From 73144a6bdf9dc186b0ab15944c75a805dc5bb3e7 Mon Sep 17 00:00:00 2001
From: Wenjing Liu <wenjing.liu@amd.com>
Date: Fri, 24 Sep 2021 16:12:34 -0400
Subject: drm/amd/display: add DP2.0 debug option to set MST_EN for SST stream
Git-commit: 05692bb02abd63959fde2108dbe80dd5082e4f89
Patch-mainline: v5.16-rc1
References: jsc#PED-1166 jsc#PED-1168 jsc#PED-1170 jsc#PED-1218 jsc#PED-1220 jsc#PED-1222 jsc#PED-1223 jsc#PED-1225
[why]
Some DP2.0 RX requires us to set MST_EN even for SST configuration.
We added this debug option so we can configure this temporary workaround
for the RX.
Reviewed-by: George Shen <george.shen@amd.com>
Acked-by: Agustin Gutierrez Sanchez <agustin.gutierrez@amd.com>
Signed-off-by: Wenjing Liu <wenjing.liu@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Acked-by: Patrik Jakobsson <pjakobsson@suse.de>
---
drivers/gpu/drm/amd/display/dc/core/dc_link.c | 7 ++++++-
drivers/gpu/drm/amd/display/dc/dc.h | 1 +
2 files changed, 7 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 ca5dc3c168ec..fa11a2b094ba 100644
--- a/drivers/gpu/drm/amd/display/dc/core/dc_link.c
+++ b/drivers/gpu/drm/amd/display/dc/core/dc_link.c
@@ -1869,8 +1869,13 @@ static enum dc_status enable_link_dp(struct dc_state *state,
do_fallback = true;
#if defined(CONFIG_DRM_AMD_DC_DCN)
+ /*
+ * Temporary w/a to get DP2.0 link rates to work with SST.
+ * TODO DP2.0 - Workaround: Remove w/a if and when the issue is resolved.
+ */
if (dp_get_link_encoding_format(&link_settings) == DP_128b_132b_ENCODING &&
- pipe_ctx->stream->signal == SIGNAL_TYPE_DISPLAY_PORT) {
+ pipe_ctx->stream->signal == SIGNAL_TYPE_DISPLAY_PORT &&
+ link->dc->debug.set_mst_en_for_sst) {
dp_enable_mst_on_sink(link, true);
}
#endif
diff --git a/drivers/gpu/drm/amd/display/dc/dc.h b/drivers/gpu/drm/amd/display/dc/dc.h
index dd995905b0cb..254b760ae91f 100644
--- a/drivers/gpu/drm/amd/display/dc/dc.h
+++ b/drivers/gpu/drm/amd/display/dc/dc.h
@@ -664,6 +664,7 @@ struct dc_debug_options {
#if defined(CONFIG_DRM_AMD_DC_DCN)
/* TODO - remove once tested */
bool legacy_dp2_lt;
+ bool set_mst_en_for_sst;
#endif
union mem_low_power_enable_options enable_mem_low_power;
union root_clock_optimization_options root_clock_optimization;
--
2.38.1