drm/amd/display: Add fallback and abort paths for DP link training.

[Why]
When enabling a DisplayPort stream:
- Optionally reducing link bandwidth between failed link training
attempts should progressively relax training requirements.
- Abandoning link training altogether if a sink is unplugged should
avoid unnecessary training attempts.

[How]
- Add fallback parameter to DP link training function and reduce link
bandwidth between failed training attempts as long as stream bandwidth
requirements are met.
- Add training status for sink unplug and abort training when this
status is reported.

Signed-off-by: Jimmy Kizito <Jimmy.Kizito@amd.com>
Reviewed-by: Jun Lei <Jun.Lei@amd.com>
Acked-by: Stylon Wang <stylon.wang@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

1 files changed, 2 insertions, 1 deletions

diff --git a/drivers/gpu/drm/amd/display/dc/core/dc_link_hwss.c b/drivers/gpu/drm/amd/display/dc/core/dc_link_hwss.c
index b426f878fb99..13c5c4a34a58 100644
--- a/drivers/gpu/drm/amd/display/dc/core/dc_link_hwss.c
+++ b/drivers/gpu/drm/amd/display/dc/core/dc_link_hwss.c
@@ -384,7 +384,8 @@ void dp_retrain_link_dp_test(struct dc_link *link,
 					skip_video_pattern,
 					LINK_TRAINING_ATTEMPTS,
 					&pipes[i],
-					SIGNAL_TYPE_DISPLAY_PORT);
+					SIGNAL_TYPE_DISPLAY_PORT,
+					false);
 
 			link->dc->hwss.enable_stream(&pipes[i]);