[PATCH 13/17] drm/amd/display: add monitor patch to disable SCDC read/write

[Rodrigo Siqueira]

From: Martin Leung <martin.leung at amd.com>

[why]
customer issue: found that for their specific panel, EDID register space
being overwritten during SCDC read write

[how]
customer accepted HDMI 2 features not working - disabled SCDC read/write
as well as HDMI 2 in general based on monitor patch

Signed-off-by: Martin Leung <martin.leung at amd.com>
Reviewed-by: Chris Park <Chris.Park at amd.com>
Acked-by: Rodrigo Siqueira <Rodrigo.Siqueira at amd.com>
---
 drivers/gpu/drm/amd/display/dc/core/dc_link.c             | 4 ++++
 drivers/gpu/drm/amd/display/dc/core/dc_link_ddc.c         | 8 ++++++++
 drivers/gpu/drm/amd/display/dc/dc_types.h                 | 1 +
 drivers/gpu/drm/amd/display/dc/dcn10/dcn10_link_encoder.c | 5 +++++
 4 files changed, 18 insertions(+)

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 bed57051f04d..66d8d56f6abd 100644
--- a/drivers/gpu/drm/amd/display/dc/core/dc_link.c
+++ b/drivers/gpu/drm/amd/display/dc/core/dc_link.c
@@ -977,6 +977,10 @@ static bool dc_link_detect_helper(struct dc_link *link,
 		if ((prev_sink != NULL) && ((edid_status == EDID_THE_SAME) || (edid_status == EDID_OK)))
 			same_edid = is_same_edid(&prev_sink->dc_edid, &sink->dc_edid);
 
+		if (&sink->edid_caps.panel_patch.skip_scdc_overwrite)
+			link->ctx->dc->debug.hdmi20_disable = true;
+
+
 		if (link->connector_signal == SIGNAL_TYPE_DISPLAY_PORT &&
 			sink_caps.transaction_type == DDC_TRANSACTION_TYPE_I2C_OVER_AUX) {
 			/*
diff --git a/drivers/gpu/drm/amd/display/dc/core/dc_link_ddc.c b/drivers/gpu/drm/amd/display/dc/core/dc_link_ddc.c
index a49c10d5df26..a5586f68b4da 100644
--- a/drivers/gpu/drm/amd/display/dc/core/dc_link_ddc.c
+++ b/drivers/gpu/drm/amd/display/dc/core/dc_link_ddc.c
@@ -686,6 +686,10 @@ void dal_ddc_service_write_scdc_data(struct ddc_service *ddc_service,
 	uint8_t write_buffer[2] = {0};
 	/*Lower than 340 Scramble bit from SCDC caps*/
 
+	if (ddc_service->link->local_sink &&
+		ddc_service->link->local_sink->edid_caps.panel_patch.skip_scdc_overwrite)
+		return;
+
 	dal_ddc_service_query_ddc_data(ddc_service, slave_address, &offset,
 			sizeof(offset), &sink_version, sizeof(sink_version));
 	if (sink_version == 1) {
@@ -715,6 +719,10 @@ void dal_ddc_service_read_scdc_data(struct ddc_service *ddc_service)
 	uint8_t offset = HDMI_SCDC_TMDS_CONFIG;
 	uint8_t tmds_config = 0;
 
+	if (ddc_service->link->local_sink &&
+		ddc_service->link->local_sink->edid_caps.panel_patch.skip_scdc_overwrite)
+		return;
+
 	dal_ddc_service_query_ddc_data(ddc_service, slave_address, &offset,
 			sizeof(offset), &tmds_config, sizeof(tmds_config));
 	if (tmds_config & 0x1) {
diff --git a/drivers/gpu/drm/amd/display/dc/dc_types.h b/drivers/gpu/drm/amd/display/dc/dc_types.h
index 122c96455792..1490732a4b44 100644
--- a/drivers/gpu/drm/amd/display/dc/dc_types.h
+++ b/drivers/gpu/drm/amd/display/dc/dc_types.h
@@ -229,6 +229,7 @@ struct dc_panel_patch {
 	unsigned int extra_t12_ms;
 	unsigned int extra_delay_backlight_off;
 	unsigned int extra_t7_ms;
+	unsigned int skip_scdc_overwrite;
 };
 
 struct dc_edid_caps {
diff --git a/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_link_encoder.c b/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_link_encoder.c
index 1a37c90e9d43..d3617d6785a7 100644
--- a/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_link_encoder.c
+++ b/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_link_encoder.c
@@ -782,6 +782,11 @@ bool dcn10_link_encoder_validate_output_with_stream(
 	struct dcn10_link_encoder *enc10 = TO_DCN10_LINK_ENC(enc);
 	bool is_valid;
 
+	//if SCDC (340-600MHz) is disabled, set to HDMI 1.4 timing limit
+	if (stream->sink->edid_caps.panel_patch.skip_scdc_overwrite &&
+		enc10->base.features.max_hdmi_pixel_clock > 300000)
+		enc10->base.features.max_hdmi_pixel_clock = 300000;
+
 	switch (stream->signal) {
 	case SIGNAL_TYPE_DVI_SINGLE_LINK:
 	case SIGNAL_TYPE_DVI_DUAL_LINK:
-- 
2.25.0