[PATCH 6/8] drm/amd/display: Add w/a to disable DP dual mode on certain ports

[Alan Liu]

From: George Shen <george.shen at amd.com>

[Why]
Certain ports on DCN3.2 configs do not properly populate the BIOS
info table flag to indicate DP dual mode is unsupported.

[How]
Add a workaround to disable DP dual mode on the ports with the missing
BIOS info table flag.

Reviewed-by: Michael Strauss <Michael.Strauss at amd.com>
Acked-by: Alan Liu <HaoPing.Liu at amd.com>
Signed-off-by: George Shen <george.shen at amd.com>
---
 drivers/gpu/drm/amd/display/dc/dc.h                   | 1 +
 drivers/gpu/drm/amd/display/dc/dcn32/dcn32_resource.c | 1 +
 drivers/gpu/drm/amd/display/dc/link/link_detection.c  | 4 ++++
 3 files changed, 6 insertions(+)

diff --git a/drivers/gpu/drm/amd/display/dc/dc.h b/drivers/gpu/drm/amd/display/dc/dc.h
index fea68383bb61..fe60816653d0 100644
--- a/drivers/gpu/drm/amd/display/dc/dc.h
+++ b/drivers/gpu/drm/amd/display/dc/dc.h
@@ -887,6 +887,7 @@ struct dc_debug_options {
 	bool override_odm_optimization;
 	bool minimize_dispclk_using_odm;
 	bool disable_subvp_high_refresh;
+	bool disable_dp_plus_plus_wa;
 };
 
 struct gpu_info_soc_bounding_box_v1_0;
diff --git a/drivers/gpu/drm/amd/display/dc/dcn32/dcn32_resource.c b/drivers/gpu/drm/amd/display/dc/dcn32/dcn32_resource.c
index a49323885874..4de2f8813dce 100644
--- a/drivers/gpu/drm/amd/display/dc/dcn32/dcn32_resource.c
+++ b/drivers/gpu/drm/amd/display/dc/dcn32/dcn32_resource.c
@@ -729,6 +729,7 @@ static const struct dc_debug_options debug_defaults_drv = {
 	.disable_fpo_vactive = false,
 	.disable_boot_optimizations = false,
 	.disable_subvp_high_refresh = true,
+	.disable_dp_plus_plus_wa = true,
 };
 
 static const struct dc_debug_options debug_defaults_diags = {
diff --git a/drivers/gpu/drm/amd/display/dc/link/link_detection.c b/drivers/gpu/drm/amd/display/dc/link/link_detection.c
index a131e30fd7d6..17904de4f155 100644
--- a/drivers/gpu/drm/amd/display/dc/link/link_detection.c
+++ b/drivers/gpu/drm/amd/display/dc/link/link_detection.c
@@ -593,6 +593,10 @@ static bool detect_dp(struct dc_link *link,
 			/* DP SST branch */
 			link->type = dc_connection_sst_branch;
 	} else {
+		if (link->dc->debug.disable_dp_plus_plus_wa &&
+				link->link_enc->features.flags.bits.IS_UHBR20_CAPABLE)
+			return false;
+
 		/* DP passive dongles */
 		sink_caps->signal = dp_passive_dongle_detection(link->ddc,
 								sink_caps,
-- 
2.34.1