drm/amd/display: skip CLEAR_PAYLOAD_ID_TABLE if device mst_en is 0

From Peichen Huang
56562676102e135e7aebada26c2aea146a5b5ad0 in linux-6.1.y/6.1.45
a1c9a1e27022d13c70a14c4faeab6ce293ad043b in mainline linux

diff --git a/sys/dev/pci/drm/amd/display/dc/core/dc_link.c b/sys/dev/pci/drm/amd/display/dc/core/dc_link.c
index 13598a2..bba7e06 100644 (file)
--- a/sys/dev/pci/drm/amd/display/dc/core/dc_link.c
+++ b/sys/dev/pci/drm/amd/display/dc/core/dc_link.c
@@ -2092,6 +2092,7 @@ static enum dc_status enable_link_dp_mst(
                struct pipe_ctx *pipe_ctx)
 {
        struct dc_link *link = pipe_ctx->stream->link;
+       unsigned char mstm_cntl;
 
        /* sink signal type after MST branch is MST. Multiple MST sinks
         * share one link. Link DP PHY is enable or training only once.
@@ -2100,7 +2101,9 @@ static enum dc_status enable_link_dp_mst(
                return DC_OK;
 
        /* clear payload table */
-       dm_helpers_dp_mst_clear_payload_allocation_table(link->ctx, link);
+       core_link_read_dpcd(link, DP_MSTM_CTRL, &mstm_cntl, 1);
+       if (mstm_cntl & DP_MST_EN)
+               dm_helpers_dp_mst_clear_payload_allocation_table(link->ctx, link);
 
        /* to make sure the pending down rep can be processed
         * before enabling the link