rk3566不支持hdmi异显吗

void DrmHwcTwo::HandleDisplayHotplug(hwc2_display_t displayid, int state) {
  auto cb = callbacks_.find(HWC2::Callback::Hotplug);
  if (cb == callbacks_.end())
    return;

  if(isRK3566(resource_manager_.getSocId())){
      ALOGD_IF(LogLevel(DBG_DEBUG),"HandleDisplayHotplug skip display-id=%" PRIu64 " state=%d",displayid,state);
      if(displayid != HWC_DISPLAY_PRIMARY){
        auto &drmDevices = resource_manager_.getDrmDevices();
        for (auto &device : drmDevices) {
          if(state==DRM_MODE_CONNECTED)
            device->SetCommitMirrorDisplayId(displayid);
          else
            device->SetCommitMirrorDisplayId(-1);
        }
      }
      return;
  }

  if(displayid == HWC_DISPLAY_PRIMARY)
    return;

  auto hotplug = reinterpret_cast<HWC2_PFN_HOTPLUG>(cb->second.func);
  hotplug(cb->second.data, displayid,
          (state == DRM_MODE_CONNECTED ? HWC2_CONNECTION_CONNECTED
                                       : HWC2_CONNECTION_DISCONNECTED));
}

为什么针对rk3566做特殊处理，不通知上层进行hotplug？
如果rk3566支持hdmi异显的话，要如何配置？