From 8ecdf471087fe5785d38f850ed7a8d67f5c32d64 Mon Sep 17 00:00:00 2001
From: Zhan Liu <Zhan.Liu@amd.com>
Date: Thu, 27 Jan 2022 22:08:53 -0500
Subject: drm/amd/display: keep eDP Vdd on when eDP stream is already enabled
Git-commit: ad787771b43602d64e02b5963f4192232b46366b
Patch-mainline: v5.17-rc4
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]
Even if can_apply_edp_fast_boot is set to 1 at boot, this flag will
be cleared to 0 at S3 resume.

[How]
Keep eDP Vdd on when eDP stream is already enabled.

Reviewed-by: Charlene Liu <Charlene.Liu@amd.com>
Acked-by: Jasdeep Dhillon <jdhillon@amd.com>
Signed-off-by: Zhan Liu <Zhan.Liu@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>
---
 .../display/dc/dce110/dce110_hw_sequencer.c   | 24 +++++++++++++++++--
 1 file changed, 22 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/amd/display/dc/dce110/dce110_hw_sequencer.c b/drivers/gpu/drm/amd/display/dc/dce110/dce110_hw_sequencer.c
index 26ec69bb5db9..eb2755bdb30e 100644
--- a/drivers/gpu/drm/amd/display/dc/dce110/dce110_hw_sequencer.c
+++ b/drivers/gpu/drm/amd/display/dc/dce110/dce110_hw_sequencer.c
@@ -1834,9 +1834,29 @@ void dce110_enable_accelerated_mode(struct dc *dc, struct dc_state *context)
 				break;
 			}
 		}
-		// We are trying to enable eDP, don't power down VDD
-		if (can_apply_edp_fast_boot)
+
+		/*
+		 * TO-DO: So far the code logic below only addresses single eDP case.
+		 * For dual eDP case, there are a few things that need to be
+		 * implemented first:
+		 *
+		 * 1. Change the fastboot logic above, so eDP link[0 or 1]'s
+		 * stream[0 or 1] will all be checked.
+		 *
+		 * 2. Change keep_edp_vdd_on to an array, and maintain keep_edp_vdd_on
+		 * for each eDP.
+		 *
+		 * Once above 2 things are completed, we can then change the logic below
+		 * correspondingly, so dual eDP case will be fully covered.
+		 */
+
+		// We are trying to enable eDP, don't power down VDD if eDP stream is existing
+		if ((edp_stream_num == 1 && edp_streams[0] != NULL) || can_apply_edp_fast_boot) {
 			keep_edp_vdd_on = true;
+			DC_LOG_EVENT_LINK_TRAINING("Keep eDP Vdd on\n");
+		} else {
+			DC_LOG_EVENT_LINK_TRAINING("No eDP stream enabled, turn eDP Vdd off\n");
+		}
 	}
 
 	// Check seamless boot support
-- 
2.38.1