From da2f84ba73df11186cf23bec45d039f3b9162bd8 Mon Sep 17 00:00:00 2001
From: Harry Wentland <harry.wentland@amd.com>
Date: Tue, 21 Jan 2020 16:29:54 -0500
Subject: Revert "drm/amd/display: Don't skip link training for empty dongle"
Git-commit: da2f84ba73df11186cf23bec45d039f3b9162bd8
Patch-mainline: v5.6-rc1
References: bsc#1152489

This reverts commit 80adaebd2d411b7d6872a097634848a71eb13d20.

[WHY]
This change was working around a regression that occured in this:
commit 0301ccbaf67d ("drm/amd/display: DP Compliance 400.1.1 failure")

With the fix to run verify_link_cap when the SINK_COUNT of
dongles becomes non-zero this change is no longer needed.

Cc: Louis Li <Ching-shih.Li@amd.com>
Cc: Wenjing Liu <Wenjing.Liu@amd.com>
Cc: Hersen Wu <hersenxs.wu@amd.com>
Cc: Eric Yang <Eric.Yang2@amd.com>
Reviewed-by: Wenjing Liu <Wenjing.Liu@amd.com>
Signed-off-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
---
 drivers/gpu/drm/amd/display/dc/core/dc_link.c |   17 ++---------------
 1 file changed, 2 insertions(+), 15 deletions(-)

--- a/drivers/gpu/drm/amd/display/dc/core/dc_link.c
+++ b/drivers/gpu/drm/amd/display/dc/core/dc_link.c
@@ -787,25 +787,12 @@ bool dc_link_detect(struct dc_link *link
 				if (memcmp(&link->dpcd_caps, &prev_dpcd_caps, sizeof(struct dpcd_caps)))
 					same_dpcd = false;
 			}
-			/* Active dongle plug in without display or downstream unplug*/
+			/* Active dongle downstream unplug*/
 			if (link->type == dc_connection_active_dongle &&
 				link->dpcd_caps.sink_count.bits.SINK_COUNT == 0) {
-				if (prev_sink != NULL) {
+				if (prev_sink != NULL)
 					/* Downstream unplug */
 					dc_sink_release(prev_sink);
-				} else {
-					/* Empty dongle plug in */
-					for (i = 0; i < LINK_TRAINING_MAX_VERIFY_RETRY; i++) {
-						int fail_count = 0;
-
-						dp_verify_link_cap(link,
-								  &link->reported_link_cap,
-								  &fail_count);
-
-						if (fail_count == 0)
-							break;
-					}
-				}
 				return true;
 			}