device_getenv_string
device_getenv_string(dev, "flow_ctrl", flowctrl, sizeof(flowctrl),
device_getenv_string(dev, "flow_ctrl", flowctrl, sizeof(flowctrl),
device_getenv_string(dev, "flow_ctrl", flowctrl, sizeof(flowctrl),
device_getenv_string(dev, "flow_ctrl", flowctrl, sizeof(flowctrl),
void device_getenv_string(device_t dev, const char *knob,