Fix lockup caused by serial driver not clearing
receive interrupt if flip buffer becomes full.
Signed-off-by: Paul Fulghum <[email protected]>
--- a/drivers/char/serial.c 2004-09-29 09:08:35.000000000 -0500
+++ b/drivers/char/serial.c 2004-09-29 09:09:07.000000000 -0500
@@ -573,8 +573,19 @@
do {
if (tty->flip.count >= TTY_FLIPBUF_SIZE) {
tty->flip.tqueue.routine((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(info, UART_RX);
+ icount->overrun++;
+ *status = serial_inp(info, UART_LSR);
+ } while ((*status & UART_LSR_DR) && (max_count-- > 0));
return; // if TTY_DONT_FLIP is set
+ }
}
ch = serial_inp(info, UART_RX);
*tty->flip.char_buf_ptr = ch;