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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, "Jerry (Fangzhi) Zuo" <Jerry.Zuo@amd.com>,
        Hersen Wu <hersenxs.wu@amd.com>,
        Aurabindo Pillai <aurabindo.pillai@amd.com>,
        Alex Deucher <alexander.deucher@amd.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.7 022/179] drm/amd/display: Check DMCU Exists Before Loading
Date:   Mon, 27 Jul 2020 16:03:17 +0200
Message-Id: <20200727134933.751392896@linuxfoundation.org>
In-Reply-To: <20200727134932.659499757@linuxfoundation.org>
References: <20200727134932.659499757@linuxfoundation.org>
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From: Jerry (Fangzhi) Zuo <Jerry.Zuo@amd.com>

[ Upstream commit 17bdb4a82fe5014c8aa5b2103c80c5729744a096 ]

Signed-off-by: Jerry (Fangzhi) Zuo <Jerry.Zuo@amd.com>
Reviewed-by: Hersen Wu <hersenxs.wu@amd.com>
Acked-by: Aurabindo Pillai <aurabindo.pillai@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
index d06fa63801799..7da2a22dbde7e 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -1342,9 +1342,14 @@ static int dm_late_init(void *handle)
 	struct dmcu_iram_parameters params;
 	unsigned int linear_lut[16];
 	int i;
-	struct dmcu *dmcu = adev->dm.dc->res_pool->dmcu;
+	struct dmcu *dmcu = NULL;
 	bool ret;
 
+	if (!adev->dm.fw_dmcu)
+		return detect_mst_link_for_all_connectors(adev->ddev);
+
+	dmcu = adev->dm.dc->res_pool->dmcu;
+
 	for (i = 0; i < 16; i++)
 		linear_lut[i] = 0xFFFF * i / 15;
 
-- 
2.25.1