return "unknown"; 
return NULL; 
static inline const char *siu_type_name(struct uart_port *port){	switch (port->type) {	case PORT_VR41XX_SIU:		return "SIU";	case PORT_VR41XX_DSIU:		return "DSIU";	}	return "unknown";}
4520	/local/tlutelli/issta_data/temp/c/2005_temp/2005/4520/eae936e21bd726f9d9555f2262d439fbcd61dccf/vr41xx_siu.c/buggy/drivers/serial/vr41xx_siu.c