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 411f89218e0194fcd80980b239c9e514acc0d9f8..cb5c44b339e0946932494e52eec687dc900e8392 100644 (file)
--- 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);