From: Paul Fulghum Fix lockup caused by 8520 serial driver not clearing receive interrupt if flip buffer becomes full. Signed-off-by: Paul Fulghum Signed-off-by: Andrew Morton --- 25-akpm/drivers/serial/8250.c | 13 ++++++++++++- 1 files changed, 12 insertions(+), 1 deletion(-) diff -puN drivers/serial/8250.c~serial-8250-receive-lockup-fix drivers/serial/8250.c --- 25/drivers/serial/8250.c~serial-8250-receive-lockup-fix 2004-10-21 14:55:03.951201432 -0700 +++ 25-akpm/drivers/serial/8250.c 2004-10-21 14:55:03.956200672 -0700 @@ -982,8 +982,19 @@ receive_chars(struct uart_8250_port *up, do { if (unlikely(tty->flip.count >= TTY_FLIPBUF_SIZE)) { tty->flip.work.func((void *)tty); - if (tty->flip.count >= TTY_FLIPBUF_SIZE) + if (tty->flip.count >= TTY_FLIPBUF_SIZE) { + /* no room in flip buffer, discard rx FIFO contents to clear IRQ + * *FIXME* Hardware with auto flow control + * would benefit from leaving the data in the FIFO and + * disabling the rx IRQ until space becomes available. + */ + do { + serial_inp(up, UART_RX); + up->port.icount.overrun++; + *status = serial_inp(up, UART_LSR); + } while ((*status & UART_LSR_DR) && (max_count-- > 0)); return; /* if TTY_DONT_FLIP is set */ + } } ch = serial_inp(up, UART_RX); *tty->flip.char_buf_ptr = ch; _