From 32d6e0da0b45ddef32092975b37a8b3f322587e8 Mon Sep 17 00:00:00 2001
From: Nikola Cornij <nikola.cornij@amd.com>
Date: Sun, 5 Apr 2020 16:40:42 -0400
Subject: drm/amd/display: Program DSC before enabling link
Git-commit: c06a545ae531bd8f791dc41b787822512eb65c5d
Patch-mainline: v5.8-rc1
References: jsc#SLE-12680, jsc#SLE-12880, jsc#SLE-12882, jsc#SLE-12883, jsc#SLE-13496, jsc#SLE-15322

[why]
Link or DIG BE can't be exposed to a higher stream bandwidth than they
can handle. When DSC is required to fit the stream into the link
bandwidth, DSC has to be programmed before the link is enabled to ensure
this. Without it, intermittent issues such as black screen after S3 or a
hot-plug can be seen with DSC timings like 4k144Hz or 8k60Hz.

[how]
Move DSC programming from before enabling stream to before enabling link

Signed-off-by: Nikola Cornij <nikola.cornij@amd.com>
Reviewed-by: Jun Lei <Jun.Lei@amd.com>
Acked-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Patrik Jakobsson <pjakobsson@suse.de>
---
 drivers/gpu/drm/amd/display/dc/core/dc_link.c | 17 ++++++++++++-----
 1 file changed, 12 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/amd/display/dc/core/dc_link.c b/drivers/gpu/drm/amd/display/dc/core/dc_link.c
index 1e64c0135a2c..b66d416ed167 100644
--- a/drivers/gpu/drm/amd/display/dc/core/dc_link.c
+++ b/drivers/gpu/drm/amd/display/dc/core/dc_link.c
@@ -3035,6 +3035,18 @@ void core_link_enable_stream(
 		if (pipe_ctx->stream->dpms_off)
 			return;
 
+		/* Have to setup DSC before DIG FE and BE are connected (which happens before the
+		 * link training). This is to make sure the bandwidth sent to DIG BE won't be
+		 * bigger than what the link and/or DIG BE can handle. VBID[6]/CompressedStream_flag
+		 * will be automatically set at a later time when the video is enabled
+		 * (DP_VID_STREAM_EN = 1).
+		 */
+		if (pipe_ctx->stream->timing.flags.DSC) {
+			if (dc_is_dp_signal(pipe_ctx->stream->signal) ||
+					dc_is_virtual_signal(pipe_ctx->stream->signal))
+				dp_set_dsc_enable(pipe_ctx, true);
+		}
+
 		status = enable_link(state, pipe_ctx);
 
 		if (status != DC_OK) {
@@ -3062,11 +3074,6 @@ void core_link_enable_stream(
 					CONTROLLER_DP_TEST_PATTERN_VIDEOMODE,
 					COLOR_DEPTH_UNDEFINED);
 
-		if (pipe_ctx->stream->timing.flags.DSC) {
-			if (dc_is_dp_signal(pipe_ctx->stream->signal) ||
-					dc_is_virtual_signal(pipe_ctx->stream->signal))
-				dp_set_dsc_enable(pipe_ctx, true);
-		}
 		dc->hwss.enable_stream(pipe_ctx);
 
 		/* Set DPS PPS SDP (AKA "info frames") */
-- 
2.28.0