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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, Aric Cyr <aric.cyr@amd.com>,
        Harry Wentland <harry.wentland@amd.com>,
        Bhawanpreet Lakha <Bhawanpreet.Lakha@amd.com>,
        Alex Deucher <alexander.deucher@amd.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.4 043/152] drm/amd/display: Check engine is not NULL before acquiring
Date:   Tue,  3 Mar 2020 18:42:21 +0100
Message-Id: <20200303174307.275923002@linuxfoundation.org>
In-Reply-To: <20200303174302.523080016@linuxfoundation.org>
References: <20200303174302.523080016@linuxfoundation.org>
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From: Aric Cyr <aric.cyr@amd.com>

[ Upstream commit 2b63d0ec0daf79ba503fa8bfa25e07dc3da274f3 ]

[Why]
Engine can be NULL in some cases, so we must not acquire it.

[How]
Check for NULL engine before acquiring.

Signed-off-by: Aric Cyr <aric.cyr@amd.com>
Reviewed-by: Harry Wentland <harry.wentland@amd.com>
Acked-by: Bhawanpreet Lakha <Bhawanpreet.Lakha@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/gpu/drm/amd/display/dc/dce/dce_aux.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/display/dc/dce/dce_aux.c b/drivers/gpu/drm/amd/display/dc/dce/dce_aux.c
index c3f9f4185ce8d..cf877238fff9d 100644
--- a/drivers/gpu/drm/amd/display/dc/dce/dce_aux.c
+++ b/drivers/gpu/drm/amd/display/dc/dce/dce_aux.c
@@ -386,7 +386,7 @@ static bool acquire(
 {
 	enum gpio_result result;
 
-	if (!is_engine_available(engine))
+	if ((engine == NULL) || !is_engine_available(engine))
 		return false;
 
 	result = dal_ddc_open(ddc, GPIO_MODE_HARDWARE,
-- 
2.20.1