UART_IER_UUE
if (!((offset == UART_IER) && (value & UART_IER_UUE)))
port->ier = UART_IER_RLSI|UART_IER_RDI|UART_IER_RTOIE|UART_IER_UUE;
serial8250_early_out(port, UART_IER, ier & UART_IER_UUE); /* no interrupt */
serial8250_early_out(port, UART_IER, ier & UART_IER_UUE);
serial_out(up, UART_IER, iersave & ~UART_IER_UUE);
if (!(serial_in(up, UART_IER) & UART_IER_UUE)) {
serial_out(up, UART_IER, iersave | UART_IER_UUE);
if (serial_in(up, UART_IER) & UART_IER_UUE) {
up->ier |= UART_IER_UUE;
serial_out(up, UART_IER, UART_IER_UUE);
up->ier = UART_IER_RLSI | UART_IER_RDI | UART_IER_RTOIE | UART_IER_UUE;
up->ier |= UART_IER_UUE;
serial_out(up, UART_IER, UART_IER_UUE);
serial_out(up, UART_IER, UART_IER_UUE);