From: Harry Wentland <harry.wentland@amd.com>
Date: Tue, 9 May 2017 10:41:42 -0400
Subject: drm/amd/display: Keep DVI_SINGLE_LINK signal if low clk
Git-commit: 56dcade33fd3c1681a43ebc250523249be3adbb0
Patch-mainline: v4.15-rc1
References: FATE#326289 FATE#326079 FATE#326049 FATE#322398 FATE#326166

If user is using DVI->HDMI dongle dual link signal might pose a
problem. Keep single link signal type if clk is lower than
max tmds clk.

Signed-off-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Acked-by: Petr Tesarik <ptesarik@suse.com>
---
 drivers/gpu/drm/amd/display/dc/core/dc_resource.c |    9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

--- a/drivers/gpu/drm/amd/display/dc/core/dc_resource.c
+++ b/drivers/gpu/drm/amd/display/dc/core/dc_resource.c
@@ -1283,9 +1283,12 @@ static void update_stream_signal(struct
 		stream->signal = stream->public.output_signal;
 	}
 
-	if (stream->signal == SIGNAL_TYPE_DVI_SINGLE_LINK &&
-		stream->public.timing.pix_clk_khz > TMDS_MAX_PIXEL_CLOCK_IN_KHZ)
-		stream->signal = SIGNAL_TYPE_DVI_DUAL_LINK;
+	if (dc_is_dvi_signal(stream->signal)) {
+		if (stream->public.timing.pix_clk_khz > TMDS_MAX_PIXEL_CLOCK_IN_KHZ)
+			stream->signal = SIGNAL_TYPE_DVI_DUAL_LINK;
+		else
+			stream->signal = SIGNAL_TYPE_DVI_SINGLE_LINK;
+	}
 }
 
 bool resource_is_stream_unchanged(