From: Fudong Wang <Fudong.Wang@amd.com>
Date: Wed, 27 Jul 2022 04:01:29 +0000 (+0800)
Subject: drm/amd/display: clear optc underflow before turn off odm clock
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=5ee30bcfdb32526233d2572f3d9ec371928679f1;p=linux.git

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@amd.com>
Acked-by: Tom Chung <chiahsuan.chung@amd.com>
Signed-off-by: Fudong Wang <Fudong.Wang@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---

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 37848f4577b18..92fee47278e5a 100644
--- a/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_optc.c
+++ b/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_optc.c
@@ -480,6 +480,11 @@ 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);