From d7c7df629483a14bb696bdcb15bc76d3cfc2c344 Mon Sep 17 00:00:00 2001
From: Zhan Liu <zhan.liu@amd.com>
Date: Mon, 23 Dec 2019 15:37:24 -0500
Subject: drm/amd/display: Don't disable DP PHY when link loss happens
Git-commit: 2d5ef0b42c0bca33aaaff2f1b98855e4e3225a0f
Patch-mainline: v5.6-rc1
References: jsc#SLE-12680, jsc#SLE-12880, jsc#SLE-12882, jsc#SLE-12883, jsc#SLE-13496, jsc#SLE-15322

[Why]
There is a use case that link loss happens accidentally,
and we need to recover that link loss as soon as possible.
Under this circumstance, we will perform link training,
and try to recover the link that's just lost.

However, if link PHY is disabled before link training
happens, then DP display will never come back again.

Also, please note that dropping this disable_phy function
call won't break USB-C hotplug functionality.
(This line of code was firstly introduced associated with
a patch to fix USB-C hotplug issue)

[How]
Don't disable DP transmitter and its encoder before link
training happens, even if link loss is detected.

Signed-off-by: Zhan Liu <zhan.liu@amd.com>
Reviewed-by: Harry Wentland <harry.wentland@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_dp.c | 1 -
 1 file changed, 1 deletion(-)

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 38b0f4347383..49f48d432923 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
@@ -2876,7 +2876,6 @@ bool dc_link_handle_hpd_rx_irq(struct dc_link *link, union hpd_irq_data *out_hpd
 			return false;
 
 		previous_link_settings = link->cur_link_settings;
-		dp_disable_link_phy(link, pipe_ctx->stream->signal);
 
 		perform_link_training_with_retries(&previous_link_settings,
 			true, LINK_TRAINING_ATTEMPTS,
-- 
2.28.0