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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, Douglas Anderson <dianders@chromium.org>,
        Andrzej Hajda <a.hajda@samsung.com>,
        Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.10 301/593] drm/bridge: Fix the stop condition of drm_bridge_chain_pre_enable()
Date:   Mon, 12 Jul 2021 08:07:41 +0200
Message-Id: <20210712060917.979198453@linuxfoundation.org>
In-Reply-To: <20210712060843.180606720@linuxfoundation.org>
References: <20210712060843.180606720@linuxfoundation.org>
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From: Douglas Anderson <dianders@chromium.org>

[ Upstream commit bab5cca7e609952b069a550e39fe4893149fb658 ]

The drm_bridge_chain_pre_enable() is not the proper opposite of
drm_bridge_chain_post_disable(). It continues along the chain to
_before_ the starting bridge. Let's fix that.

Fixes: 05193dc38197 ("drm/bridge: Make the bridge chain a double-linked list")
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Andrzej Hajda <a.hajda@samsung.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210416153909.v4.1.If62a003f76a2bc4ccc6c53565becc05d2aad4430@changeid
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/gpu/drm/drm_bridge.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/drm_bridge.c b/drivers/gpu/drm/drm_bridge.c
index 64f0effb52ac..044acd07c153 100644
--- a/drivers/gpu/drm/drm_bridge.c
+++ b/drivers/gpu/drm/drm_bridge.c
@@ -522,6 +522,9 @@ void drm_bridge_chain_pre_enable(struct drm_bridge *bridge)
 	list_for_each_entry_reverse(iter, &encoder->bridge_chain, chain_node) {
 		if (iter->funcs->pre_enable)
 			iter->funcs->pre_enable(iter);
+
+		if (iter == bridge)
+			break;
 	}
 }
 EXPORT_SYMBOL(drm_bridge_chain_pre_enable);
-- 
2.30.2