This is a note to let you know that I've just added the patch titled drm/amd/display: increase Z9 latency to workaround underflow in Z9 to the 5.14-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: drm-amd-display-increase-z9-latency-to-workaround-underflow-in-z9.patch and it can be found in the queue-5.14 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 4835ea6c173a8d8dfbfdbb21c4cd987d12681610 Mon Sep 17 00:00:00 2001 From: Eric Yang <Eric.Yang2@xxxxxxx> Date: Thu, 30 Sep 2021 13:46:45 -0400 Subject: drm/amd/display: increase Z9 latency to workaround underflow in Z9 From: Eric Yang <Eric.Yang2@xxxxxxx> 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@xxxxxxx> Acked-by: Agustin Gutierrez Sanchez <agustin.gutierrez@xxxxxxx> Signed-off-by: Eric Yang <Eric.Yang2@xxxxxxx> Tested-by: Daniel Wheeler <daniel.wheeler@xxxxxxx> Signed-off-by: Alex Deucher <alexander.deucher@xxxxxxx> Cc: stable@xxxxxxxxxxxxxxx Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/gpu/drm/amd/display/dc/dcn31/dcn31_resource.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- 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 .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, Patches currently in stable-queue which might be from Eric.Yang2@xxxxxxx are queue-5.14/drm-amd-display-increase-z9-latency-to-workaround-underflow-in-z9.patch