[PATCH 04/27] drm/amd/display: read mso dpcd caps

[Wayne Lin]

From: Hansen Dsouza <Hansen.Dsouza at amd.com>

[Why & How]
Read if panel support multi-sst links

Reviewed-by: Charlene Liu <charlene.liu at amd.com>
Signed-off-by: Hansen Dsouza <Hansen.Dsouza at amd.com>
Signed-off-by: Wayne Lin <wayne.lin at amd.com>
---
 drivers/gpu/drm/amd/display/dc/dc_dp_types.h          |  2 ++
 .../display/dc/link/protocols/link_dp_capability.c    | 11 +++++++++++
 2 files changed, 13 insertions(+)

diff --git a/drivers/gpu/drm/amd/display/dc/dc_dp_types.h b/drivers/gpu/drm/amd/display/dc/dc_dp_types.h
index 8bb628ab7855..22c2173c687f 100644
--- a/drivers/gpu/drm/amd/display/dc/dc_dp_types.h
+++ b/drivers/gpu/drm/amd/display/dc/dc_dp_types.h
@@ -1220,6 +1220,8 @@ struct dpcd_caps {
 	struct replay_info pr_info;
 	uint16_t edp_oled_emission_rate;
 	union dp_receive_port0_cap receive_port0_cap;
+	/* Indicates the number of SST links supported by MSO (Multi-Stream Output) */
+	uint8_t mso_cap_sst_links_supported;
 };
 
 union dpcd_sink_ext_caps {
diff --git a/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_capability.c b/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_capability.c
index 0785c030f6a6..da19f6a3b42b 100644
--- a/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_capability.c
+++ b/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_capability.c
@@ -2100,6 +2100,17 @@ void detect_edp_sink_caps(struct dc_link *link)
 		core_link_read_dpcd(link, DP_SINK_EMISSION_RATE,
 				(uint8_t *)&link->dpcd_caps.edp_oled_emission_rate,
 				sizeof(link->dpcd_caps.edp_oled_emission_rate));
+
+	/*
+	 * Read Multi-SST (Single Stream Transport) capability
+	 * for eDP version 1.4 or higher.
+	 */
+	if (link->dpcd_caps.dpcd_rev.raw >= DP_EDP_14)
+		core_link_read_dpcd(
+			link,
+			DP_EDP_MSO_LINK_CAPABILITIES,
+			(uint8_t *)&link->dpcd_caps.mso_cap_sst_links_supported,
+			sizeof(link->dpcd_caps.mso_cap_sst_links_supported));
 }
 
 bool dp_get_max_link_enc_cap(const struct dc_link *link, struct dc_link_settings *max_link_enc_cap)
-- 
2.37.3