Commit f638d750 authored by Nicholas Kazlauskas's avatar Nicholas Kazlauskas Committed by Alex Deucher
Browse files

drm/amd/display: Fix deadlock when falling back to v2 from v3 



[Why]
A deadlock in the kernel occurs when we fallback from the V3 to V2
add_topology_to_display or remove_topology_to_display because they
both try to acquire the dtm_mutex but recursive locking isn't
supported on mutex_lock().

[How]
Make the mutex_lock/unlock more fine grained and move them up such that
they're only required for the psp invocation itself.

Fixes: bf62221e ("drm/amd/display: Add DCN3.1 HDCP support")

Signed-off-by: default avatarNicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Reviewed-by: default avatarAric Cyr <aric.cyr@amd.com>
Signed-off-by: default avatarAlex Deucher <alexander.deucher@amd.com>
parent 1e5588d1

drivers/gpu/drm/amd/display/modules/hdcp/hdcp_psp.c

+2 −4
Original line number Diff line number Diff line
@@ -105,6 +105,7 @@ static enum mod_hdcp_status remove_display_from_topology_v3( 
	dtm_cmd->dtm_status = TA_DTM_STATUS__GENERIC_FAILURE;



	psp_dtm_invoke(psp, dtm_cmd->cmd_id);

	mutex_unlock(&psp->dtm_context.mutex);



	if (dtm_cmd->dtm_status != TA_DTM_STATUS__SUCCESS) {

		status = remove_display_from_topology_v2(hdcp, index);
@@ -115,8 +116,6 @@ static enum mod_hdcp_status remove_display_from_topology_v3( 
		HDCP_TOP_REMOVE_DISPLAY_TRACE(hdcp, display->index);

	}



	mutex_unlock(&psp->dtm_context.mutex);



	return status;

}
@@ -205,6 +204,7 @@ static enum mod_hdcp_status add_display_to_topology_v3( 
	dtm_cmd->dtm_in_message.topology_update_v3.link_hdcp_cap = link->hdcp_supported_informational;



	psp_dtm_invoke(psp, dtm_cmd->cmd_id);

	mutex_unlock(&psp->dtm_context.mutex);



	if (dtm_cmd->dtm_status != TA_DTM_STATUS__SUCCESS) {

		status = add_display_to_topology_v2(hdcp, display);
@@ -214,8 +214,6 @@ static enum mod_hdcp_status add_display_to_topology_v3( 
		HDCP_TOP_ADD_DISPLAY_TRACE(hdcp, display->index);

	}



	mutex_unlock(&psp->dtm_context.mutex);



	return status;

}