drm/amd/display: Add DSC Support for Synaptics Cascaded MST Hub

[platform/kernel/linux-starfive.git] / drivers / gpu / drm / amd / display / amdgpu_dm / amdgpu_dm_mst_types.c

diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c
index e25e1b2..30de0aa 100644 (file)
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c
@@ -212,6 +212,21 @@ bool needs_dsc_aux_workaround(struct dc_link *link)
        return false;
 }
 
+bool is_synaptics_cascaded_panamera(struct dc_link *link, struct drm_dp_mst_port *port)
+{
+       u8 branch_vendor_data[4] = { 0 }; // Vendor data 0x50C ~ 0x50F
+
+       if (drm_dp_dpcd_read(port->mgr->aux, DP_BRANCH_VENDOR_SPECIFIC_START, &branch_vendor_data, 4) == 4) {
+               if (link->dpcd_caps.branch_dev_id == DP_BRANCH_DEVICE_ID_90CC24 &&
+                               IS_SYNAPTICS_CASCADED_PANAMERA(link->dpcd_caps.branch_dev_name, branch_vendor_data)) {
+                       DRM_INFO("Synaptics Cascaded MST hub\n");
+                       return true;
+               }
+       }
+
+       return false;
+}
+
 static bool validate_dsc_caps_on_connector(struct amdgpu_dm_connector *aconnector)
 {
        struct dc_sink *dc_sink = aconnector->dc_sink;
@@ -235,6 +250,10 @@ static bool validate_dsc_caps_on_connector(struct amdgpu_dm_connector *aconnecto
            needs_dsc_aux_workaround(aconnector->dc_link))
                aconnector->dsc_aux = &aconnector->mst_root->dm_dp_aux.aux;
 
+       /* synaptics cascaded MST hub case */
+       if (!aconnector->dsc_aux && is_synaptics_cascaded_panamera(aconnector->dc_link, port))
+               aconnector->dsc_aux = port->mgr->aux;
+
        if (!aconnector->dsc_aux)
                return false;