This is a note to let you know that I've just added the patch titled
drm/amd/display: clear optc underflow before turn off odm clock
to the 5.4-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-clear-optc-underflow-before-turn-off.patch
and it can be found in the queue-5.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 9c601b73f56f994330b4ec91edf4fa955adfd5c2
Author: Fudong Wang <Fudong.Wang@xxxxxxx>
Date: Wed Jul 27 12:01:29 2022 +0800
drm/amd/display: clear optc underflow before turn off odm clock
[ Upstream commit b2a93490201300a749ad261b5c5d05cb50179c44 ]
[Why]
After ODM clock off, optc underflow bit will be kept there always and clear not work.
We need to clear that before clock off.
[How]
Clear that if have when clock off.
Reviewed-by: Alvin Lee <alvin.lee2@xxxxxxx>
Acked-by: Tom Chung <chiahsuan.chung@xxxxxxx>
Signed-off-by: Fudong Wang <Fudong.Wang@xxxxxxx>
Tested-by: Daniel Wheeler <daniel.wheeler@xxxxxxx>
Signed-off-by: Alex Deucher <alexander.deucher@xxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_optc.c b/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_optc.c
index e74a07d03fde9..4b0200e96eb77 100644
--- a/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_optc.c
+++ b/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_optc.c
@@ -425,6 +425,11 @@ void optc1_enable_optc_clock(struct timing_generator *optc, bool enable)
OTG_CLOCK_ON, 1,
1, 1000);
} else {
+
+ //last chance to clear underflow, otherwise, it will always there due to clock is off.
+ if (optc->funcs->is_optc_underflow_occurred(optc) == true)
+ optc->funcs->clear_optc_underflow(optc);
+
REG_UPDATE_2(OTG_CLOCK_CONTROL,
OTG_CLOCK_GATE_DIS, 0,
OTG_CLOCK_EN, 0);
