From: Wayne Lin <wayne.lin@xxxxxxx> [Why] When unplug one of monitors connected after mst hub, encounter null pointer dereference. It's due to dc_sink get released immediately in early_unregister() or detect_ctx(). When commit new state which directly referring to info stored in dc_sink will cause null pointer dereference. [how] Remove redundant checking condition. Relevant condition should already be covered by checking if dsc_aux is null or not. Also reset dsc_aux to NULL when the connector is disconnected. Reviewed-by: Jerry Zuo <jerry.zuo@xxxxxxx> Acked-by: Zaeem Mohamed <zaeem.mohamed@xxxxxxx> Signed-off-by: Wayne Lin <wayne.lin@xxxxxxx> --- .../drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c | 12 ++++-------- 1 file changed, 4 insertions(+), 8 deletions(-) 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 ac60f688660a..f60d55c17fb4 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 @@ -182,6 +182,8 @@ amdgpu_dm_mst_connector_early_unregister(struct drm_connector *connector) dc_sink_release(dc_sink); aconnector->dc_sink = NULL; aconnector->edid = NULL; + aconnector->dsc_aux = NULL; + port->passthrough_aux = NULL; } aconnector->mst_status = MST_STATUS_DEFAULT; @@ -498,6 +500,8 @@ dm_dp_mst_detect(struct drm_connector *connector, dc_sink_release(aconnector->dc_sink); aconnector->dc_sink = NULL; aconnector->edid = NULL; + aconnector->dsc_aux = NULL; + port->passthrough_aux = NULL; amdgpu_dm_set_mst_status(&aconnector->mst_status, MST_REMOTE_EDID | MST_ALLOCATE_NEW_PAYLOAD | MST_CLEAR_ALLOCATED_PAYLOAD, @@ -1238,14 +1242,6 @@ static bool is_dsc_need_re_compute( if (!aconnector || !aconnector->dsc_aux) continue; - /* - * check if cached virtual MST DSC caps are available and DSC is supported - * as per specifications in their Virtual DPCD registers. - */ - if (!(aconnector->dc_sink->dsc_caps.dsc_dec_caps.is_dsc_supported || - aconnector->dc_link->dpcd_caps.dsc_caps.dsc_basic_caps.fields.dsc_support.DSC_PASSTHROUGH_SUPPORT)) - continue; - stream_on_link[new_stream_on_link_num] = aconnector; new_stream_on_link_num++; -- 2.34.1
