From 56562676102e135e7aebada26c2aea146a5b5ad0 Mon Sep 17 00:00:00 2001 From: Peichen Huang Date: Mon, 20 Mar 2023 09:34:23 +0800 Subject: [PATCH] drm/amd/display: skip CLEAR_PAYLOAD_ID_TABLE if device mst_en is 0 commit a1c9a1e27022d13c70a14c4faeab6ce293ad043b upstream. [Why] Some dock and mst monitor don't like to receive CLEAR_PAYLOAD_ID_TABLE when mst_en is set to 0. It doesn't make sense to do so in source side, either. [How] Don't send CLEAR_PAYLOAD_ID_TABLE if mst_en is 0 Reviewed-by: George Shen Acked-by: Qingqing Zhuo Signed-off-by: Peichen Huang Tested-by: Daniel Wheeler Signed-off-by: Alex Deucher [ 6.1.y doesn't have the file rename from 54618888d1ea7 ("drm/amd/display: break down dc_link.c") ] Signed-off-by: Mario Limonciello Signed-off-by: Greg Kroah-Hartman --- drivers/gpu/drm/amd/display/dc/core/dc_link.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/amd/display/dc/core/dc_link.c b/drivers/gpu/drm/amd/display/dc/core/dc_link.c index 5d53e54ebe90..c2c6c4587a5c 100644 --- a/drivers/gpu/drm/amd/display/dc/core/dc_link.c +++ b/drivers/gpu/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