From 70a410e06d6fd169e55f366422d570bba47be390 Mon Sep 17 00:00:00 2001
From: Gary Li <garyli12@amd.com>
Date: Thu, 14 Apr 2022 09:01:48 -0400
Subject: drm/amd/display: Maintain current link settings in link loss
 interrupt
Git-commit: 9fbfeaf110714dd6176e209230569c2dd9a9ad08
Patch-mainline: v5.19-rc1
References: jsc#PED-1166 jsc#PED-1168 jsc#PED-1170 jsc#PED-1218 jsc#PED-1220 jsc#PED-1222 jsc#PED-1223 jsc#PED-1225

[Why]
DP compliance test case 400.3.2.3 is failed because in link loss interrupt
the current link settings is not used in the DP link training.

[How]
In link loss interrupt, use the current link settings in the following DP
link training.

Reviewed-by: Wenjing Liu <Wenjing.Liu@amd.com>
Acked-by: Tom Chung <chiahsuan.chung@amd.com>
Signed-off-by: Gary Li <garyli12@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Acked-by: Patrik Jakobsson <pjakobsson@suse.de>
---
 drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c b/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c
index a1b7d5902ded..5addac0acfdb 100644
--- a/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c
+++ b/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c
@@ -4576,6 +4576,7 @@ void dc_link_dp_handle_link_loss(struct dc_link *link)
 {
 	int i;
 	struct pipe_ctx *pipe_ctx;
+	struct dc_link_settings prev_link_settings = link->preferred_link_setting;
 
 	for (i = 0; i < MAX_PIPES; i++) {
 		pipe_ctx = &link->dc->current_state->res_ctx.pipe_ctx[i];
@@ -4586,6 +4587,10 @@ void dc_link_dp_handle_link_loss(struct dc_link *link)
 	if (pipe_ctx == NULL || pipe_ctx->stream == NULL)
 		return;
 
+	/* toggle stream state with the preference for current link settings */
+	dc_link_set_preferred_training_settings((struct dc *)link->dc,
+					&link->cur_link_settings, NULL, link, true);
+
 	for (i = 0; i < MAX_PIPES; i++) {
 		pipe_ctx = &link->dc->current_state->res_ctx.pipe_ctx[i];
 		if (pipe_ctx && pipe_ctx->stream && !pipe_ctx->stream->dpms_off &&
@@ -4601,6 +4606,10 @@ void dc_link_dp_handle_link_loss(struct dc_link *link)
 			core_link_enable_stream(link->dc->current_state, pipe_ctx);
 		}
 	}
+
+	/* restore previous link settings preference */
+	dc_link_set_preferred_training_settings((struct dc *)link->dc,
+					&prev_link_settings, NULL, link, true);
 }
 
 bool dc_link_handle_hpd_rx_irq(struct dc_link *link, union hpd_irq_data *out_hpd_irq_dpcd_data, bool *out_link_loss,
-- 
2.38.1