From 85cf47160d0eb6eca784dc4848efcf30b18d5a2f Mon Sep 17 00:00:00 2001
From: Eric Yang <Eric.Yang2@amd.com>
Date: Thu, 30 Sep 2021 13:46:45 -0400
Subject: [PATCH] drm/amd/display: increase Z9 latency to workaround underflow in Z9
Git-commit: 4835ea6c173a8d8dfbfdbb21c4cd987d12681610
Patch-mainline: v5.15
References: stable-5.14.16

commit 4835ea6c173a8d8dfbfdbb21c4cd987d12681610 upstream.

[Why]
Z9 latency is higher than when we originally tuned the watermark
parameters, causing underflow. Increasing the value until the latency
issues is resolved.

Reviewed-by: Nicholas Kazlauskas <Nicholas.Kazlauskas@amd.com>
Acked-by: Agustin Gutierrez Sanchez <agustin.gutierrez@amd.com>
Signed-off-by: Eric Yang <Eric.Yang2@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/gpu/drm/amd/display/dc/dcn31/dcn31_resource.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/amd/display/dc/dcn31/dcn31_resource.c b/drivers/gpu/drm/amd/display/dc/dcn31/dcn31_resource.c
index fc643ee0e543..4c9eed3f0713 100644
--- a/drivers/gpu/drm/amd/display/dc/dcn31/dcn31_resource.c
+++ b/drivers/gpu/drm/amd/display/dc/dcn31/dcn31_resource.c
@@ -217,8 +217,8 @@ struct _vcs_dpi_soc_bounding_box_st dcn3_1_soc = {
 	.num_states = 5,
 	.sr_exit_time_us = 9.0,
 	.sr_enter_plus_exit_time_us = 11.0,
-	.sr_exit_z8_time_us = 402.0,
-	.sr_enter_plus_exit_z8_time_us = 520.0,
+	.sr_exit_z8_time_us = 442.0,
+	.sr_enter_plus_exit_z8_time_us = 560.0,
 	.writeback_latency_us = 12.0,
 	.dram_channel_width_bytes = 4,
 	.round_trip_ping_latency_dcfclk_cycles = 106,
-- 
2.26.2