From c9e0ab86b2e03154bb898cd2f851827783224727 Mon Sep 17 00:00:00 2001 From: Lyude Paul Date: Mon, 19 Nov 2018 15:00:10 +0000 Subject: [PATCH] drm/amd/dm: Don't forget to attach MST encoders MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit The change fixed huge delay in SST daisy chain and S3 soft hang observed in 4.19 kernel rebase. Regression point in drm: drm/fb-helper: Eliminate the .best_encoder() usage The aux sequence is altered due to the failure in drm_connector_for_each_possible_encoder(). The failure is caused by missing attached encoder in the process of adding MST connector.   drm_dp_send_enum_path_resources() aux transaction is pushed after mode probe, which causes conflict to drm_dp_mst_i2c_xfer(), leading to the transaction timeout. Signed-off-by: Lyude Paul Reviewed-by: Jerry (Fangzhi) Zuo Cc: Stable Signed-off-by: Alex Deucher --- drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c index d02c32a1039c..0cca1809fdcd 100644 --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c @@ -342,6 +342,8 @@ dm_dp_add_mst_connector(struct drm_dp_mst_topology_mgr *mgr, master->connector_id); aconnector->mst_encoder = dm_dp_create_fake_mst_encoder(master); + drm_connector_attach_encoder(&aconnector->base, + &aconnector->mst_encoder->base); /* * TODO: understand why this one is needed -- 2.30.2