Wayne Lin 404d85a71d drm/amd/display: Don't write DP_MSTM_CTRL after LT
commit bc068194f548ef1f230d96c4398046bf59165992 upstream.

[Why]
Observe after suspend/resme, we can't light up mst monitors under specific
mst hub. The reason is that driver still writes DPCD DP_MSTM_CTRL after LT.
It's forbidden even we write the same value for that dpcd register.

[How]
We already resume the mst branch device dpcd settings during
resume_mst_branch_status(). Leverage drm_dp_mst_topology_queue_probe() to
only probe the topology, not calling drm_dp_mst_topology_mgr_resume() which
will set DP_MSTM_CTRL as well.

Reviewed-by: Jerry Zuo <jerry.zuo@amd.com>
Signed-off-by: Wayne Lin <Wayne.Lin@amd.com>
Signed-off-by: Zaeem Mohamed <zaeem.mohamed@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
[cascardo: adjust context in local declarations]
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@igalia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-04-07 10:06:36 +02:00
2025-04-07 10:06:35 +02:00
2022-09-28 09:02:20 +02:00
2025-03-28 21:59:57 +01:00

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