	}
-
 	if (flags & DRM_BRIDGE_ATTACH_NO_CONNECTOR)
 		return 0;
 
 	if (!bridge->encoder) {
 		DRM_ERROR("Missing encoder\n");
-		device_link_del(panel_bridge->link);
 		return -ENODEV;
 	}
 
@@ -92,7 +78,6 @@ static int panel_bridge_attach(struct drm_bridge *bridge,
 				 panel_bridge->connector_type);
 	if (ret) {
 		DRM_ERROR("Failed to initialize connector\n");
-		device_link_del(panel_bridge->link);
 		return ret;
 	}
 
@@ -115,8 +100,6 @@ static void panel_bridge_detach(struct drm_bridge *bridge)
 	struct panel_bridge *panel_bridge = drm_bridge_to_panel_bridge(bridge);
 	struct drm_connector *connector = &panel_bridge->connector;
 
-	device_link_del(panel_bridge->link);
-
 	/*
 	 * Cleanup the connector if we know it was initialized.
 	 *

-- 
2.41.0