[PATCH 4.19 51/56] drm/amd/display: clear optc underflow before turn off odm clock

Greg Kroah-Hartman
2022-09-02T12:35:08Z

From: Fudong Wang <Fudong.Wang@amd.com>

[ 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>
---
drivers/gpu/drm/amd/display/dc/dcn10/dcn10_optc.c | 5 +++++
1 file changed, 5 insertions(+)

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 411f89218e019..cb5c44b339e09 100644
--- a/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_optc.c
+++ b/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_optc.c
@@ -452,6 +452,11 @@ 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);
--
2.35.1