This is a note to let you know that I've just added the patch titled
drm/amd/display: ensure dentist display clock update finished in DCN20
to the 5.13-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-ensure-dentist-display-clock-update-finished-in-dcn20.patch
and it can be found in the queue-5.13 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From b53e041d8e4308f7324999398aec092dbcb130f5 Mon Sep 17 00:00:00 2001
From: Dale Zhao <dale.zhao@xxxxxxx>
Date: Fri, 16 Jul 2021 09:38:17 +0800
Subject: drm/amd/display: ensure dentist display clock update finished in DCN20
From: Dale Zhao <dale.zhao@xxxxxxx>
commit b53e041d8e4308f7324999398aec092dbcb130f5 upstream.
[Why]
We don't check DENTIST_DISPCLK_CHG_DONE to ensure dentist
display clockis updated to target value. In some scenarios with large
display clock margin, it will deliver unfinished display clock and cause
issues like display black screen.
[How]
Checking DENTIST_DISPCLK_CHG_DONE to ensure display clock
has been update to target value before driver do other clock related
actions.
Reviewed-by: Cyr Aric <aric.cyr@xxxxxxx>
Acked-by: Solomon Chiu <solomon.chiu@xxxxxxx>
Signed-off-by: Dale Zhao <dale.zhao@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/clk_mgr/dcn20/dcn20_clk_mgr.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/drivers/gpu/drm/amd/display/dc/clk_mgr/dcn20/dcn20_clk_mgr.c
+++ b/drivers/gpu/drm/amd/display/dc/clk_mgr/dcn20/dcn20_clk_mgr.c
@@ -135,7 +135,7 @@ void dcn20_update_clocks_update_dentist(
REG_UPDATE(DENTIST_DISPCLK_CNTL,
DENTIST_DISPCLK_WDIVIDER, dispclk_wdivider);
-// REG_WAIT(DENTIST_DISPCLK_CNTL, DENTIST_DISPCLK_CHG_DONE, 1, 5, 100);
+ REG_WAIT(DENTIST_DISPCLK_CNTL, DENTIST_DISPCLK_CHG_DONE, 1, 50, 1000);
REG_UPDATE(DENTIST_DISPCLK_CNTL,
DENTIST_DPPCLK_WDIVIDER, dppclk_wdivider);
REG_WAIT(DENTIST_DISPCLK_CNTL, DENTIST_DPPCLK_CHG_DONE, 1, 5, 100);
Patches currently in stable-queue which might be from dale.zhao@xxxxxxx are
queue-5.13/drm-amd-display-ensure-dentist-display-clock-update-finished-in-dcn20.patch
