[PATCH 5.4 023/138] drm/amd/display: Check DMCU Exists Before Loading

[Greg Kroah-Hartman]

From: Jerry (Fangzhi) Zuo <Jerry.Zuo@xxxxxxx>

[ Upstream commit 17bdb4a82fe5014c8aa5b2103c80c5729744a096 ]

Signed-off-by: Jerry (Fangzhi) Zuo <Jerry.Zuo@xxxxxxx>
Reviewed-by: Hersen Wu <hersenxs.wu@xxxxxxx>
Acked-by: Aurabindo Pillai <aurabindo.pillai@xxxxxxx>
Signed-off-by: Alex Deucher <alexander.deucher@xxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 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 4fad0b603b3ab..c7d8edf450d3c 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -928,9 +928,14 @@ 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