From ad76744b041d8c87ef1c9adbb04fb7eaa20a179e Mon Sep 17 00:00:00 2001 From: Nicholas Kazlauskas Date: Fri, 22 Oct 2021 16:14:24 -0400 Subject: [PATCH] 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: bf62221e9d0e ("drm/amd/display: Add DCN3.1 HDCP support") Signed-off-by: Nicholas Kazlauskas Reviewed-by: Aric Cyr Signed-off-by: Alex Deucher Cc: stable@vger.kernel.org --- drivers/gpu/drm/amd/display/modules/hdcp/hdcp_psp.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) diff --git a/drivers/gpu/drm/amd/display/modules/hdcp/hdcp_psp.c b/drivers/gpu/drm/amd/display/modules/hdcp/hdcp_psp.c index e9bd84ec027d..be61975f1470 100644 --- a/drivers/gpu/drm/amd/display/modules/hdcp/hdcp_psp.c +++ b/drivers/gpu/drm/amd/display/modules/hdcp/hdcp_psp.c @@ -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; }