[PATCH 6.6 352/396] drm/amd/display: Fix hang/underflow when transitioning to ODM4:1

Greg Kroah-Hartman
2024-04-01T16:53:53Z

From: Ilya Bakoulin <ilya.bakoulin@amd.com>

[ Upstream commit e7b2b108cdeab76a7e7324459e50b0c1214c0386 ]

[Why]
Under some circumstances, disabling an OPTC and attempting to reclaim
its OPP(s) for a different OPTC could cause a hang/underflow due to OPPs
not being properly disconnected from the disabled OPTC.

[How]
Ensure that all OPPs are unassigned from an OPTC when it gets disabled.

Reviewed-by: Alvin Lee <alvin.lee2@amd.com>
Acked-by: Wayne Lin <wayne.lin@amd.com>
Signed-off-by: Ilya Bakoulin <ilya.bakoulin@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Stable-dep-of: b4e05bb1dec5 ("drm/amd/display: Clear OPTC mem select on disable")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/gpu/drm/amd/display/dc/dcn32/dcn32_optc.c | 7 +++++++
1 file changed, 7 insertions(+)

diff --git a/drivers/gpu/drm/amd/display/dc/dcn32/dcn32_optc.c b/drivers/gpu/drm/amd/display/dc/dcn32/dcn32_optc.c
index 8abb94f60078f..b1fcc91b65a32 100644
--- a/drivers/gpu/drm/amd/display/dc/dcn32/dcn32_optc.c
+++ b/drivers/gpu/drm/amd/display/dc/dcn32/dcn32_optc.c
@@ -148,6 +148,13 @@ static bool optc32_disable_crtc(struct timing_generator *optc)
REG_UPDATE(OTG_CONTROL,
OTG_MASTER_EN, 0);

+ REG_UPDATE_5(OPTC_DATA_SOURCE_SELECT,
+ OPTC_SEG0_SRC_SEL, 0xf,
+ OPTC_SEG1_SRC_SEL, 0xf,
+ OPTC_SEG2_SRC_SEL, 0xf,
+ OPTC_SEG3_SRC_SEL, 0xf,
+ OPTC_NUM_OF_INPUT_SEGMENT, 0);
+
REG_UPDATE(CONTROL,
VTG0_ENABLE, 0);

--
2.43.0