tag	line	file	source code
UART_TX	242	drivers/char/console.c	serial_echo_outb(*s, UART_TX);
UART_TX	247	drivers/char/console.c	serial_echo_outb(13, UART_TX);
UART_TX	418	drivers/char/serial.c	serial_outp(info, UART_TX, info->x_char);
UART_TX	433	drivers/char/serial.c	serial_out(info, UART_TX, info->xmit_buf[info->xmit_tail++]);