Commit fcf6a49d authored by Wayne Lin's avatar Wayne Lin Committed by Alex Deucher
Browse files

drm/amd/display: Don't refer to dc_sink in is_dsc_need_re_compute 



[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: default avatarJerry Zuo <jerry.zuo@amd.com>
Acked-by: default avatarZaeem Mohamed <zaeem.mohamed@amd.com>
Signed-off-by: default avatarWayne Lin <wayne.lin@amd.com>
Tested-by: default avatarDaniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: default avatarAlex Deucher <alexander.deucher@amd.com>
parent fc6d61ad

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c

+4 −8
Original line number Diff line number Diff line
@@ -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++;